Hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) are believed to play a major role in viral clearance and disease pathogenesis during HBV infection. To clarify the differences in host immune respons...Hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) are believed to play a major role in viral clearance and disease pathogenesis during HBV infection. To clarify the differences in host immune responses between self-limited and chronic HBV infections, we constructed three HLA-A*0201/HBV tetramers with immunodominant epitopes of core18-27, polymerase 575-583 and envelope 335-343, and analyzed the HBV-specific CTLs in peripheral blood mononuclear cells (PBMCs) from patients infected with HBV. The frequencies and expansion ability of HBV-specific CD8+T cells in most self-limited HBV infected individuals were higher than those in chronic HBV-infected patients. HBV-specific CD8+T cells could be induced by in vitro peptide stimulation from chronic patients with a low level of serum HBV-DNA but not from those with a high level of serum HBV-DNA. In chronic infection, no significant correlation was found either between the frequencies of HBV-specific CD8^+ T cells and the viral load, or between the frequencies and the levels of alanine transaminase. Our results suggested that the frequencies of HBV-specific CTLs are not the main determinant of immune-mediated protection in chronic HBV infection and immunotherapeutic approaches should be aimed at not only boosting a HBV-specific CD8^+T response but also improving its function.展开更多
Objective: To investigate potential human leucocyte antigen(HLA)-A2-restricted epitope peptides of glypican-3(GPC3) and determine the cytotoxicity of peptidespecific cytotoxic T lymphocytes(CTLs) against hepatocellula...Objective: To investigate potential human leucocyte antigen(HLA)-A2-restricted epitope peptides of glypican-3(GPC3) and determine the cytotoxicity of peptidespecific cytotoxic T lymphocytes(CTLs) against hepatocellular carcinoma(HCC) cells.Methods: The potential HLA-A*0201-restricted GPC3 peptides were screened using computer algorithms, T2 cell-binding affinity and stability of peptide/HLA-A*0201 complex assay. The peptide-specific CTLs were generated and their cytotoxicity against GPC3+SMMC 7721 and Hep G2 cells was detected using IFN-g based enzymelinked immunospot and lactate dehydrogenase release assays in vitro.Results: A total of six peptides were identified for bindings to HAL-A2 and the GPC3522–530 and GPC3 229–237 peptides with HLA-A*0201 molecules displayed high binding affinity and stability. The CTLs induced by the GPC3 522–530 or positive control GPC3 144–152 peptide responded to the peptide by producing IFN-g, which were abrogated by treatment with anti-HLA-A2 antibody. The GPC3 522–530-specific CTLs responded to and killed SMMC 7721 and Hep G2 cells, instead of GPC3-silenced SMMC7721 or Hep G2 cells. GPC3 522–530-specific CTLs response to HCC cells was blocked by anti-HLA-A2 antibody.Conclusions: The GPC3 522–530 peptide contains antigen-determinant and its specific CTLs can effectively kill HCC in a HLA-A2-restricted and peptide-dependent manner. Our findings suggest that this peptide may be valuable for development of therapeutic vaccine.展开更多
Objective To evaluate the effect of the active specific immunotherapy with leukemia vaccine in the malignant hematopoietic diseases. Methods We established the animal models by inoculating C 57 BL/6 rats with FB...Objective To evaluate the effect of the active specific immunotherapy with leukemia vaccine in the malignant hematopoietic diseases. Methods We established the animal models by inoculating C 57 BL/6 rats with FBL 3 erythroleukemia cells and prepared three types of tumor vaccine, which were administered on the rats respectively. The MTT colorimetric assay was adopted 2 and 4 weeks later to test the cytotoxicity of macrophage( M Φ ) and that of cytotoxic T lymphocyte(CTL) derived from the rats injected with tumor vaccines, and compared the results with the control group. Results With the growth of erythroleulemia cells in the rats, the cellular immunity was seriously depressed, and the inhibition of specific cellular immunity was later than that of non specific cellular immunity. The tumor vaccine made from inactivated tumor cells, IFA and cytokines (rGM CSF, rIL 2 and rIL 6), promote the cellular immunity of tumor burden rats, especially the specific cellular immunity more efficiently than that of tumor vaccine made from inactivated tumor cells and IFA, but the third vaccine made from inactivated tumor cells alone has no effect. Conclusion The tumor vaccine made from inactivated tumor cells with addition of IFA and cytokines (rGM CSF, rIL 2 and rIL 6) provides a promising future in the active specific immunotherapy against hematopoietic tumor.展开更多
Objective: To established methods for cryopreserving peripheral blood mononuclear cells (PBMCs) andproducing DCs from cryopreserved PBMCs. Methods:Mature DCs were generated from cryopreserved PBMCs by using IL-4, GM...Objective: To established methods for cryopreserving peripheral blood mononuclear cells (PBMCs) andproducing DCs from cryopreserved PBMCs. Methods:Mature DCs were generated from cryopreserved PBMCs by using IL-4, GM-CSF, TNF-a, IL-1b, IL-6, pgE2 and LPS. The phenotype of the resultant DCs was investigated by flow cytometry. The functions of the resultant DCs were verified by Elispot assay. Results: The resultant DCs expressed high levels of HLA ABC, HLA DR, costimulatory molecules and the DC maturation marker CD83. The mature DCs wegenerated from frozen PBMCs were able to prime CD8 T cells into long term IFN-g producing peptide specific CTL. Conclusion: The DCs we developed from cryopreservedPBMC were fully mature and had the capability tostimulate immune reaction. Thus, we developed a method to generate functional mature DC from cryopreservedPBMC.展开更多
Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cy...Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes(CTLs)induced by dendritic cell line DC2.4 overexpressing Cdc25C,and the feasibility of Cdc25C as a component in hepatoma immunotherapy.Methods The mouse Cdc25C gene was ligated into a lentiviral vector,and transfected into DC2.4 cells.The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA,respectively.CD8^(+)T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech,Germany,and co-cultured with DC2.4 cells for one week as effector cells.Then,IL-2,granzyme B and perforin were detected in the CTL culture medium by ELISA.Next,time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells.Meanwhile,the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.Results The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection.DC2.4 cells transfected with LV-Cdc25C secreted more IL-6,IL-12,TNF-αand IFN-γ,and had higher expression levels of CD40,CD86,CCR7 and MHC-II than unaltered DC2.4 cells.The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2,granzyme B and perforin to elicit Cdc25C-specific CTLs,and induced the higher cytotoxicity in Hepa1-6 cell lines(P<0.05),but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.Conclusion DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs,and result in a strong cellular immune response.The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.展开更多
Human immunodeficiency virus(HIV)has had an insightful impact about the state of healthiness of human immune system.Due to great improvement in drug therapy,HIV infections have been reduced by 17%over the past eight y...Human immunodeficiency virus(HIV)has had an insightful impact about the state of healthiness of human immune system.Due to great improvement in drug therapy,HIV infections have been reduced by 17%over the past eight years.It has been proved that most effective treatment HAART(Highly Active Anti Retroviral Therapy)mainly controls the diseases progression but it does not eradicate the diseases completely.Reverse Transcriptase Inhibitor drugs specially associated with virus specific Cytotoxic T-Lymphocyte(CTL)that declines with disease progression. CTL responses against AIDS pathogenesis could be potential in the dynamics of virus replication, recognition and clearance of infected cells.In this research article a mathematical model has been proposed on the basis of CTL response suppression in the chronic phase of infection due to presence of virus.We also consider the growth of the virus population from the infected CD4^+T cells budding process and from the other infected cells like macrophages and thymocytes.Our analytical and numerical studies are consistent with existing observations from allied areas.展开更多
Background The response of patients with chronic hepatitis B (CHB) to antiviral therapy against hepatitis B virus (HBV) is related to the base line level of HBV DNA, but the mechanism is not clear. The present stu...Background The response of patients with chronic hepatitis B (CHB) to antiviral therapy against hepatitis B virus (HBV) is related to the base line level of HBV DNA, but the mechanism is not clear. The present study aimed to understand the possible relationship between the level of HBV DNA and HBV-specific, nonspecific cytotoxic T lymphocytes (CTL) and natural killer (NK) cells of CHB patients and the mechanism how the HBV DNA level influences the antiviral therapeutic effect. Methods Totally 100 adult patients with CHB who were positive for HBV DNA, HBeAg and (HLA)-A2 were enrolled into this study. HBV DNA was tested by real time fluorescence quantitative polymerase chain reaction (PCR). HBV specific and nonspecific CTL and NK cells were tested by flowcytometry. Serum alanine aminotransferase (ALT) and total bilirubin (TBil) were determined for each patient using routine biochemical tests. The 100 cases were assigned to two groups based on their HBV DNA level: group A had 48 cases, their HBV DNA level was 104-105 copies/ml, group B had 52 cases their HBV DNA level was 106-107 copies/ml. HBV specific CTL, nonspecific CTL, NK cells, ALT and TBil of the two groups were compared. Results HBV DNA level of groups A and B was (4.81±0.39) log10 copies/ml and (6.81±0.40) log10 copies/ml, respectively (t=25.32, P 〈0.001). HBV specific CTL and NK cells of group A were significantly higher than those of group B (P 〈0.001 for both). Nonspecific CTL of group A was significantly lower than that of group B (P 〈0.01). ALT and TBil of group A were significantly lower than those of group B (P 〈0.01 and P 〈0.05, respectively). Conclusions Serum HBV DNA level of patients with CHB is related to HBV specific CTL, nonspecific CTL and NK cells, which might result in inflammatory reaction of liver and cause more damage to liver function. Mechanism of HBV DNA level affecting the efficacy of anti-viral treatment may be related to the levels of HBV specific CTL and NK cells.展开更多
Background Epstein-Barr virus (EBV) is a herpesvirus commonly associated with several malignant diseases including nasopharyngeal carcinoma (NPC), which is a common cancer in Southeastern Asia. Previous studies sh...Background Epstein-Barr virus (EBV) is a herpesvirus commonly associated with several malignant diseases including nasopharyngeal carcinoma (NPC), which is a common cancer in Southeastern Asia. Previous studies showed that plasma levels of EBV-DNA might be a sensitive and reliable biomarker for the diagnosis, staging and evaluating of therapy for NPC. There are a few analyses of the levels of EBV-latent membrane protein 2 (LMP2)-specific cytotoxic T-lymphocytes (CTLs) in patients with NPC. This study was conducted to investigate the levels of EBV-LMP2-specific CTLs, EBV-DNA load and the level of CD4^+CD25^+T cells in such patients. Methods From February 2006 to April 2006, 62 patients with NPC, 40 healthy virus carriers positive for EBV viral capsid antigen (EBV-IgA-VCA) and 40 controls were enrolled in the study. We used a highly sensitive ELISPOT assay, real-time polymerase chain reaction (PCR) and flow cytometry to measure the EBV-LMP2-specific CTL response, the EBV DNA load and the level of CD4^+CD25^+T cells, respectively. Results The EBV-LMP2-specific CTL responses of the samples from the control, healthy virus carriers and patients with NPC were significantly different from the LMP2 epitopes, with the control and healthy virus carrier samples displaying a stronger response in three cases. There were significant differences in EBV DNA load in serum between NPC and the healthy groups; patients with NPC at stages Ⅲ or Ⅳ had significantly higher viral loads compared with those at stages Ⅰ or Ⅱ. A significantly higher percentage of CD4^+CD25^+ T lymphocytes were detected in the patients, compared with healthy virus carriers and healthy controls. Moreover, patients with advanced stages of NPC (Ⅲ and Ⅳ) had significantly higher percentages than the patients with early stages (Ⅰ and Ⅱ). Conclusions Patients with NPC are frequently unable to establish or maintain sufficient immunosurveillance to control proliferating B cells harboring EBV and to destroy the tumor cells that express immunodominant LMP2 proteins. Controlling the activity of CD4^+CD25^+T cells and elevating CD8^+ cells specific for LMP2 epitopes could be an effective immunotherapy for patients with NPC.展开更多
Background Oxymatrine has certain antiviral effects in the treatment of chronic hepatitis B (CHB), but its exact mechanism is unclear. The objective of the present study was to explore oxymatrine's antiviral mechan...Background Oxymatrine has certain antiviral effects in the treatment of chronic hepatitis B (CHB), but its exact mechanism is unclear. The objective of the present study was to explore oxymatrine's antiviral mechanism by studying its effect on the hepatitis B virus (HBV) specific cytotoxic T lymphocyte (CTL) surface programmed death receptor-1 (PD-1) expression in CHB patients. Methods Sixty-five CHB patients who had HBV DNA≥104 copies/mL positive HBeAg, positive human leukocyte antigen (HLA)-A2, alanine aminotransferase (ALT) 〉2xupper limit of normal value (ULN) were randomly divided into two groups: treatment group (n=33), treated with an intravenous infusion of 600 mg oxymatrine in glucose solution once a day for a month, then with a 200 mg oxymatrine oral capsule three times a day, and a 200 mg silibin meglumine tablet three times a day; control group (n=32) patients were treated only with silibin meglumine tablet, method and dosage were the same as those of treatment group. Three months later, peripheral blood HBV-specific CTL surface PD-1 expression, HBV-specific CTL level, HBV DNA, HBeAg, and results of liver function tests were analyzed and compared. Results Three months post-treatment, in the treatment group, peripheral blood HBV-specific CTL surface PD-1 expression ((19.42±15.94)%) decreased significantly compared to the pretreatment level ((31.30±24.06)%; P 〈0.05), and decreased significantly compared to that of control group three months after treatment ((29.45±21.62)%; P 〈0.05). HBV-specific CTL level ((0.42±0.07)%) significantly increased compared with the pretreatment ((0.29±0.15)%; P 〈0.01), and the control group posttreatment level was (0.31±0.15)% (P 〈0.05). HBV DNA level in 11 cases became negative (HBV DNA〈500 copies/ml, 33.33%), which was higher than that of the control group after treatment (two cases, 6.25%; X2=7.45, P 〈0.01), HBeAg of nine cases turned negative (27.27%), which was higher than that of the control group after treatment (one case, 3.13%; X2=7.27, P 〈0.01). Conclusion Oxymatrine could downregulate peripheral blood HBV-specific CTL surface PD-1 expression in CHB patients, increase HBV-specific CTL level, which may be one of the possible mechanisms by which oxymatrine clears or inhibits HBV in CHB Datients.展开更多
The Fas/FasL system transmits intracellular apoptotic signaling, inducing cell apoptosis. However, Fas signaling also exerts non-apoptotic functions in addition to inducing tumor cell apoptosis. For example, Fas signa...The Fas/FasL system transmits intracellular apoptotic signaling, inducing cell apoptosis. However, Fas signaling also exerts non-apoptotic functions in addition to inducing tumor cell apoptosis. For example, Fas signaling induces lung cancer tumor cells to produce prostaglandin E2 (PGE2) and recruit myeloid-derived suppressor cells (MDSCs). Activated cytotoxic T lymphocytes (CTLs) induce and express high levels of FasL, but the effects of Fas activation initiated by FasL in CTLs on apoptosis-resistant tumor cells remain largely unclear. We purified activated CD8^+ T cells from OT-1 mice, evaluated the regulatory effects of Fas activation on tumor cell escape and investigated the relevant mechanisms. We found that CTLs induced tumor cells to secrete PGE2 and increase tumor cell-mediated chemoattraction of MDSCs via Fas signaling, which was favorable to tumor growth. Our results indicate that CTLs may participate in the tumor immune evasion process. To the best of our knowledge, this is a novel mechanism by which CTLs play a role in tumor escape. Our findings implicate a strategy to enhance the antitumor immune response via reduction of negative immune responses to tumors promoted by CTLs through Fas signaling.展开更多
Background Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte (CTL) numbers,immunophenotype,tumor-specificity,and in vivo residence time,migration,and distribu...Background Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte (CTL) numbers,immunophenotype,tumor-specificity,and in vivo residence time,migration,and distribution.Therefore,tracing in vivo persistence,migration,and distribution of CTLs is important for cancer immunotherapy.Methods Optimal staining concentration for CTL proliferation was determined by cell counting kit-8 (CCK-8) assay and killing efficiencies of CTLs or carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled melanoma antigen-specific cytotoxic T lymphocytes (CFSE-CTLs) for malignant melanoma cells in vitro were compared.Additionally,CFSE-CTLs were intravenously transfused to mice receiving B16 melanoma,and their residence time,migration,and distribution in vivo were observed by measuring fluorescence intensities of CFSE-CTLs per gram of tissue (%FI/g) in various tissues and analyzing tumor/non-tumor (T/NT) values.Anti-tumor effects of transferred CTLs and correlation between %FI/g and D-value of tumor size were analyzed.Results Five-micromolar CFSE was optimal for labeling CTLs with minimal cytotoxicity.No significant difference occurred between CTLs and CFSE-CTLs for tumor cell killing (P=0.849) or interleukin-2 (P=0.318) and interferon-y (P=0.201)levels.Distribution of CTLs in vivo varied with time.A negative correlation between %FI/g in tumors and D-value of tumor sizes by Spearman correlation analysis was observed.CTLs were recruited to and killed tumors from 6 hours to 3 days after cell infusion.CTLs were observed up to three weeks later in the tumor,liver,kidneys,and spleen; this was related to the abundant blood supply or the nature of immune organs.Conclusions CCK-8 assay is a novel method to select optimal CFSE staining concentrations.Fluorescence intensity of transferred CTLs reflects their killing efficiency of tumors.CFSE fluorescent markers can trace in vivo CTL persistence,migration,and distribution because of its stability,long half-life,and low toxicity.展开更多
Background Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV pr...Background Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte (CTL) responses. However, complementary determining regions-based individual vaccines have disadvantages for wide clinical application. Although a recent study demonstrated that immunogenic peptides are derived from framework regions (FR) shared among patients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia (B-ALL). Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity.Methods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A^*0201-restricted CTL epitopes for each IgHV family. An antigen-specific T cell expansion system was used to generate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay. Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences available showed ≥98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature. Twelve nonapeptides of high HLA-A^*0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten (83%) of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 (3-11) shared among the IgHV1 family could be successfully generated from peripheral blood mononuclear cells of two HLA-A^*0201+ healthy donors in vitro and were capable of killing HLA-matched B-ALL cell clones belonging to the IgHV1 family. Conclusion Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specific cytotoxicity.展开更多
Background Cancer testis antigens (CTAs) are a novel group of tumor associated antigens.Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism,thus enhance t...Background Cancer testis antigens (CTAs) are a novel group of tumor associated antigens.Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism,thus enhance the immunogenicity of leukemia cells.However,few researches have ever focused on the questions that whether this immunostimulatory effect of decitabine could induce autologous CTA specific cytotoxic T lymphocytes (CTLs) in vivo,and if so,whether this effect contributes to disease control.In this study,we aimed to show that decitabine could induce specific autologous CTLs against some mouse CTAs in leukemia cells in vitro and in vivo.Methods Several mouse CTAs were screened by RT-PCR.CTL specific to one of the CTAs named P1A was detected and sorted by P1A specific dimer by flow cytometry.The activity of specific CTLs was measured by real time RT-PCR.Results We firstly screened expression of some CTAs in mouse leukemia cells before and after decitabine treatment and found that decitabine treatment did up-regulate expression of many CTAs.Then we measured the CTLs' activity specific to a mouse CTA P1A in vivo and showed that this activity increased after decitabine treatment.Finally,we sorted these in vivo induced P1A specific CTLs by flow cytometry and demonstrated their cytotoxicity against decitabine treated leukemia cells.Conclusions Our study showed the autologous immune response induced by decitabine in vivo.And more importantly,we firstly proved that this response may contribute to disease control.We believe that this immunostimulatory effect is another anti-cancer mechanism of decitabine,and this special effect would inspire new applications of decitabine in the field of leukemia treatment in the future.展开更多
In this paper,we study a mathematical model of Hepatitis C Virus(HCV)infection.We present a compartmental mathematical model involving healthy hepatocytes,infected hepatocytes,non-activated dendritic cells,activated d...In this paper,we study a mathematical model of Hepatitis C Virus(HCV)infection.We present a compartmental mathematical model involving healthy hepatocytes,infected hepatocytes,non-activated dendritic cells,activated dendritic cells and cytotoxic T lymphocytes.The derivative used is of non-local fractional order and with non-singular kernel.The existence and uniqueness of the system is proven and its stability is analyzed.Then,by applying the Laplace Adomian decomposition method for the fractional derivative,we present the semi-analytical solution of the model.Finally,some numerical simulations are performed for concrete values of the parameters and several graphs are plotted to reveal the qualitative properties of the solutions.展开更多
Objective To explore the effect of Telbivudine(LDT)Tablet combined with Jianpi Bushen Recipe(JBR)on serum hepatitis B virus(HBV)specific cytotoxic T lymphocyte(CTL)and HBe Ag seroconversion in chronic hepatitis B(CHB)...Objective To explore the effect of Telbivudine(LDT)Tablet combined with Jianpi Bushen Recipe(JBR)on serum hepatitis B virus(HBV)specific cytotoxic T lymphocyte(CTL)and HBe Ag seroconversion in chronic hepatitis B(CHB)patients.Methods Totally90 HBe Ag-positive and human leukocyte antigen(HLA)-A2 positive CHB patients were randomly assigned to展开更多
Exosomes (EXO) derived from dendritic cells (DC) and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison o...Exosomes (EXO) derived from dendritic cells (DC) and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin (OVA) and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCOVA-derived EXO (EXODC) can more efficiently stimulate naive OVA-specific CD8^+ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO (EXOEG7). In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity. Cellular & Molecular Immunology. 2006;3(3):205-211.展开更多
Epstein-Barr virus (EBV) associated nasopharyngeal carcinoma (NPC) is a high incidence tumor in Southeast Asia. Among EBV encoded proteins, latent membrane protein 2A (LMP2A) is an important antigen for T cell t...Epstein-Barr virus (EBV) associated nasopharyngeal carcinoma (NPC) is a high incidence tumor in Southeast Asia. Among EBV encoded proteins, latent membrane protein 2A (LMP2A) is an important antigen for T cell therapy of EBV. In this study, we predicted six HLA-A2 restricted CTL candidate epitopes of LMP2A by SYFPEITHI, NetMHC and MHCPred methods combined with the polynomial method. Subsequently, biological functions of these peptides were tested by experiments in vitro. In ELISPOT assay, the positive response of the LMP2A specific CTL stimulated by three (LMP2A264.272, LMP2A426-434 and LMP2A3s6.364) of six peptides respectively showed that the numbers of spots forming cells (SFC) ranged from 55.7 to 80.6 SFC/5 x 104 CO8^+ T cells and the responding index (RI) ranged from 5.4 to 7. These three epitope-specific CTLs could effectively kill specific HLA-A2- expressing target cells. As a result, LMP2A264.272 (QLSPLLGAV), LMP2A426.434 (CLGGLLTMV) and LMP2A356.364 (FLYALALLL) were identified as LMP2A-specific CD8^+ T-cell epitopes. It would be useful to clarify immune response toward EBV and to develop a vaccine against EBV-correlative NPC.展开更多
We previously identified human phosphatidylethanolamine-binding protein 4(hPEBP4)as an antiapoptotic protein with increased expression levels in breast,ovarian and prostate cancer cells,but low expression levels in no...We previously identified human phosphatidylethanolamine-binding protein 4(hPEBP4)as an antiapoptotic protein with increased expression levels in breast,ovarian and prostate cancer cells,but low expression levels in normal tissues,which makes hPEBP4 an attractive target for immunotherapy.Here,we developed hPEBP4-derived immunogenic peptides for inducing antigen-specific cytotoxic T lymphocytes(CTLs)targeting breast cancer.A panel of hPEBP4-derived peptides predicted by peptide-MHC-binding algorithms was evaluated to characterize their HLAA2.1 affinity and immunogenicity.We identified a novel immunogenic peptide,P40–48(TLFCQGLEV),that was capable of eliciting specific CTL responses in HLA-A2.1/K^(b) transgenic mice,as well as in peripheral blood lymphocytes from breast cancer patients.Furthermore,amino-acid substitutions in the P40–48 sequence improved its immunogenicity against hPEBP4,a self-antigen,thus circumventing tolerance.We designed peptide analogs by preferred auxiliary HLA-A^(*)0201 anchor residue replacement,which induced CTLs that were crossreactive to the native peptide.Several analogs were able to stably bind to HLA-A^(*)0201 and elicit specific CTL responses better than the native sequence.Importantly,adoptive transfer of CTLs induced by vaccination with two analogs more effectively inhibited tumor growth than the native peptide.These data indicate that peptide analogs with high immunogenicity represent promising candidates for peptide-mediated therapeutic cancer vaccines.展开更多
Adoptive transfer of cytomegalovirus(CMV)-specific cytotoxic T lymphocytes(CMV-CTLs)from original transplant donors or third-party donors was effective for the treatment of CMV infection after allogenic stem cell tran...Adoptive transfer of cytomegalovirus(CMV)-specific cytotoxic T lymphocytes(CMV-CTLs)from original transplant donors or third-party donors was effective for the treatment of CMV infection after allogenic stem cell transplantation(allo-SCT),but the antiviral activity of CMV-CTL types has not been compared.To determine whether third-party CMV-CTLs provide comparable long-term antiviral efficacy to transplant donor CMV-CTLs,we first compared the antiviral abilities of transplant donors and third-party CMV-CTLs for treatment of CMV infection in two mouse models,compared the in vivo recovery of CMV-specific immunity,and analyzed the underlying mechanisms driving sustained antiviral immunity.The results showed that both donor and third-party CMV-CTLs effectively combated systemic CMV infection by reducing CMV pathology and tumor burden 28 days postinfusion.The in vivo recovery of CMV-specific immunity after CMV-CTL infusion was comparable in both groups.A detailed analysis of the source of recovered CMV-CTLs showed the proliferation and expansion of graft-derived endogenous CMV-CTLs in both groups.Our clinical study,which enrolled 31 patients who received third-party CMV-CTLs and 62 matched pairs of individuals who received transplant donor CMV-CTLs for refractory CMV infection,further showed that adoptive therapy with donor or third-party CMV-CTLs had comparable clinical responses without significant therapy-related toxicity.We observed strong expansion of CD8+tetramer+T cells and proliferation of recipient endogenous CMV-CTLs after CMV-CTL infusion,which were associated with a reduced or cleared viral load.Our data confirmed that adoptive therapy with third-party or transplant donor CMV-CTLs triggered comparable antiviral responses to CMV infection that might be mediated by restoration of endogenous CMV-specific immunity.展开更多
基金supported by grants from the National Key Basic Research Program of China (No.20014CB510008,No.2005CB522901)the National Natural Sciences Foundation of China (No.30400412)
文摘Hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) are believed to play a major role in viral clearance and disease pathogenesis during HBV infection. To clarify the differences in host immune responses between self-limited and chronic HBV infections, we constructed three HLA-A*0201/HBV tetramers with immunodominant epitopes of core18-27, polymerase 575-583 and envelope 335-343, and analyzed the HBV-specific CTLs in peripheral blood mononuclear cells (PBMCs) from patients infected with HBV. The frequencies and expansion ability of HBV-specific CD8+T cells in most self-limited HBV infected individuals were higher than those in chronic HBV-infected patients. HBV-specific CD8+T cells could be induced by in vitro peptide stimulation from chronic patients with a low level of serum HBV-DNA but not from those with a high level of serum HBV-DNA. In chronic infection, no significant correlation was found either between the frequencies of HBV-specific CD8^+ T cells and the viral load, or between the frequencies and the levels of alanine transaminase. Our results suggested that the frequencies of HBV-specific CTLs are not the main determinant of immune-mediated protection in chronic HBV infection and immunotherapeutic approaches should be aimed at not only boosting a HBV-specific CD8^+T response but also improving its function.
基金supported by a grant from the Medical Research Projects of Hainan Health Department(grant number 2013-009)Science and Technology Funding Project of Guangzhou,China(Grant No.201604020009)
文摘Objective: To investigate potential human leucocyte antigen(HLA)-A2-restricted epitope peptides of glypican-3(GPC3) and determine the cytotoxicity of peptidespecific cytotoxic T lymphocytes(CTLs) against hepatocellular carcinoma(HCC) cells.Methods: The potential HLA-A*0201-restricted GPC3 peptides were screened using computer algorithms, T2 cell-binding affinity and stability of peptide/HLA-A*0201 complex assay. The peptide-specific CTLs were generated and their cytotoxicity against GPC3+SMMC 7721 and Hep G2 cells was detected using IFN-g based enzymelinked immunospot and lactate dehydrogenase release assays in vitro.Results: A total of six peptides were identified for bindings to HAL-A2 and the GPC3522–530 and GPC3 229–237 peptides with HLA-A*0201 molecules displayed high binding affinity and stability. The CTLs induced by the GPC3 522–530 or positive control GPC3 144–152 peptide responded to the peptide by producing IFN-g, which were abrogated by treatment with anti-HLA-A2 antibody. The GPC3 522–530-specific CTLs responded to and killed SMMC 7721 and Hep G2 cells, instead of GPC3-silenced SMMC7721 or Hep G2 cells. GPC3 522–530-specific CTLs response to HCC cells was blocked by anti-HLA-A2 antibody.Conclusions: The GPC3 522–530 peptide contains antigen-determinant and its specific CTLs can effectively kill HCC in a HLA-A2-restricted and peptide-dependent manner. Our findings suggest that this peptide may be valuable for development of therapeutic vaccine.
文摘Objective To evaluate the effect of the active specific immunotherapy with leukemia vaccine in the malignant hematopoietic diseases. Methods We established the animal models by inoculating C 57 BL/6 rats with FBL 3 erythroleukemia cells and prepared three types of tumor vaccine, which were administered on the rats respectively. The MTT colorimetric assay was adopted 2 and 4 weeks later to test the cytotoxicity of macrophage( M Φ ) and that of cytotoxic T lymphocyte(CTL) derived from the rats injected with tumor vaccines, and compared the results with the control group. Results With the growth of erythroleulemia cells in the rats, the cellular immunity was seriously depressed, and the inhibition of specific cellular immunity was later than that of non specific cellular immunity. The tumor vaccine made from inactivated tumor cells, IFA and cytokines (rGM CSF, rIL 2 and rIL 6), promote the cellular immunity of tumor burden rats, especially the specific cellular immunity more efficiently than that of tumor vaccine made from inactivated tumor cells and IFA, but the third vaccine made from inactivated tumor cells alone has no effect. Conclusion The tumor vaccine made from inactivated tumor cells with addition of IFA and cytokines (rGM CSF, rIL 2 and rIL 6) provides a promising future in the active specific immunotherapy against hematopoietic tumor.
文摘Objective: To established methods for cryopreserving peripheral blood mononuclear cells (PBMCs) andproducing DCs from cryopreserved PBMCs. Methods:Mature DCs were generated from cryopreserved PBMCs by using IL-4, GM-CSF, TNF-a, IL-1b, IL-6, pgE2 and LPS. The phenotype of the resultant DCs was investigated by flow cytometry. The functions of the resultant DCs were verified by Elispot assay. Results: The resultant DCs expressed high levels of HLA ABC, HLA DR, costimulatory molecules and the DC maturation marker CD83. The mature DCs wegenerated from frozen PBMCs were able to prime CD8 T cells into long term IFN-g producing peptide specific CTL. Conclusion: The DCs we developed from cryopreservedPBMC were fully mature and had the capability tostimulate immune reaction. Thus, we developed a method to generate functional mature DC from cryopreservedPBMC.
基金the National Natural Science Foundation of China(No.81160264)the Natural Science Foundation of Guangxi Province(No.2016GXNSFAA380267 and No.2018GXNSFAA281071)+1 种基金the Guangxi First-class Discipline Project for Basic Medicine Sciences(No.GXFCDP-BMS-2018)the Research Enhancement Project for Junior Faculty in Higher Education Institutes of Guangxi(No.2018KY0419).
文摘Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes(CTLs)induced by dendritic cell line DC2.4 overexpressing Cdc25C,and the feasibility of Cdc25C as a component in hepatoma immunotherapy.Methods The mouse Cdc25C gene was ligated into a lentiviral vector,and transfected into DC2.4 cells.The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA,respectively.CD8^(+)T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech,Germany,and co-cultured with DC2.4 cells for one week as effector cells.Then,IL-2,granzyme B and perforin were detected in the CTL culture medium by ELISA.Next,time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells.Meanwhile,the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.Results The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection.DC2.4 cells transfected with LV-Cdc25C secreted more IL-6,IL-12,TNF-αand IFN-γ,and had higher expression levels of CD40,CD86,CCR7 and MHC-II than unaltered DC2.4 cells.The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2,granzyme B and perforin to elicit Cdc25C-specific CTLs,and induced the higher cytotoxicity in Hepa1-6 cell lines(P<0.05),but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.Conclusion DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs,and result in a strong cellular immune response.The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.
基金Research is supported by the Government of India,Ministry of Science and Technology,Mathematical Science office,No.SR/S4/MS:558/08
文摘Human immunodeficiency virus(HIV)has had an insightful impact about the state of healthiness of human immune system.Due to great improvement in drug therapy,HIV infections have been reduced by 17%over the past eight years.It has been proved that most effective treatment HAART(Highly Active Anti Retroviral Therapy)mainly controls the diseases progression but it does not eradicate the diseases completely.Reverse Transcriptase Inhibitor drugs specially associated with virus specific Cytotoxic T-Lymphocyte(CTL)that declines with disease progression. CTL responses against AIDS pathogenesis could be potential in the dynamics of virus replication, recognition and clearance of infected cells.In this research article a mathematical model has been proposed on the basis of CTL response suppression in the chronic phase of infection due to presence of virus.We also consider the growth of the virus population from the infected CD4^+T cells budding process and from the other infected cells like macrophages and thymocytes.Our analytical and numerical studies are consistent with existing observations from allied areas.
文摘Background The response of patients with chronic hepatitis B (CHB) to antiviral therapy against hepatitis B virus (HBV) is related to the base line level of HBV DNA, but the mechanism is not clear. The present study aimed to understand the possible relationship between the level of HBV DNA and HBV-specific, nonspecific cytotoxic T lymphocytes (CTL) and natural killer (NK) cells of CHB patients and the mechanism how the HBV DNA level influences the antiviral therapeutic effect. Methods Totally 100 adult patients with CHB who were positive for HBV DNA, HBeAg and (HLA)-A2 were enrolled into this study. HBV DNA was tested by real time fluorescence quantitative polymerase chain reaction (PCR). HBV specific and nonspecific CTL and NK cells were tested by flowcytometry. Serum alanine aminotransferase (ALT) and total bilirubin (TBil) were determined for each patient using routine biochemical tests. The 100 cases were assigned to two groups based on their HBV DNA level: group A had 48 cases, their HBV DNA level was 104-105 copies/ml, group B had 52 cases their HBV DNA level was 106-107 copies/ml. HBV specific CTL, nonspecific CTL, NK cells, ALT and TBil of the two groups were compared. Results HBV DNA level of groups A and B was (4.81±0.39) log10 copies/ml and (6.81±0.40) log10 copies/ml, respectively (t=25.32, P 〈0.001). HBV specific CTL and NK cells of group A were significantly higher than those of group B (P 〈0.001 for both). Nonspecific CTL of group A was significantly lower than that of group B (P 〈0.01). ALT and TBil of group A were significantly lower than those of group B (P 〈0.01 and P 〈0.05, respectively). Conclusions Serum HBV DNA level of patients with CHB is related to HBV specific CTL, nonspecific CTL and NK cells, which might result in inflammatory reaction of liver and cause more damage to liver function. Mechanism of HBV DNA level affecting the efficacy of anti-viral treatment may be related to the levels of HBV specific CTL and NK cells.
基金The study was supported by grants from the Guangxi Science Foundation (No. 0640114) and the "863" program of China (No. 2006AA02A229).
文摘Background Epstein-Barr virus (EBV) is a herpesvirus commonly associated with several malignant diseases including nasopharyngeal carcinoma (NPC), which is a common cancer in Southeastern Asia. Previous studies showed that plasma levels of EBV-DNA might be a sensitive and reliable biomarker for the diagnosis, staging and evaluating of therapy for NPC. There are a few analyses of the levels of EBV-latent membrane protein 2 (LMP2)-specific cytotoxic T-lymphocytes (CTLs) in patients with NPC. This study was conducted to investigate the levels of EBV-LMP2-specific CTLs, EBV-DNA load and the level of CD4^+CD25^+T cells in such patients. Methods From February 2006 to April 2006, 62 patients with NPC, 40 healthy virus carriers positive for EBV viral capsid antigen (EBV-IgA-VCA) and 40 controls were enrolled in the study. We used a highly sensitive ELISPOT assay, real-time polymerase chain reaction (PCR) and flow cytometry to measure the EBV-LMP2-specific CTL response, the EBV DNA load and the level of CD4^+CD25^+T cells, respectively. Results The EBV-LMP2-specific CTL responses of the samples from the control, healthy virus carriers and patients with NPC were significantly different from the LMP2 epitopes, with the control and healthy virus carrier samples displaying a stronger response in three cases. There were significant differences in EBV DNA load in serum between NPC and the healthy groups; patients with NPC at stages Ⅲ or Ⅳ had significantly higher viral loads compared with those at stages Ⅰ or Ⅱ. A significantly higher percentage of CD4^+CD25^+ T lymphocytes were detected in the patients, compared with healthy virus carriers and healthy controls. Moreover, patients with advanced stages of NPC (Ⅲ and Ⅳ) had significantly higher percentages than the patients with early stages (Ⅰ and Ⅱ). Conclusions Patients with NPC are frequently unable to establish or maintain sufficient immunosurveillance to control proliferating B cells harboring EBV and to destroy the tumor cells that express immunodominant LMP2 proteins. Controlling the activity of CD4^+CD25^+T cells and elevating CD8^+ cells specific for LMP2 epitopes could be an effective immunotherapy for patients with NPC.
文摘Background Oxymatrine has certain antiviral effects in the treatment of chronic hepatitis B (CHB), but its exact mechanism is unclear. The objective of the present study was to explore oxymatrine's antiviral mechanism by studying its effect on the hepatitis B virus (HBV) specific cytotoxic T lymphocyte (CTL) surface programmed death receptor-1 (PD-1) expression in CHB patients. Methods Sixty-five CHB patients who had HBV DNA≥104 copies/mL positive HBeAg, positive human leukocyte antigen (HLA)-A2, alanine aminotransferase (ALT) 〉2xupper limit of normal value (ULN) were randomly divided into two groups: treatment group (n=33), treated with an intravenous infusion of 600 mg oxymatrine in glucose solution once a day for a month, then with a 200 mg oxymatrine oral capsule three times a day, and a 200 mg silibin meglumine tablet three times a day; control group (n=32) patients were treated only with silibin meglumine tablet, method and dosage were the same as those of treatment group. Three months later, peripheral blood HBV-specific CTL surface PD-1 expression, HBV-specific CTL level, HBV DNA, HBeAg, and results of liver function tests were analyzed and compared. Results Three months post-treatment, in the treatment group, peripheral blood HBV-specific CTL surface PD-1 expression ((19.42±15.94)%) decreased significantly compared to the pretreatment level ((31.30±24.06)%; P 〈0.05), and decreased significantly compared to that of control group three months after treatment ((29.45±21.62)%; P 〈0.05). HBV-specific CTL level ((0.42±0.07)%) significantly increased compared with the pretreatment ((0.29±0.15)%; P 〈0.01), and the control group posttreatment level was (0.31±0.15)% (P 〈0.05). HBV DNA level in 11 cases became negative (HBV DNA〈500 copies/ml, 33.33%), which was higher than that of the control group after treatment (two cases, 6.25%; X2=7.45, P 〈0.01), HBeAg of nine cases turned negative (27.27%), which was higher than that of the control group after treatment (one case, 3.13%; X2=7.27, P 〈0.01). Conclusion Oxymatrine could downregulate peripheral blood HBV-specific CTL surface PD-1 expression in CHB patients, increase HBV-specific CTL level, which may be one of the possible mechanisms by which oxymatrine clears or inhibits HBV in CHB Datients.
基金The work was supported by the Specialized Research Fund for the Chinese National 973 Project (2013CB530502), the Doctoral Program of Higher Education of China (20110101110105), the Project of the Chinese National Nature Science Foundation (31370902, 31070795, 31270944), the Projects in Science and Technology Plan of Zhejiang Province (013C33G2010434) of China, the National Key Science and Technology Specific Proiect of China (2012ZX10002006), the National High Technology Research and Development Program (2012AA020900), and the Project of the Chinese National Natural Science Fund Committee for Talent Cultivation (J1103603).
文摘The Fas/FasL system transmits intracellular apoptotic signaling, inducing cell apoptosis. However, Fas signaling also exerts non-apoptotic functions in addition to inducing tumor cell apoptosis. For example, Fas signaling induces lung cancer tumor cells to produce prostaglandin E2 (PGE2) and recruit myeloid-derived suppressor cells (MDSCs). Activated cytotoxic T lymphocytes (CTLs) induce and express high levels of FasL, but the effects of Fas activation initiated by FasL in CTLs on apoptosis-resistant tumor cells remain largely unclear. We purified activated CD8^+ T cells from OT-1 mice, evaluated the regulatory effects of Fas activation on tumor cell escape and investigated the relevant mechanisms. We found that CTLs induced tumor cells to secrete PGE2 and increase tumor cell-mediated chemoattraction of MDSCs via Fas signaling, which was favorable to tumor growth. Our results indicate that CTLs may participate in the tumor immune evasion process. To the best of our knowledge, this is a novel mechanism by which CTLs play a role in tumor escape. Our findings implicate a strategy to enhance the antitumor immune response via reduction of negative immune responses to tumors promoted by CTLs through Fas signaling.
文摘Background Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte (CTL) numbers,immunophenotype,tumor-specificity,and in vivo residence time,migration,and distribution.Therefore,tracing in vivo persistence,migration,and distribution of CTLs is important for cancer immunotherapy.Methods Optimal staining concentration for CTL proliferation was determined by cell counting kit-8 (CCK-8) assay and killing efficiencies of CTLs or carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled melanoma antigen-specific cytotoxic T lymphocytes (CFSE-CTLs) for malignant melanoma cells in vitro were compared.Additionally,CFSE-CTLs were intravenously transfused to mice receiving B16 melanoma,and their residence time,migration,and distribution in vivo were observed by measuring fluorescence intensities of CFSE-CTLs per gram of tissue (%FI/g) in various tissues and analyzing tumor/non-tumor (T/NT) values.Anti-tumor effects of transferred CTLs and correlation between %FI/g and D-value of tumor size were analyzed.Results Five-micromolar CFSE was optimal for labeling CTLs with minimal cytotoxicity.No significant difference occurred between CTLs and CFSE-CTLs for tumor cell killing (P=0.849) or interleukin-2 (P=0.318) and interferon-y (P=0.201)levels.Distribution of CTLs in vivo varied with time.A negative correlation between %FI/g in tumors and D-value of tumor sizes by Spearman correlation analysis was observed.CTLs were recruited to and killed tumors from 6 hours to 3 days after cell infusion.CTLs were observed up to three weeks later in the tumor,liver,kidneys,and spleen; this was related to the abundant blood supply or the nature of immune organs.Conclusions CCK-8 assay is a novel method to select optimal CFSE staining concentrations.Fluorescence intensity of transferred CTLs reflects their killing efficiency of tumors.CFSE fluorescent markers can trace in vivo CTL persistence,migration,and distribution because of its stability,long half-life,and low toxicity.
文摘Background Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte (CTL) responses. However, complementary determining regions-based individual vaccines have disadvantages for wide clinical application. Although a recent study demonstrated that immunogenic peptides are derived from framework regions (FR) shared among patients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia (B-ALL). Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity.Methods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A^*0201-restricted CTL epitopes for each IgHV family. An antigen-specific T cell expansion system was used to generate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay. Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences available showed ≥98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature. Twelve nonapeptides of high HLA-A^*0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten (83%) of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 (3-11) shared among the IgHV1 family could be successfully generated from peripheral blood mononuclear cells of two HLA-A^*0201+ healthy donors in vitro and were capable of killing HLA-matched B-ALL cell clones belonging to the IgHV1 family. Conclusion Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specific cytotoxicity.
基金This work was supported by the grants from the National Basic Research Program of China (No. 2005CB522400), National Natural Science Foundation of China (Nos. 90919044, 30971297, 81000221 and 81170518), Capital Medical Development Scientific Research Fund (No. 2007-2040), National Public Health Grand Research Foundation (No. 201202017) and The Capital of the Public Health Project (No. Z 111107067311070). Conflict of interest: none.
文摘Background Cancer testis antigens (CTAs) are a novel group of tumor associated antigens.Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism,thus enhance the immunogenicity of leukemia cells.However,few researches have ever focused on the questions that whether this immunostimulatory effect of decitabine could induce autologous CTA specific cytotoxic T lymphocytes (CTLs) in vivo,and if so,whether this effect contributes to disease control.In this study,we aimed to show that decitabine could induce specific autologous CTLs against some mouse CTAs in leukemia cells in vitro and in vivo.Methods Several mouse CTAs were screened by RT-PCR.CTL specific to one of the CTAs named P1A was detected and sorted by P1A specific dimer by flow cytometry.The activity of specific CTLs was measured by real time RT-PCR.Results We firstly screened expression of some CTAs in mouse leukemia cells before and after decitabine treatment and found that decitabine treatment did up-regulate expression of many CTAs.Then we measured the CTLs' activity specific to a mouse CTA P1A in vivo and showed that this activity increased after decitabine treatment.Finally,we sorted these in vivo induced P1A specific CTLs by flow cytometry and demonstrated their cytotoxicity against decitabine treated leukemia cells.Conclusions Our study showed the autologous immune response induced by decitabine in vivo.And more importantly,we firstly proved that this response may contribute to disease control.We believe that this immunostimulatory effect is another anti-cancer mechanism of decitabine,and this special effect would inspire new applications of decitabine in the field of leukemia treatment in the future.
基金supported by the Agencia Estatal de Investigacin(AEI)of Spain,co-financed by the European Fund for Regional Development(FEDER)corresponding to the 2014-2020 multiyear financial framework,project PID2020-113275GB-I00Instituto de Salud Carlos II,grant COV20/00617Xunta de Galicia under grant ED431C 2019/02.
文摘In this paper,we study a mathematical model of Hepatitis C Virus(HCV)infection.We present a compartmental mathematical model involving healthy hepatocytes,infected hepatocytes,non-activated dendritic cells,activated dendritic cells and cytotoxic T lymphocytes.The derivative used is of non-local fractional order and with non-singular kernel.The existence and uniqueness of the system is proven and its stability is analyzed.Then,by applying the Laplace Adomian decomposition method for the fractional derivative,we present the semi-analytical solution of the model.Finally,some numerical simulations are performed for concrete values of the parameters and several graphs are plotted to reveal the qualitative properties of the solutions.
文摘Objective To explore the effect of Telbivudine(LDT)Tablet combined with Jianpi Bushen Recipe(JBR)on serum hepatitis B virus(HBV)specific cytotoxic T lymphocyte(CTL)and HBe Ag seroconversion in chronic hepatitis B(CHB)patients.Methods Totally90 HBe Ag-positive and human leukocyte antigen(HLA)-A2 positive CHB patients were randomly assigned to
文摘Exosomes (EXO) derived from dendritic cells (DC) and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin (OVA) and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCOVA-derived EXO (EXODC) can more efficiently stimulate naive OVA-specific CD8^+ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO (EXOEG7). In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity. Cellular & Molecular Immunology. 2006;3(3):205-211.
基金supported by the National Nature Science Foundation of China (No.30571715)
文摘Epstein-Barr virus (EBV) associated nasopharyngeal carcinoma (NPC) is a high incidence tumor in Southeast Asia. Among EBV encoded proteins, latent membrane protein 2A (LMP2A) is an important antigen for T cell therapy of EBV. In this study, we predicted six HLA-A2 restricted CTL candidate epitopes of LMP2A by SYFPEITHI, NetMHC and MHCPred methods combined with the polynomial method. Subsequently, biological functions of these peptides were tested by experiments in vitro. In ELISPOT assay, the positive response of the LMP2A specific CTL stimulated by three (LMP2A264.272, LMP2A426-434 and LMP2A3s6.364) of six peptides respectively showed that the numbers of spots forming cells (SFC) ranged from 55.7 to 80.6 SFC/5 x 104 CO8^+ T cells and the responding index (RI) ranged from 5.4 to 7. These three epitope-specific CTLs could effectively kill specific HLA-A2- expressing target cells. As a result, LMP2A264.272 (QLSPLLGAV), LMP2A426.434 (CLGGLLTMV) and LMP2A356.364 (FLYALALLL) were identified as LMP2A-specific CD8^+ T-cell epitopes. It would be useful to clarify immune response toward EBV and to develop a vaccine against EBV-correlative NPC.
基金supported by grants from the National Key Basic Research Program of China(2013CB530502)(to NL)the National Natural Science Foundation of China(81672798 to NL,81672736 to YL,31670875 to SL,81671644 to YW,81788104 to XC)the Shanghai Committee of Science and Technology(09QH1402800,09SG35)(to NL).
文摘We previously identified human phosphatidylethanolamine-binding protein 4(hPEBP4)as an antiapoptotic protein with increased expression levels in breast,ovarian and prostate cancer cells,but low expression levels in normal tissues,which makes hPEBP4 an attractive target for immunotherapy.Here,we developed hPEBP4-derived immunogenic peptides for inducing antigen-specific cytotoxic T lymphocytes(CTLs)targeting breast cancer.A panel of hPEBP4-derived peptides predicted by peptide-MHC-binding algorithms was evaluated to characterize their HLAA2.1 affinity and immunogenicity.We identified a novel immunogenic peptide,P40–48(TLFCQGLEV),that was capable of eliciting specific CTL responses in HLA-A2.1/K^(b) transgenic mice,as well as in peripheral blood lymphocytes from breast cancer patients.Furthermore,amino-acid substitutions in the P40–48 sequence improved its immunogenicity against hPEBP4,a self-antigen,thus circumventing tolerance.We designed peptide analogs by preferred auxiliary HLA-A^(*)0201 anchor residue replacement,which induced CTLs that were crossreactive to the native peptide.Several analogs were able to stably bind to HLA-A^(*)0201 and elicit specific CTL responses better than the native sequence.Importantly,adoptive transfer of CTLs induced by vaccination with two analogs more effectively inhibited tumor growth than the native peptide.These data indicate that peptide analogs with high immunogenicity represent promising candidates for peptide-mediated therapeutic cancer vaccines.
基金DB is supported by grants from the German Research Foundation(361210922/RTG 2408 and SFB 854/A23).
文摘Adoptive transfer of cytomegalovirus(CMV)-specific cytotoxic T lymphocytes(CMV-CTLs)from original transplant donors or third-party donors was effective for the treatment of CMV infection after allogenic stem cell transplantation(allo-SCT),but the antiviral activity of CMV-CTL types has not been compared.To determine whether third-party CMV-CTLs provide comparable long-term antiviral efficacy to transplant donor CMV-CTLs,we first compared the antiviral abilities of transplant donors and third-party CMV-CTLs for treatment of CMV infection in two mouse models,compared the in vivo recovery of CMV-specific immunity,and analyzed the underlying mechanisms driving sustained antiviral immunity.The results showed that both donor and third-party CMV-CTLs effectively combated systemic CMV infection by reducing CMV pathology and tumor burden 28 days postinfusion.The in vivo recovery of CMV-specific immunity after CMV-CTL infusion was comparable in both groups.A detailed analysis of the source of recovered CMV-CTLs showed the proliferation and expansion of graft-derived endogenous CMV-CTLs in both groups.Our clinical study,which enrolled 31 patients who received third-party CMV-CTLs and 62 matched pairs of individuals who received transplant donor CMV-CTLs for refractory CMV infection,further showed that adoptive therapy with donor or third-party CMV-CTLs had comparable clinical responses without significant therapy-related toxicity.We observed strong expansion of CD8+tetramer+T cells and proliferation of recipient endogenous CMV-CTLs after CMV-CTL infusion,which were associated with a reduced or cleared viral load.Our data confirmed that adoptive therapy with third-party or transplant donor CMV-CTLs triggered comparable antiviral responses to CMV infection that might be mediated by restoration of endogenous CMV-specific immunity.