Identification of prognostic molecular subtypes and model based on CD8+ T cells for lung adenocarcinoma

Background:Cytotoxic T lymphocytes(CD8+T)cells function critically in mediating anti-tumor immune response in cancer patients.Characterizing the specific functions of CD8+T cells in lung adenocarcinoma(LUAD)could help better understand local anti-tumor immune responses and estimate the effect of immunotherapy.Methods:Gens related to CD8+T cells were identified by cluster analysis based on the single-cell sequencing data of three LUAD tissues and their paired normal tissues.Weighted gene co-expression network analysis(WGCNA),consensus clustering,differential expression analysis,least absolute shrinkage and selection operator(LASSO)and Cox regression analysis were conducted to classify molecular subtypes for LUAD and to develop a risk model using prognostic genes related to CD8+T cells.Expression of the genes in the prognostic model,their effects on tumor cell invasion,and interactions with CD8+T cells were verified by cell experiments.Results:This study defined two LUAD clusters(CD8+0 and CD8+1)based on CD8+T cells,with cluster CD8+0 being significantly associated with the prognosis of LUAD.Three heterogeneous subtypes(clusters 1,2,and 3)differing in prognosis,genome mutation events,and immune status were categorized using 42 prognostic genes.A prognostic model created based on 11 significant genes(including CD200R1,CLEC17A,ZC3H12D,GNG7,SNX30,CDCP1,NEIL3,IGF2BP1,RHOV,ABCC2,and KRT81)was able to independently estimate the death risk for patients in different LUAD cohorts.Moreover,the model also showed general applicability in external validation cohorts.Low-risk patients could benefit more from taking immunotherapy and were significantly related to the resistance to anticancer drugs.The results from cell experiments demonstrated that the expression of CD200R1,CLEC17A,ZC3H12D,GNG7,and SNX30 was significantly downregulated,while that of CDCP1,NEIL3,IGF2BP1,RHOV,ABCC2 and KRT81 was upregulated in LUAD cells.Inhibition of CD200R1 greatly increased the invasiveness of the LUAD cells,but inhibiting CDCP1 expression weakened the invasion ability of LUAD cells.Conclusion:This study defined two prognostic CD8+T cell clusters and classified three heterogeneous molecular subtypes for LUAD.A prognostic model predictive of the potential effects of immunotherapy on LUAD patients was developed.

Predicting the Prognosis and Immunotherapeutic Response of Triple-Negative Breast Cancer by Constructing a Prognostic Model Based on CD8+T Cell-Related Immune Genes

Objective Triple-negative breast cancer(TNBC)poses a significant challenge for treatment efficacy.CD8+T cells,which are pivotal immune cells,can be effectively analyzed for differential gene expression across diverse cell populations owing to rapid advancements in sequencing technology.By leveraging these genes,our objective was to develop a prognostic model that accurately predicts the prognosis of patients with TNBC and their responsiveness to immunotherapy.Methods Sample information and clinical data of TNBC were sourced from The Cancer Genome Atlas and METABRIC databases.In the initial stage,we identified 67 differentially expressed genes associated with immune response in CD8+T cells.Subsequently,we narrowed our focus to three key genes,namely CXCL13,GBP2,and GZMB,which were used to construct a prognostic model.The accuracy of the model was assessed using the validation set data and receiver operating characteristic(ROC)curves.Furthermore,we employed various methods,including Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway,immune infiltration,and correlation analyses with CD274(PD-L1)to explore the model's predictive efficacy in immunotherapeutic responses.Additionally,we investigated the potential underlying biological pathways that contribute to divergent treatment responses.Results We successfully developed a model capable of predicting the prognosis of patients with TNBC.The areas under the curve(AUC)values for the 1-,3-,and 5-year survival predictions were 0.618,0.652,and 0.826,respectively.Employing this risk model,we stratified the samples into high-and low-risk groups.Through KEGG enrichment analysis,we observed that the high-risk group predominantly exhibited enrichment in metabolism-related pathways such as drug and chlorophyll metabolism,whereas the low-risk group demonstrated significant enrichment in cytokine pathways.Furthermore,immune landscape analysis revealed noteworthy variations between(PD-L1)expression and risk scores,indicating that our model effectively predicted the response of patients to immune-based treatments.Conclusion Our study demonstrates the potential of CXCL13,GBP2,and GZMB as prognostic indicators of clinical outcomes and immunotherapy responses in patients with TNBC.These findings provide valuable insights and novel avenues for developing immunotherapeutic approaches targeting TNBC.

Revolutionizing tumor immunotherapy:unleashing the power of progenitor exhausted T cells

In exploring persistent infections and malignancies, a distinctive subgroup of CD8^(+) T cells, progenitor exhausted CD8^(+) T(Tpex) cells, has been identified. These Tpex cells are notable for their remarkable self-renewal and rapid proliferation abilities. Recent strides in immunotherapy have demonstrated that Tpex cells expand and differentiate into responsive exhausted CD8^(+) T cells, thus underscoring their critical role in the immunotherapeutic retort. Clinical examinations have further clarified a robust positive correlation between the proportional abundance of Tpex cells and enhanced clinical prognosis. Tpex cells have found noteworthy applications in the formulation of inventive immunotherapeutic approaches against tumors. This review describes the functions of Tpex cells in the tumor milieu, particularly their potential utility in tumor immunotherapy. Precisely directing Tpex cells may be essential to achieving successful outcomes in immunotherapy against tumors.

The Mechanisms of CD8+ T Cells Exhaustion in the Tumor Microenvironment and Immune Therapy

In the tumor immune microenvironment, CD8+ T cells differentiate towards functional failure. The exhaustion of CD8+ T cells (Tex) showed varying degrees of effect dysfunction, loss of proliferation ability, and sustained high expression of a variety of inhibitory receptors, with metabolic and epigenetic changes. Tex cells are heterogeneous, including several subsets with different characteristics at different stages of differentiation. Immune checkpoint inhibitors (ICIs) can restore the effect or function of Tex cells, indicating that this T cell subset plays a key role in tumor immunotherapy. The understanding of the mechanism of CD8+ T cell exhaustion will be helpful to the implementation of tumor immunotherapy. This article reviews the production, differentiation and functional characteristics of Tex cells and their relationship with tumor immunotherapy.

Peripheral CD4^(+)CD8^(+) double positive T cells:A potential marker to evaluate renal impairment susceptibility during systemic lupus erythematosus

Lupus nephritis(LN) has a high incidence in systemic lupus erythematosus(SLE) patients, but there is a lack of sensitive predictive markers. The purpose of the study was to investigate the association between the CD4^(+)CD8^(+)double positive T(DPT) lymphocytes and LN. The study included patients with SLE without renal impairment(SLE-NRI), LN, nephritic syndrome(NS), or nephritis. Peripheral blood lymphocyte subsets were analyzed by flow cytometry. Biochemical measurements were performed with peripheral blood in accordance with the recommendations proposed by the National Center for Clinical Laboratories. The proportions of DPT cells in the LN group were significantly higher than that in the SLE-NRI group(t=4.012, P<0.001), NS group(t=3.240,P=0.001), and nephritis group(t=2.57, P=0.011). In the LN group, the risk of renal impairment increased significantly in a DPT cells proportion-dependent manner. The risk of LN was 5.136 times(95% confidence interval, 2.115–12.473) higher in cases with a high proportion of DPT cells than those whose proportion of DPT cells within the normal range. These findings indicated that the proportion of DPT cells could be a potential marker to evaluate LN susceptibility, and the interference of NS and nephritis could be effectively excluded when assessing the risk of renal impairment during SLE with DPT cell proportion.

Natural course of chronic hepatitis B is characterized by changing patterns of programmed death type-1 of CD8-positive T cells

AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study.PD-1 expression in total T cells was detected by flow cytometry.Levels of total CD8+T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/ PD-L1 blockage. RESULTS:The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection,did not significantly increase in the immune tolerance phase,and returned to normal in the inactive virus carrier stage.Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection.However,it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection.Furthermore,the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection. CONCLUSION:The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection.

Combined TIM-3 and PD-1 blockade restrains hepatocellular carcinoma development by facilitating CD4+ and CD8+T cellmediated antitumor immune responses

BACKGROUND Immune checkpoint inhibitors(ICIs)targeting programmed cell death protein 1(PD-1)and T cell immunoglobulin and mucin domain-containing protein 3(TIM-3)are beneficial to the resumption of anti-tumor immunity response and hold extreme potential as efficient therapies for certain malignancies.However,ICIs with a single target exhibit poor overall response rate in hepatocellular carcinoma(HCC)patients due to the complex pathological mechanisms of HCC.AIM To investigate the effects of combined TIM-3 and PD-1 blockade on tumor development in an HCC mouse model,aiming to identify more effective immunotherapies and provide more treatment options for HCC patients.METHODS The levels of PD-1 and TIM-3 on CD4+and CD8+T cells from tumor tissues,ascites,and matched adjacent tissues from HCC patients were determined with flow cytometry.An HCC xenograft mouse model was established and treated with anti-TIM-3 monoclonal antibody(mAb)and/or anti-PD-1 mAb.Tumor growth in each group was measured.Hematoxylin and eosin staining and immunohistochemical staining were used to evaluate T cell infiltration in tumors.The percentage of CD4+and CD8+T cells in tissue samples from mice was tested with flow cytometry.The percentages of PD-1+CD8+,TIM-3+CD8+,and PD-1+TIM-3+CD8+T cells was accessed by flow cytometry.The levels of the cytokines including tumor necrosis factor alpha(TNF-α),interferon-γ(IFN-γ),interleukin(IL)-6,and IL-10 in tumor tissues were gauged with enzyme-linked immunosorbent assay kits.RESULTS We confirmed that PD-1 and TIM-3 expression was substantially upregulated in CD4+and CD8+T cells isolated from tumor tissues and ascites of HCC patients.TIM-3 mAb and PD-1 mAb treatment both reduced tumor volume and weight,while combined blockade had more substantial anti-tumor effects than individual treatment.Then we showed that combined therapy increased T cell infiltration into tumor tissues,and downregulated PD-1 and TIM-3 expression on CD8+T cells in tumor tissues.Moreover,combined treatment facilitated the production of T cell effector cytokines TNF-α and IFN-γ,and reduced the production of immunosuppressive cytokines IL-10 and IL-6 in tumor tissues.Thus,we implicated that combined blockade could ameliorate T cell exhaustion in HCC mouse model.CONCLUSION Combined TIM-3 and PD-1 blockade restrains HCC development by facilitating CD4+ and CD8+T cell-mediated antitumor immune responses.

Glutamine deprivation impairs function of infiltrating CD8^(+)T cells in hepatocellular carcinoma by inducing mitochondrial damage and apoptosis

BACKGROUND The functions of infiltrating CD8^(+)T cells are often impaired due to tumor cells causing nutrient deprivation in the tumor microenvironment.Thus,the mechanisms of CD8^(+)T cell dysfunction have become a hot research topic,and there is increased interest on how changes in metabolomics correlate with CD8^(+)T cell dysfunction.AIM To investigate whether and how glutamine metabolism affects the function of infiltrating CD8^(+)T cells in hepatocellular carcinoma.METHODS Immunohistochemical staining and immunofluorescence were performed on surgically resected liver tissues from patients.Differentially expressed genes in infiltrating CD8^(+)T cells in hepatocellular carcinoma were detected using RNA sequencing.Activated CD8^(+)T cells were co-cultured with Huh-7 cells for 3 d.The function and mitochondrial status of CD8^(+)T cells were analyzed by flow cytometry,quantitative real-time polymerase chain reaction,and transmission electron microscopy.Next,CD8^(+)T cells were treated with the mitochondrial protective and damaging agents.Functional alterations in CD8^(+)T cells were detected by flow cytometry.Then,complete medium without glutamine was used to culture cells and their functional changes and mitochondrial status were detected.RESULTS There were a large number of infiltrating PD-1+CD8^(+)T cells in liver cancer tissues.Next,we cocultured CD8^(+)T cells and Huh-7 cells to explore the regulatory effect of hepatoma cells on CD8^(+)T cells.Flow cytometry results revealed increased PD-1 expression and decreased secretion of perforin(PRF1)and granzyme B(GZMB)by CD8^(+)T cells in the co-culture group.Meanwhile,JC-1 staining was decreased and the levels of reactive oxygen species and apoptosis were increased in CD8^(+)T cells of the co-culture group;additionally,the mitochondria of these cells were swollen.When CD8^(+)T cells were treated with the mitochondrial protective and damaging agents,their function was restored and inhibited,respectively,through the mitochondrial damage and apoptotic pathways.Subsequently,complete medium without glutamine was used to culture cells.As expected,CD8^(+)T cells showed functional downregulation,mitochondrial damage,and apoptosis.CONCLUSION Glutamine deprivation impairs the function of infiltrating CD8^(+)T cells in hepatocellular carcinoma through the mitochondrial damage and apoptotic pathways.

Neutrophils inhibit CD8^(+)T cells immune response by arginase-1 signaling in patients with sepsis

BACKGROUND:Patients with sepsis often exhibit an acute inflammatory response,followed by an immunosuppressive phase with a poor immune response.However,the underlying mechanisms have not been fully elucidated.METHODS:We sought to comprehensively characterize the transcriptional changes in neutrophils of patients with sepsis by transcriptome sequencing.Additionally,we conducted a series of experiments,including real-time quantitative polymerase chain reaction(RT-qPCR)and flow cytometry to investigate the role of arginase-1 signaling in sepsis.RESULTS:Through the analysis of gene expression profiles,we identified that the negative regulation of T cell activation signaling was enriched,and the expression of arginase-1 was high in neutrophils from patients with sepsis.Furthermore,we conducted flow cytometry and found that the function of CD8^(+)T cells in septic patients was impaired.Moreover,neutrophils from septic patients inhibited the percentage of polyfunctional effector CD8^(+)T cells through arginase-1.Additionally,the proportions of granzyme B^(+)IFN^(-)γ^(+)CD8^(+)T and TNF^(-)α^(+)IFN^(-)γ^(+)CD8^(+)T cells increased after inhibition of arginase-1 signaling.CONCLUSION:The impaired effector function of CD8^(+)T cells could be restored by blocking arginase-1 signaling in patients with sepsis.

The role of intestinal flora on tumorigenesis,progression,and the efficacy of PD-1/PD-L1 antibodies in colorectal cancer

Intestinal flora affects the maturation of the host immune system,serves as a biomarker and efficacy predictor in the immunotherapy of several cancers,and has an important role in the development of colorectal cancer(CRC).Anti-PD-1/PD-L1 antibodies have shown satisfactory results in MSI-H/d MMR CRC but performed poorly in patients with MSS/p MMR CRC.In recent years an increasing number of studies have shown that intestinal flora has an important impact on anti-PD-1/PD-L1 antibody efficacy in CRC patients.Preclinical and clinical evidence have suggested that anti-PD-1/PD-L1 antibody efficacy can be improved by altering the composition of the intestinal flora in CRC.Herein,we summarize the studies related to the influence of intestinal flora on anti-PD-1/PD-L1 antibody efficacy in CRC and discuss the potential underlying mechanism(s).We have focused on the impact of the intestinal flora on the efficacy and safety of anti-PD-1/PD-L1 antibodies in CRC and how to better utilize the intestinal flora as an adjuvant to improve the efficacy of anti-PD-1/PD-L1 antibodies.In addition,we have provided a basis for the potential of the intestinal flora as a new treatment modality and indicator for determining patient prognosis.

Human immune suppression is inducible by trichosanthin via CD8 cell-mediated pathway

Thichosanthin(Tk), a polypeptide with 249 amino acid residues isolated and purified from a Chinese medicinal herb, showed the capability of inducing abortion and was able to inhibit tumor growth and HIV replication. Owing to sequence homology of the peptide with a ribosomeinactivating protein, the downward activity of Tk was suggested to be related to its cytotoxic property. We report here, however, that Tk could exert potent inhibitory effects on human lymphoproliferative responses in vitro to allogeneic, mitogenic and soluble antigens with 50% inhibition doses ranged between 0.05 and 0.5 μg/ml. The lowresponsiveness caused by Tk was not due to toxic cytolysis. Rather, evidences suggested that, in the dose range adopted, the Tk-induced inhibition was attributable, at least in part, to immune suppression, in view of (1) Tk was more effective in the early stage of alloreactivity; (2)Suppression also occurred if responder cells were pulsetreated with Tk rather than cocultured; (3) Irradiated Tk-pulsed cells were capable of inducing suppression in a Tk-free culture; (4) Suppression could also be transferred by the supernatants of Tk-pulsed cultured cells; (5) Tkinduced immune suppression was diminished by depletion of CD8+ cells from the culture, and, finally; (6) Adding CD8+ cells back to the culture could restore the suppres Trichosanthin-induced humall immune suppression sion. Thus the possibility that Tk might function as a down-regulator by immunological mechanisms in human immune responses is discussed.

Specific CD8^+ T cell response immunotherapy for hepatocellular carcinoma and viral hepatitis

Hepatocellular carcinoma (HCC), chronic hepatitis B (CHB) and chronic hepatitis C (CHC) are characterized by exhaustion of the specific CD8+ T cell response. This process involves enhancement of negative co-stimulatory molecules, such as programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte antigen-4 (CTLA-4), 2B4, Tim-3, CD160 and LAG-3, which is linked to intrahepatic overexpression of some of the cognate ligands, such as PD-L1, on antigen presenting cells and thereby favouring a tolerogenic environment. Therapies that disrupt these negative signalling mechanisms represent promising therapeutic tools with the potential to restore reactivity of the specific CD8+ T cell response. In this review we discuss the impressive in vitro and in vivo results that have been recently achieved in HCC, CHB and CHC by blocking these negative receptors with monoclonal antibodies against these immune checkpoint modulators. The article mainly focuses on the role of CTLA-4 and PD-1 blocking monoclonal antibodies, the first ones to have reached clinical practice. The humanized monoclonal antibodies against CTLA-4 (tremelimumab and ipilimumab) and PD-1 (nivolumab and pembrolizumab) have yielded good results in testing of HCC and chronic viral hepatitis patients. Trelimumab, in particular, has shown a significant increase in the time to progression in HCC, while nivolumab has shown a remarkable effect on hepatitis C viral load reduction. The research on the role of ipilimumab, nivolumab and pembrolizumab on HCC is currently underway.

Expression of PD1 and BTLA on the CD8^+T Cell and γδT Cell Subsets in Peripheral Blood of Non-Small Cell Lung Cancer Patients

Objective To investigate the expression and regulation of programmed cell death protein 1(PD1),B lymphocyte and T lymphocyte attenuator(BTLA)in peripheral blood of patients with non-small cell lung cancer(NSCLC);to examine the correlation of the mRNA levels between PD and BTLA in NSCLC.Methods Flow cytometry was used to detect the expression of PD1 and BTLA on the surfaces of CD8^+T cells andγδ+T cells in the peripheral blood samples collected from 32 in-patients with stage IV NSCLC and 30 healthy individuals.We compared the expression of PD1 and BTLA on the surfaces ofγδ+T cells in the NSCLC patients with bone metastasis before and after the treatment of zoledronic acid.The correlations of PD1 and BTLA,as well as their ligands were analyzed using Pearson correlation analysis with the cBioPortal data platform.Results The frequency of PD1 on the surfaces of CD8^+T cells was significantly higher than that of theγδT cells in both healthy controls(t=2.324,P=0.024)and NSCLC patients(t=2.498,P=0.015).The frequency of PD1 on CD8^+T cells,rather than onγδ+T cells,was significantly upregulated in advanced NSCLC patients compared with that in healthy controls(t=4.829,P<0.001).The PD1+BTLA+γδT cells of the healthy controls were significantly lower than that of the NSCLC patients(t=2.422,P=0.0185).No differences in percentage of PD1+γδ+and BTLA+γδ+T cells were observed in 7 NSCLC patients with bone metastasis before and after zoledronic acid treatment.PD1 was positively correlated with BTLA in both lung adenocarcinoma(r=0.54;P<0.05)and lung squamous cell carcinoma(r=0.78;P<0.05).Conclusions The upregulation of co-inhibitory molecules occurs on the surfaces of both CD8^+T cells andγδT cells in advanced NSCLC,suggesting that these molecules were involved in regulating the inactivation of CD8^+T cells andγδ+T cells,immune escape and tumor invasion.

Neutrophils as key regulators of tumor immunity that restrict immune checkpoint blockade in liver cancer

Objective:Liver cancer is a deadly malignancy associated with high mortality and morbidity.Less than 20%of patients with advanced liver cancer respond to a single anti-PD-1 treatment.The high heterogeneity of neutrophils in the tumor immune microenvironment in liver cancer may contribute to resistance to immune checkpoint blockade(ICB).However,the underlying mechanism remains largely unknown.Methods:We established an orthotopic liver cancer model by using transposable elements to integrate the oncogenes Myc and KrasG12Dinto the genome in liver cells from conditional Trp53 null/null mice(pTMK/Trp53^(-/-)).Flow cytometry and immunohistochemistry were used to assess the changes in immune cells in the tumor microenvironment.An ex vivo coculture assay was performed to test the inhibitory effects of tumor-associated neutrophils(TANs)on CD8^(+)T cells.The roles of neutrophils,T cells,and NK cells were validated through antibody-mediated depletion.The efficacy of the combination of neutrophil depletion and ICB was evaluated.Results:Orthotropic pTMK/Trp53^(-/-)mouse liver tumors displayed a moderate response to anti-Ly6G treatment but not PD-1 blockade.Depletion of neutrophils increased the infiltration of CD8^(+)T cells and decreased the number of exhausted T cells in the tumor microenvironment.Furthermore,depletion of either CD8^(+)T or NK cells abrogated the antitumor efficacy of anti-Ly6G treatment.Moreover,the combination of anti-Ly6G with anti-PD-L1 enhanced the infiltration of cytotoxic CD8^(+)T cells and thereafter resulted in a significantly greater decrease in tumor burden.Conclusions:Our data suggest that TANs may contribute to the resistance of liver cancer to ICB,and combining TAN depletion with T cell immunotherapy synergistically increases antitumor efficacy.

HIV-Specific IL-2^+ and/or IFN-γ^+ CD8^+ T Cell Reponses during Chronic HIV-1 Infection in Former Blood Donors

Objective Conflicting data have been generated from previous studies to determine which kind of relationship exists between HIV-1 specific CD8 Tcell responses and HIV-1 viral load or CD4 count over the course of infection.In this study,153 HIV-1 infected LTNPs were enrolled to investigate the role of HIV-1 specific CD8 T-cell responses in chronic HIV-1 infection among HIV-1 infected former blood donors.Methods The patients were stratified into three groups according to CD4 count：CD4≥500 cells/μL;350 cells/μL≤CD4〈500 cells/μL;CD4〈350 cells/μL.PBMCs were isolated from the patients＇ anticoagulated blood samples.IL-2 and IFN-γ secretions of CD 8 T cells against 17 HIV-1 consensus B full peptide pools were analyzed by using ICS assay.Results An overall inverse correlation were observed between CD4 count and plasma viral load.Although no significant difference was observed during the comparisons of frequency/breadth of HIV-1 specific CD8 T cell responses,CD4 count stratification analysis showed that different correlation pattern existed in three strata：as for patients whose CD4 counts were less than 350 cells/μL,no significant correlations were identified between frequency/breadth of HIV-1 specific CD8 T cell responses and CD4 count/viral load;as for patients whose CD4 counts ranged from 350 cells /μL to 500 cells/μL,significant correlation was only observed between the response breadth of IL-2＋IFN-γ＋ CD8 T cells and CD4 count;however,as for patients whose CD4 counts were more than 500 cells/μL,direct correlations were identified between IL-2＋IFN-γ＋/IL-2＋/IFN-γ＋ CD8 T cells and viral load or CD4 count.Conclusions Universal consistent inverse correlation was only indentified between CD4 count and viral load.The relationship between HIV-1 specific CD8 T cell responses and CD4 count/viral load varied in different CD4 strata,which showed that better preserved CD4 T cells were correlated with better CD8 T cell functions.

Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV) infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified, including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host’s human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCV- specific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

TARGETED ACTIVATION OF CD_(8)^(+) CELLS AND INFECTION OF β_2-MICROGLOBULIN-DEFICIENT MICE FAIL TO CONFIRM A PRIMARY PROTECTIVE ROLE FOR CD_(8)￣(+) CELLS IN EXPERIMENTAL LEISHMANIASIS

CD8+ T cells play an important role in the immunologic control of intracellular pathogens,particularly viruses,Leishmania are obligate intracellular parasites of macrophages in the mammalian host,and previous studies using deletion of CD8+ cells by administration of mAb to infected animals have suggested a protective role for these cells.Two complementary approaches were used to define more carefully the role of CD8+ cells in leishmaniasis.In BALB/c mice susceptible to Leishmania major(L. major)infection, targeted activation of CD8+ cells was attempted by immunization with nonapeptides derived from the conserved major outer surface protein of the organism,8p63, that contained the consensus binding motif for MHC class 1 H-2kd molecules.Two of the nonapeptides induced CTL activity in subsequently infected BALB/c mice that could be elicited against p815 cells pulsed either with peptide or lysates of L.major.purified CD8+ T cells from immunized mice had elevated levels of IFN-γ mRNA transcripts as compared to unimmunized mice.Despite evidence for activation of CD8+ cells,none of the mice immunized with nine different peptides alone or in combination were protected from progressive disease. In a second series of experiments, β2-microglobulin deficient mice that lack CD8+ cells were infected with L. major and the course of infection monitored.These mice cured disease as'rapidly as β2-m +/- and +/+ littermates,and cure was associated with comparable levels of IFN-Y mRNA in the draining lymph node population. Neither of these approaches was able to confirm a substantive role for CD8+ T cells in the primary protective response to L.major.

Factors Associated with Sample Rejection for CD4+/CD8+ T Cell Count Analyses at the Kenyatta National Hospital Comprehensive Care Center Laboratory, Kenya

Background: The appropriate time to initiate antiretroviral therapy (ART) in HIV/AIDS patients is determined by measurement of CD4+/CD8+ T cell count. The CD4/CD8+ T cell count is also useful, together with viral load, in monitoring disease progression and effectiveness treatment regimens. Several factors may contribute to sample rejection during the CD4+/CD8+ T cells count, resulting in negative effects on patient management. Objective: Evaluate the causes for CD4+CD8+ T cell count sample rejection at the Kenyatta National Hospital Comprehensive Care Center Laboratory. Method: A retrospective cross-sectional study was conducted between 2018 and 2020. Data was obtained from the “rejected samples” for PartecR FlowCyp flow cytometry file. Designed data collection sheet was used for data capture. A total of 3972 samples were submitted for CD4+/CD8+ T cell count during the study period. Causes for sample rejection were numbered 1 to 12, each representing a reason for sample rejection. Number 1 was sub-categorized into clotted, hemolyzed, short-draw and lipemic. Data was analyzed using excel, and presented using tables, graphs and pie charts. Approval to conduct the study was obtained from KNH/UoN ERC. Results: In the study period, 81/3972 (2.0%) samples were rejected. Samples submitted more than 48 hours after collection were mostly rejected. Other factors included improper collection technique, delayed testing, patient identification error and incorrect use of vacutainer. A combination of clotted samples, specimen submission more than 48 hours caused the most frequent sample rejection, followed with combination of specimen submission more than 48 hours, delayed testing and delayed specimen processing. Together, clotted samples, incorrect vacutainer and poor specimen label caused the least sample rejection. Conclusion: Sample rejection rate for CD4/CD8+ T cell count was relatively low, and multiple factors contributed to rejection. However, improved quality assurance will enable more benefit to patients who seek this test in the laboratory.

Research progress on the role of immune cells in Brucella infection

Brucellosis is one of the most prevalent zoonoses in the world. Incidence of the disease has increased significantly in recent years and has seriously affected the health of human beings and the development of animal husbandry. The pathogenesis of brucellosis remains unclear. Current studies suggest that this disease may be related to changes in natural killer cells, dendritic cells, and macrophages in immune cell subsets. Brucellosis may be also related to T helper(Th) 1 cell/Th2 cell imbalance in the CD4^+ T cell subset, immunoregulation of regulatory T cells and Th17 cells, and the mechanism of action of CD8^+ T cell. This paper aims to review the research progress on these inherent immune cells, the CD4^+ T cell subset, and CD8^+ T cells in Brucella infection.

Development and optimization of a double antibody sandwich ELISA for the detection of goose T cell surface CD8α molecule

CD8, a glycoprotein on the surface of T cells, is involved in the defense against viral infection and plays significant roles in antigen presentation and in the antiviral immune response. CD8 is composed of two chains. Of these, the CD8α chain was chosen for the detection because it involved in both the CD8αα homodimer and the CD8αβ heterodimer. Here, we established a double antibody sandwich enzyme-linked immunosorbent assay（DAS-ELISA） for specific detection of goose CD8α（go CD8α）. The results showed that the optimal coated antibody and antigen dilutions were 1：50（the antibody titer was 1：12 800） and 1：32（0.3 ng m L^–1）, respectively, while the optimal capture antibody and horseradish peroxidase（HRP）-labelled goat anti-rabbit Ig G dilutions were 1：50（the antibody titer was 1：51 200） and 1：4 000（the antibody titer was 1：5 000）, respectively. The optimal blocking buffer was 5% bovine serum albumin（BSA）. The best incubating condition was overnight at 4℃, the best blocking time was 120 min and the best anti-capture antibody working time was 150 min. In addition, the minimum dose detectable by DAS-ELISA was 5×10^–3 ng m L^–1. Most importantly, go CD8α expression levels in goose spleen mononuclear cells（MNCs） post-Goose parvoviruse（GPV） infection were found to be significantly up-regulated using the DAS-ELISA method, which was consistent with previous results obtained using real-time quantitative PCR. In conclusion, the DAS-ELISA method reported here is a novel, specific technique for the clinical detection of go CD8α.