CD8 T cell response in a phase I study of therapeutic vaccination of advanced NSCLC with allogeneic tumor cells secreting endoplasmic reticulum-chaperone gp96-Ig-peptide complexes

Antigen containing, allogeneic cells secreting the genetically modified protein and peptide-chaperone gp96-Ig cross, prime and expand antigen specific CD8 T cells with therapeutic antitumor activity in mice. In a first in man phase I study, we now report the results of therapeutic vaccination of non-small cell lung cancer (NSCLC) patients with an established, allogeneic non-small cell lung adenocarcinoma cell line secreting gp96-Ig. Advanced NSCLC-patients stage IIIB or IV of any histological subtype were enrolled and treated with up to 36 vaccinations over the course of 18 weeks. Primary endpoint was safety, secondary endpoints tumor response and overall survival. Measurement of tumor antigen specific CD8 CTL responses is precluded by the lack of known NSCLC associated antigens. Therefore, we measured patient CD8 T cell-IFN-γ responses to allo-antigens of the vaccine cells as surrogate for tumor antigen specific CD8 CTL. In 7 of 18 treated patients tumor growth was stabilized, however none of the 18 patients had an objective tumor response by RECIST criteria. Of 15 patients evaluable for immune response, 11 responded to vaccination with more than twofold increase in CD8-IFN-γ frequency above baseline. These patients had a median survival time of 16.5 months. Four patients who had no CD8 response above base line had survival times from 2.1 to 6.7 months. Our data are consistent with the concept that generation of CD8 CTL by therapeutic vaccination may delay tumor growth and progression and mediate prolonged survival even in the absence of objective tumor responses. Further studies will be required to test this concept and promising result.

Advances in inducing adaptive immunity using cell-based cancer vaccines: clinical applications in pancreatic cancer

The incidence of pancreatic ductal adenocarcinoma(PDA) is on the rise, and the prognosis is extremely poor because PDA is highly aggressive and notoriously difficult to treat. Although gemcitabine- or 5-fluorouracil-based chemotherapy is typically offered as a standard of care, most patients do not survive longer than 1 year. Therefore, the development of alternative therapeutic approaches for patients with PDA is imperative. As PDA cells express numerous tumor-associated antigens that are suitable vaccine targets, one promising treatment approach is cancer vaccines. During the last few decades, cell-based cancer vaccines have offered encouraging results in preclinical studies. Cell-based cancer vaccines are mainly generated by presenting whole tumor cells or dendritic cells to cells of the immune system. In particular, several clinical trials have explored cell-based cancer vaccines as a promising therapeutic approach for patients with PDA. Moreover, chemotherapy and cancer vaccines can synergize to result in increased efficacies in patients with PDA. In this review, we will discuss both the effect of cell-based cancer vaccines and advances in terms of future strategies of cancer vaccines for the treatment of PDA patients.

Combinational adenovirus-mediated gene therapy and dendritic cell vaccine in combating well-established tumors

Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor suppressor genes. Central to all these therapies is the development of efficient vectors for gene therapy. By far, adenovirus （AdV）-mediated gene therapy is one of the most promising approaches, as has confirmed by studies relating to animal tumor models and clinical trials. Dendritic cells （DCs） are highly efficient, specialized antigen-presenting cells, and DC- based tumor vaccines are regarded as having much potential in cancer immunotherapy. Vaccination with DCs pulsed with tumor peptides, lysates, or RNA, or loaded with apoptotic/necrotic tumor cells, or engineered to express certain cytokines or chemokines could induce significant antitumor cytotoxic T lymphocyte （CTL） responses and antitumor immunity. Although both AdV-mediated gene therapy and DC vaccine can both stimulate antitumor immune responses, their therapeutic efficiency has been limited to generation of prophylactic antitumor immunity against re-challenge with the parental tumor cells or to growth inhibition of small tumors. However, this approach has been unsuccessful in combating well-established tumors in animal models. Therefore, a major strategic goal of current cancer immunotherapy has become the development of novel therapeutic strategies that can combat well-established tumors, thus resembling real clinical practice since a good proportion of cancer patients generally present with significant disease. In this paper, we review the recent progress in AdV-mediated cancer gene therapy and DC-based cancer vaccines, and discuss combined immunotherapy including gene therapy and DC vaccines. We underscore the fact that combined therapy may have some advantages in combating well-established tumors vis-a-vis either modality administered as a monotherapy.

T cell responses to hepatitis B surface antigen are detectable in non-vaccinated individuals

AIM: To evaluate, whether humoral hepatitis-B-vaccine non-responders also fail to mount a T cell response and to compare these results to normal vaccinees. METHODS: Fourty-seven health care employees were enrolled in this study including all available non- responders (n = 13) with an anti-HBsAg titer < 10 kU/L and all available low-responders (n = 12) with an anti- HBsAg titer < 100 kU/L. Also, 12 consecutive anti-HBsAg negative pre-vaccination subjects were enrolled as well as 10 subjects (+7 from the vaccinated group) with titers > 1000 kU/L as controls. PBMC from all subjects were analyzed by IFN-γ and IL-4 ELISPOT assays for the presence of hepatitis B surface antigen (HBsAg) reactive T cells. RESULTS: Non-responders and low-responders had no or only very limited T cell responses, respectively. Indi- viduals responding to vaccination with the induction of a high anti-HBsAg titer showed a strong T cell response after the third vaccination. Surprisingly, these individuals showed response even before the first vaccination. T cell response to control antigens and mitogens was similar in all groups. CONCLUSION: Our data suggest that there is no gen- eral immune deficiency in non-/low-responders. Thus, we hypothesize that the induction of anti-HBsAg re- sponses by vaccination is significantly dependent on the pre-existing T cell repertoire against the specific antigen rather than the presence of a general T cell defect.

Potent T cell Responses Induced by Single DNA Vaccine Boosted with Recombinant Vaccinia Vaccine

Plasmid DNA, an effective vaccine vector, can induce both cellular and humoral immune responses. However, plasmid DNA raises issues concerning potential genomic integration after injection. This issue should be considered in preclinical studies. Tiantan vaccinia virus (TV) has been most widely utilized in eradicating smallpox in China. This virus has also been considered as a successful vaccine vector against a few infectious diseases. Potent T cell responses through T-cell receptor (TCR) could be induced by three injections of the DNA prime vaccine followed by a single injection of recombinant vaccinia vaccine. To develop a safer immunization strategy, a single DNA prime followed by a single recombinant Tiantan vaccinia (rTV) AIDS vaccine was used to immunize mice. Our data demonstrated that one DNA prime/rTV boost regimen induced mature TCR activation with high functional avidity, preferential T cell Vβ receptor usage and high sensitivity to anti-CD3 antibody stimulation. No differences in T cell responses were observed among one, two or three DNA prime/rTV boost regimens. This study shows that one DNA prime/rTV boost regimen is sufficient to induce potent T cell responses against HIV.

Polyfunctional T Cell and Neutralizing Antibody Responses to ACAM2000TM Smallpox Vaccine Immunization in Primary-Vaccinated Individuals

Smallpox eradication was successful via prophylactic administration of live attenuated vaccinia virus. As a result of the discontinuation of the smallpox immunization program, many individuals are now susceptible to smallpox virus infection should it be used as a biological weapon. Presently, only individuals at high risk for exposure are required to receive smallpox vaccine, such as laboratory personnel that handle variola/vaccinia virus. This study endeavored to investigate a one-year period of vaccinia virus-specific T cell responses using polychromatic flow cytometry and neutralizing (Nt) antibody responses using plaque reduction neutralization test (PRNT) in individuals receiving primary immunization (n = 5) with ACAM2000TM smallpox vaccine. Functional and phenotypic profiles of vaccinia virus-specific T cell responses were characterized. Each single functional measurement {CD107a/b expression, production of interferon g (IFN-g), macrophage inflammatory protein 1b (MIP-1b), interleukin 2 (IL-2), and tumor necrosis factor a (TNF-a)} demonstrated that vaccinia virus-specific CD8+ T cells were functional at least one time point after vaccination (p ≤ 0.05). However, vaccinia virus-specific CD4+ T cells were functional only for MIP-1b production (p ≤ 0.05). Vaccinia virus-specific CD8+ T cells induced in these individuals showed increased polyfunctionality in at least 2 phenotypes relative to pre-vaccination (p ≤ 0.05). Although only three of five individuals (60%) showed positive Nt antibody (titer ≥ 20) at first month after vaccination, all five individuals (100%) demonstrated Nt antibody at 2 months, post-immunization. Interestingly, all vaccinees could retain the Nt antibody for 6 months after primary vaccination. In conclusion, ACAM2000TM smallpox vaccine induced both polyfunctional T cell-and Nt antibody-responses in primary immunized individuals.

T Regulatory Cells and BCG as a Vaccine against Tuberculosis: An Overview

Bacille Calmette Guerin (BCG), which has been used since 1921 as the only vaccine against tuber-culosis (TB), protects poorly, if at all, against pulmonary tuberculosis among adults in high incident developing countries. This failure has been attributed to the possible down modulating action of T regulatory cells (Tregs), which can be stimulated by environmental mycobacteria and expanded by BCG vaccination. Tregs induced at the site of BCG vaccination may interfere with protection against tuberculosis. This communication describes the contribution of Tregs towards dampening the efficacy of BCG and plausible approaches to countering this down modulating effect of Tregs. Probably, antigen specific inhibition of the local recruitment of Tregs whilst avoiding generalised disturbance of immune homeostasis could prove to be worthwhile. Alternatively, drugs with short half life may achieve more acceptable transient inhibition of Tregs function than the prolonged action of monoclonal antibodies. Evolving novel safe strategies is a challenge for developing a better anti TB vaccine.

Transgene IL-21-Engineered T Cell-Based Vaccine Potently Converts CTL Exhaustion via the Activation of the mTORC1 Pathway in Chronic Infection

CD8+ cytotoxic T lymphocyte (CTL) exhaustion is one of the major obstacles for the effectiveness of virus control in chronic infectious diseases. We previously generated novel ovalbumin (OVA)-specific 41BBL-expressing OVA-TEXO and human immunodeficiency virus (HIV-1) Gag-specific Gag-TEXO vaccines, inducing therapeutic immunity in wild-type C57BL/6 (B6) mice, and converting CTL exhaustion in recombinant OVA-specific adenovirus AdVOVA-infected B6 (AdVOVA-B6) mice with chronic infection. IL-21 cytokine plays an important role in controlling chronic infections. Therefore, in this study, we constructed recombinant transgene IL-21-expressing AdVIL-21, and generated IL-21-expressing OVA-TEXO/IL-21 and Gag-TEXO/IL21 vaccines, or control vaccines (OVA-TEXO/Null and Gag-TEXO/Null) by infecting OVA-TEXO and Gag-TEXO cells with AdVIL-21 or the control AdVNull, lacking transgene, and assessed their effects in B6 or AdVOVA-B6 mice. We demonstrate that both OVA-TEXO/IL-21 and control OVA-TEXO/Null vaccines are capable of converting CTL exhaustion in chronic infection. However, the OVA-TEXO/IL-21 vaccine more efficiently rescues exhausted CTLs by increasing stronger CTL proliferation and effector cytokine IFN-γ expression than the control OVA-TEXO/Null vaccine in AdVOVA-B6 mice with chronic infection, though both vaccines stimulated comparable OVA-specific CTL responses and protective immunity against OVA-expressing BL6-10OVA melanoma lung metastasis in wild-type B6 mice. In vivo, the OVA-TEXO/IL-21-stimulated CTLs more efficiently up-regulate phosphorylation of mTORC1-controlled EIF4E and expression of mTORC1- regulated T-bet molecule than the control OVA-TEXO/Null-stimulated ones. Importantly, the Gag-TEXO/IL21 vaccine induces stronger Gag-specific therapeutic immunity against established Gag-expressing BL6-10Gag melanoma lung metastases than the control Gag-TEXO/Null vaccine in chronic infection. Therefore, this study should have a strong impact on developing new therapeutic vaccines for patients with chronic infections.

The Tat Protein Enhances CTL Responses and Therapeutic Immunity of Gag-Specific Exosome-Targeted T Cell-Based Gag/Tat-Texo Vaccine in Transgenic HLA-A2 Mice

Human immunodeficiency virus type-1 (HIV-1) chronic infection causes millions of deaths each year. We previously developed a novel HIV-1 Gag-spe cific exosome (EXO)-targeted T cell-based vaccine (Gag-Texo) using ConAstimulated polyclonal CD8+T (ConA-T) cells armed with Gag-specific dendritic cell (DC)-released EXOs, and showed that Gag-Texo stimulated more efficient cytotoxic T lymphocyte (CTL) responses than DCs. Tat HIV-1 early regulatory protein possesses immunomodulatory and adjuvant properties. To enhance Gag-Texo immunogenicity, we generated Tat-engineered OVA/Tat Texo and Gag/Tat-Texo vaccines using ConA-T cells armed with EXOs release by DCs infected with recombinant OVA/Tat- and Gag/Tat-expressing adenoviruses (AdVOVA/Tat and AdVGag/Tat). We then assessed vaccination-stimulated CTL responses in naive mice, and therapeutic immunity in transgenic HLA-A2 mice bearing Gag/HLA-A2-expressing BL6-10OVA/A2 melanoma lung metastases. We demonstrate that the OVA/Tat-Texo vaccine enhances functional OVA-specific CTL responses, compared to the OVA-Texo vaccine, and broadens CTL responses recognizing the cryptic OVA epitope in C57BL/6 mice. Furthermore, we determine that the Gag/Tat-Texo not only stimulates more efficient CTL responses than Gag-Texo, but also induces enhanced therapeutic immunity. We show that, 30% of Gag/Tat-Texo-immunized mice are free of tumor lung-metastases, compared to all Gag-Texo-immunized mice displaying lung-metastasis. In addition, the average number of tumor lung metastases colonies (32/lung) in the Gag/Tat-Texo-immunized mice was also significantly lower than that (78/lung) observed in Gag-Texo-immunized mice. Taken together, this indicates that HIV-1 Gag/Tat-Texo capable of stimulating enhanced Gag-specific CTL responses and therapeutic immunity may become a new immunotherapeutic vaccine candidate for controlling virus in HIV-1 patients.

成人接种2剂新冠灭活疫苗12个月后T细胞免疫应答特点

目的评估成年人接种新型冠状病毒(SARS-CoV-2)灭活疫苗12个月后不同抗原特异性T细胞免疫应答的特点。方法解放军总医院第五医学中心2022年4-6月招募15名健康成年人,于接种2剂新冠灭活疫苗12个月后采集其静脉血标本,以基于多色流式细胞术的活化诱导标记法(AIM)检测SARS-CoV-2抗原特异性T淋巴细胞水平,并分析其记忆表型与亚群分化特点。结果成年人接种2剂灭活疫苗12个月后,90%以上个体可检测到Spike及Non-spike特异性CD4^(+)T细胞反应(S:14/15,P=0.0001;NS:15/15,P<0.0001);80%个体检测到Spike及Non-spike特异性CD8^(+)T细胞反应(S:12/15,P=0.0463;NS:12/15,P=0.0806)。抗原特异性CD4^(+)T细胞主要表现为中央记忆细胞(CM)、1型效应记忆细胞(EM1)记忆表型,以及1/17型辅助性T细胞(Th1/17)、2型辅助性T细胞(Th2)辅助表型。结论灭活疫苗接种后能诱导广泛且持久的抗原特异性CD4^(+)T细胞反应,可能是当前国内新型冠状病毒感染重症化比例较低的关键因素。

基于酵母β-葡聚糖载体的口服OVA疫苗(WGP-OVA疫苗)诱导体液免疫及抗原特异性T细胞免疫反应

目的:探讨口服WGP-OVA疫苗对C57BL/6小鼠体液免疫及抗原特异性T细胞免疫的诱导作用。方法:分别连续给予C57BL/6小鼠口服PBS、WGP及WGP-OVA 17 d后,使用LEGENDplexTM多因子流式检测试剂盒检测给药后小鼠血清中IgG1、IgG2a、IgG3及IgM的含量;HE染色比较各组小鼠脾脏淋巴小结的大小。取小鼠腹股沟淋巴结(ILNs)制备单细胞悬液,流式细胞仪(FACS)检测淋巴结内F4/80+巨噬细胞及F4/80+SIINFEKL+巨噬细胞比例,分析WGP-OVA对巨噬细胞在ILNs内的浸润及抗原提呈情况;同时通过MHC Tetramer染色检测抗原特异性CD8+T细胞比例,明确WGP-OVA疫苗对T细胞免疫的诱导作用。结果:与PBS组相比,WGP-OVA能显著诱导IgG1、IgG2a、IgG3及IgM的分泌,增大脾脏内淋巴小结。此外,口服WGPOVA疫苗能促进F4/80+巨噬细胞向淋巴结浸润,诱导巨噬细胞对OVA的抗原提呈,同时增加淋巴结内OVA特异性CD8+CTLs的数量。结论:口服WGP-OVA疫苗能诱导C57BL/6小鼠体液免疫及抗原特异性T细胞免疫反应。

Emergence of immunotherapy as a novel way to treat hepatocellular carcinoma

Tumor immunity proceeds through multiple processes, which consist of antigen presentation by antigen presenting cells(APCs) to educate effector cells and destruction by the effector cytotoxic cells. However, tumor immunity is frequently repressed at tumor sites. Malignantly transformed cells rarely survive the attack by the immune system, but cells that do survive change their phenotypes to reduce their immunogenicity. The resultant cells evade the attack by the immune system and form clinically discernible tumors. Tumor microenvironments simultaneously contain a wide variety of immune suppressive molecules and cells to dampen tumor immunity. Moreover, the liver microenvironment exhibits immune tolerance to reduce aberrant immune responses to massively-exposed antigens via the portal vein, and immune dysfunction is frequently associated with liver cirrhosis, which is widespread in hepatocellular carcinoma(HCC) patients. Immune therapy aims to reduce tumor burden, but it is also expected to prevent non-cancerous liver lesions from progressing to HCC, because HCC develops or recurs from noncancerous liver lesions with chronic inflammatory states and/or cirrhosis and these lesions cannot be cured and/or eradicated by local and/or systemic therapies. Nevertheless, cancer immune therapy should augment specific tumor immunity by using two distinct measures: enhancing the effector cell functions such as antigen presentation capacity of APCs and tumor cell killing capacity of cytotoxic cells, and reactivating the immune system in immune-suppressive tumor microenvironments. Here, we will summarize the current status and discuss the future perspective on immune therapy for HCC.

Relationship between T-lymphocyte cytokine levels and sero-response to hepatitis B vaccines

AIM: To investigate the cellular defects by analyzing the (Th1/Th2) cytokine levels in vaccine responders and non-responders. METHODS: Peripheral blood mononuclear cell (PBMC) from responders and non-responders were stimulated with or with out recombinant HBsAg or PHA. Broad spectrum of cytokines viz (Th1) IFN-γ, IL-2, TNF-α, IL-12 and (Th2) IL-10, IL-4 were measured after in vitro stimulation with recombinant HBsAg and were compared with respective antibody titers. RESULTS: A significant decrease (P = 0.001) in Th1 and Th2 cytokines namely, IL-2, INF-γ, TNF-α and IL-10in non-responders was observed. The level of IL-4 was not significant between the three groups. Furthermore, despite a strong Th1 and Th2 cytokine response, the level of IL-12 was elevated in high-responders compared to other groups (P = 0.001) and demonstrated a positive correlation with anti-HBs titers and Th1 cytokine response. CONCLUSION: Our findings suggest that unrespon-siveness to recombinant hepatitis B vaccines (rHB) is multifactorial, including specific failure of antigen presentation or the lack of both T helper Th1 and Th2 response.

Depletion of CD25^+CD4^+T cells (Tregs) enhances the HBV-specific CD8^+ T cell response primed by DNA immunization

AIM: Persistent hepatitis B virus (HBV) infection is characterized by a weak CD8+ T cell response to HBV. Immunotherapeutic strategies that overcome tolerance and boost these suboptimal responses may facilitate viral clearance in chronically infected individuals. Therefore, we examined whether CD25+CD4+ regulatory T (Treg) cells might be involved in a inhibition of CD8+T cell priming or in the modulation of the magnitude of the 'peak' antiviral CD8+ T cell response primed by DNA immunization. METHODS: B10.D2 mice were immunized once with plasmid pCMV-S. Mice received 500 μg of anti-CD25 mAb injected intraperitoneally 3 d before DNA immunization to deplete CD25+ cells. Induction of HBV-specific CD8+ T cells in peripheral blood mononuclear cells (PBMCs) was measured by S28-39 peptide loaded DimerX staining and their function was analyzed by intracellular IFN-γ staining. RESULTS: DNA immunization induced HBV-specific CD8+ T cells. At the peak T cell response (d 10), 7.1±2.0% of CD8+ T cells were HBV-specific after DNA immunization, whereas 12.7±3.2% of CD8+ T cells were HBV-specific in Treg-depleted mice, suggesting that DNA immunization induced more antigen-specific CD8+ T cells in the absence of CD25+ Treg cells (n = 6, P<0.05). Similarly, fewer HBV specific memory T cells were detected in the presence of these cells (1.3±0.4%) in comparison to Treg-depleted mice (2.6±0.9%) on d 30 after DNA immunization (n - 6, P<0.01). Both IFN-γ production and the avidity of the HBV-specific CD8+ T cell response to antigen were higher in HBV-specific CD8+ T cells induced in the absence of Treg cells. CONCLUSION: CD25+ Treg cells suppress priming and/or expansion of antigen-specific CD8+ T cells during DNA immunization and the peak CD8+ T cell response is enhanced by depleting this cell population. Furthermore, Treg cells appear to be involved in the contraction phase of the CD8+ T cell response and may affect the quality of memory T cell pools. The elimination of Treg cells or their inhibition may be important in immunotherapeutic strategies to control HBV infection by inducing virus-specific cytotoxic T lymphocyte responses in chronically infected subjects.

Activation and dramatically increased cytolytic activity of tumor specific T lymphocytes after radio-frequency ablation in patients with hepatocellular carcinoma and colorectal liver metastases

AIM： To assess if a specific cytotoxic T cell response can be induced in patients with malignant liver tumors treated with radio-frequency ablation （RFA）. METHODS： Six Patients with liver metastases of colorectal cancer and 6 with hepatocellular carcinoma （HCC） underwent RFA. Blood was sampled before, 4 and 8 wk after RFA. Test antigens were autologous liver and tumor lysate obtained from each patient by biopsy. Peripheral T cell activation was assessed by an interferon gamma （IFNγ） secretion assay and flow cytometry. T cells were double-stained for CD4/CD8 and IFNγ to detect cytotoxic T cells. The ratio of IFNγ positive and IFNγ negative T cells was determined as the stimulation index （SI）. To assess cytolytic activity, T cells were co-incubated with human CaCo colorectal cancer and HepG2 HCC cells and release of cytosolic adenylate kinase was measured by a luciferase assay. RESULTS： Before RFA SI was 0.021 （±0.006） for CD4^＋ and 0.022 （± 0.004） for CD8^＋T cells against nonmalignant liver tissue and 0.018 （± 0.005） for CD4^＋ and 0.021 （± 0.004） for CD8^＋ cells against autologous tumor tissue. Four weeks after RFA SI against tumor tissue increased to 0.109 （± 0.005） for CD4＋ and 0.11 （± 0.012） for CD8＋ T cells against HCC, and to 0.115 （± 0.031） for CD4^＋ and 0.15 （± 0.02） for CD8^＋ cells for colorectal metastases （P 〈 0.0001）. No increased SI was observed with nonmalignant tumor tissue at all time points. Before RFA cytolytic activity against the respect（ve cancer cells was low with 2.62 （± 0.37） relative luminescence units （RLU）, but rose more than 100 fold 4 and 8 wk after RFA. Spontaneous release was 〈 2% of maximum release in all experiments. CONCLUSION： Patients with primary and secondary tumors of the liver show a significant tumor-specific cytotoxic T-cell stimulation with a dramatically increased tumor specific cytolytic activity of CD8^＋ T cells after RFA.

Immunotherapy for advanced or recurrent hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is associated with high morbidity and mortality,and is prone to intra-and extrahepatic metastasis due to the anatomical and functional characteristics of the liver.Due to the complexity and high relapse rate associated with radical surgery or radiofrequency ablation,immune checkpoint inhibitors(ICIs)are increasingly being used to treat HCC.Several immunotherapeutic agents,along with their combinations,have been clinically approved to treat advanced or recurrent HCC.This review discusses the leading ICIs in practice and those currently undergoing randomized phase 1-3 trials as monotherapy or combination therapy.Furthermore,we summarize the rapidly developing alternative strategies such as chimeric antigen receptor-engineered T cell therapy and tumor vaccines.Combination therapy is a promising potential treatment option.These immunotherapies are also summarized in this review,which provides insights into the advantages,limitations,and novel angles for future research in establishing viable and alternative therapies against HCC.

T细胞免疫反应载体疫苗在人类疾病预防和治疗中的应用

人类疾病,特别是传染病和癌症,对公共卫生安全和全球经济构成前所未有的挑战。预防和治疗性疫苗的开发是应对人类疾病的优先对策。本文综述了疫苗载体的免疫学原理、T细胞载体疫苗设计策略及疫苗研究进展,为新型疫苗的设计提供新的思路。T细胞可以在机体发生感染后分化成不同的效应T细胞群,它们可以起到清除病原体的作用,关于效应T细胞功能和机制的研究对于设计能够引发基于T细胞免疫的疫苗至关重要。目前很多病毒(例如HIV、HCMV感染)和肿瘤疫苗的研发都侧重于T细胞类疫苗,在所有疫苗种类中,激活T细胞免疫反应的载体疫苗具有显著优势。许多来源的载体,包括病毒载体、细菌载体和核酸载体,它们在抗原提呈能力、免疫原性和保护效力方面都有良好的表现。此外,还总结了T细胞载体疫苗设计的策略,包括确定适当的抗原提呈途径和载体递送途径、确保生物安全性、如何选择合适的疫苗的载体、各种载体疫苗的优缺点等,尤其是mRNA疫苗在应对新冠疫情中发挥了重要的作用。疫苗载体的技术进步将会加速新型疫苗的研发,并且能促进人们对突发公共卫生事件的应对。

Mucosal COVID-19 vaccines:Risks,benefits and control of the pandemic

Based on mucosal immunization to promote both mucosal and systemic immune responses,next-generation coronavirus disease 2019(COVID-19)vaccines would be administered intranasally or orally.The goal of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines is to provide adequate immune protection and avoid severe disease and death.Mucosal vaccine candidates for COVID-19 including vector vaccines,recombinant subunit vaccines and live attenuated vaccines are under development.Furthermore,subunit protein vaccines and virus-vectored vaccines have made substantial progress in preclinical and clinical settings,resulting in SARS-CoV-2 intranasal vaccines based on the previously successfully used nasal vaccines.Additional to their ability to trigger stable,protective immune responses at the sites of pathogenic infection,the development of‘specific’mucosal vaccines targeting coronavirus antigens could be an excellent option for preventing future pandemics.However,their efficacy and safety should be confirmed.

Construction of HA-1-DC Nucleic-acid Vaccine and Induction of Specific Cytotoxic T Lymphocytes

An HA-1-DC nucleic-acid vaccine was constructed to induce anti-leukemia effect after hematopoietic stem cell transplantation (HSCT). DCs were generated from HSCT donors in vitro, and its immunologic activity was assayed by using flow cytometry and mixed lymphocytes reaction. HA-1 gene was electroporated into the cultured DCs to construct a DC nucleic-acid vaccine. After transfection for 48 h, the expression of HA-1 protein could be detected by using Western blot. The DCs were cultured with syngenic lymphocytes to induce specific cytotoxic T lymphocytes (CTLs). The cytoxicity of the CTLs was detected by LDH assay. The results showed that The DCs derived from peripheral blood monocytes (PBMCs) expressed the phenotype of DCs, and were effective in stimulating proliferation of the allogenic lymphocytes. After electroporating for 48-h, HA-1 protein was detected by using Western blot. The cytotoxity of inducing CTLs was higher than the control group. It was suggested that minor histocompatibility antigen HA-1 could be considered as a target of immunotherapy against leukemia after HSCT.