人类免疫缺陷病毒疫苗的研究进展

人类免疫缺陷病毒疫苗是控制艾滋病的最佳方法,动物模型证实该病毒疫苗是可行的。人类免疫缺陷病毒中和抗体可达到足够高的水平以预防该病毒感染,但有型特异性,人类免疫缺陷病毒特异性细胞毒T淋巴细胞不能单独预防该病毒感染,但能将病毒血病控制在低水平,目前,人们研究重点集中于病毒特异性抗性体和T细胞反应。现有疫苗尚不能诱导对原发性病毒株具有广泛中和能力的抗体。然而,重组痘病毒疫苗和DNA疫苗提示细胞毒T淋巴细胞反应对来自不同进化分支的原发病毒株有广泛的交叉反应力,人们需找到新的免疫原来诱导中和抗体,以取得最佳细胞毒T淋巴细胞反应。     

人类免疫缺陷病毒重组载体疫苗的研究进展

重组载体疫苗是目前人类免疫缺陷病毒疫苗的研究热点,近几年来不仅在病毒载体和细菌载体选用的种类方面有了新的突破,而且对载体疫苗的组合免疫策略和最佳免疫的选用方面已有全新的认识。本文就用于该病毒重组疫苗的病毒载体(包括痘病毒、α病毒、仙台病毒、甲型流感病毒、腺病毒、狂犬病病毒、疱疹性口炎病毒和单纯疱疹病毒载体)以及细菌载体(包括卡介苗、李斯特单胞茵、沙门茵和布氏杆菌载体)等的研究进展进行综述。     

人类免疫缺陷病毒黏膜疫苗

在以往的20年间,有关发展艾滋病疫苗的研究曾经进行了大量的工作,但进展不大,通常诱生基于抗包膜抗体的疫苗效果并不理想。目前一般认为,细胞免疫应答,特别是CD8细胞毒性T淋巴细胞(CTL)／抑制细胞和CD4辅助性T淋巴细胞在人类免疫缺陷病毒的控制上是必需的。因此能诱生细胞免疫应答的疫苗在控制人类免疫缺陷病毒的播散上至关重要。本文阐述了有关黏膜疫苗的理论、艾滋病黏膜疫苗的种类以及经口免疫耐受性问题,并提出艾滋病应当视为一种自身免疫病。故抗炎症或免疫抑制药物应用似有其可取之处。     

人类免疫缺陷病毒疫苗基础研究新进展

目前人类免疫缺陷病毒感染在全球呈迅速上升趋势,严重威胁着人类的健康和生命,研制安全、高效的疫苗是控制其蔓延的有效措施。本文就疫苗研制过程中存在于抗体免疫、T细胞免疫方面亟待解决的诸多问题以及相应的研究进展进行综述。     

抗人类免疫缺陷病毒广谱中和抗体与疫苗设计

自发现人类免疫缺陷病毒1型（HIV-1）30年来,科学家们不断探索有效的HIV-1疫苗,但至今效果不理想。由于“精英患者”的广谱中和血清能起到有效的抗病毒作用,研究人员希望通过对体液保护免疫机制的研究,推动疫苗的设计和优化,为尽早研发成功HIV疫苗提供关键理论和技术支撑。近几年来,由于技术的突破和改进,从HIV感染者中分离获得广谱中和抗体的概率和数量大大提高。本文针对近几年来分离的有代表性的广谱中和抗体,根据其不同的识别位点分为四大类进行详细介绍,并总结了从研究广谱中和抗体中所获得的疫苗设计创新思路与启示。     

融合表达小鼠IgG2b-Fc可增强人类免疫缺陷病毒1型Gag DNA疫苗的免疫原性

为阐明小鼠IgG2b-Fc对DNA疫苗免疫原性的增强作用,首先构建表达人类免疫缺陷病毒1型(human immunodeficiency virus type 1,HIV-1)CN54Gag基因的DNA疫苗及表达Gag与小鼠IgG2b-Fc融合基因的DNA疫苗,限制性酶切和DNA测序结果表明这两个疫苗均构建成功,蛋白免疫印迹结果也显示其正确表达。然后,利用上述DNA疫苗接种C57BL/6小鼠,比较两个DNA疫苗所诱导的特异性体液免疫反应和特异性细胞免疫反应。结果显示,融合表达小鼠IgG2b-Fc对特异性细胞免疫和体液免疫反应均有增强作用,但只有对特异性体液免疫反应的增强作用有统计学意义。     

北京地区部分人类免疫缺陷病毒基因型分析

我国于1985年发现第1例AIDS患者，据估计到2001年底我国艾滋病病毒(Human immunodeficiency viruses，HrV)感染者和患者累计数已达84万人，而且我国艾滋病的传播呈快速增长的态势，2001年报告艾滋病病毒感染数较上年增长了58％。HIV主要通过静脉吸毒、输血或使用血液制品以及不良性行     

人类免疫缺陷病毒辅助受体的研究进展

人类免疫缺陷病毒（ＨＩＶ）进入靶细胞需要ＣＤ４受体及辅助受体的参与,不同的ＨＩＶ株进入靶细胞需不同的辅助受体,亲Ｔ细胞ＨＩＶ株进入靶细胞需融合因子辅助,而亲巨噬细胞ＨＩＶ株进入靶细胞则需另一种辅助受体ＣＣ－ＣＫＲ－５辅助受体的发现,为研究ＨＩＶ的致病机制及艾滋病的治疗提供新的方向。     

The human immunodeficiency virus preventive vaccine research at the French National Agency for acquired immunodeficiency syndrome research

The human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic is of unprecedented gravity and is spreading rapidly, notably in the most disadvantaged regions of the world. The search for a preventive vaccine is thus an absolute priority. For over 10 years the French National Agency for AIDS research (ANRS) has been committed to an original program combining basic science and clinical research. The HIV preventive vaccine research program run by the ANRS covers upstream research for the definition of immunogens, animal models, and clinical research to evaluate candidate vaccines. Most researchers in 2004 believe that it should be possible to obtain partial vaccine protection through the induction of a strong and multiepitopic cellular response. Since 1992, the ANRS has set up 15 phases I and II clinical trials in order to evaluate the safety and the capacity of the candidate vaccines for inducing cellular immune responses. The tested candidate vaccines were increasingly complex recombinant canarypox viruses (Alvac) containing sequences coding for certain viral proteins, utilized alone or combined with other immunogens (whole or truncated envelope proteins). ANRS has also been developing an original strategy based on the utilization of lipopeptides. These comprise synthetic fragments of viral proteins associated with lipids that facilitate the induction of a cellular immune response. These approaches promptly allowed the assessment of a prime-boost strategy combining a viral vector and lipopeptides.     

Use of simian immunodeficiency virus for vaccine research

Rhesus monkeys were immunized with purified, disrupted, noninfectious simian immunodeficiency virus (SIV) in adjuvant induced SIV neutralizing antibodies. Two of six previously vaccinated macaques were protected against infection when challenged with 200-1,000 animal infectious doses of uncloned, pathogenic SIV and both have remained free of signs of virus infection for 19 and 30 months. Prior vaccination appeared to be of benefit in decreasing the virus load and in delaying the onset of AIDS in animals that became infected. Nonetheless, two of four previously vaccinated monkeys that became infected following challenge eventually developed AIDS and died 505 and 538 days after infection. Thus, for a vaccine to be truly effective against AIDS, it may have to protect absolutely against initial infection.     

Kunjin virus replicon vectors for human immunodeficiency virus vaccine development

We have previously demonstrated the ability of the vaccine vectors based on replicon RNA of the Australian flavivirus Kunjin (KUN) to induce protective antiviral and anticancer CD8+ T-cell responses using murine polyepitope as a model immunogen (I. Anraku, T. J. Harvey, R. Linedale, J. Gardner, D. Harrich, A. Suhrbier, and A. A. Khromykh, J. Virol. 76:3791-3799, 2002). Here we showed that immunization of BALB/c mice with KUN replicons encoding HIV-1 Gag antigen resulted in induction of both Gag-specific antibody and protective Gag-specific CD8+ T-cell responses. Two immunizations with KUNgag replicons in the form of virus-like particles (VLPs) induced anti-Gag antibodies with titers of > or =1:10,000. Immunization with KUNgag replicons delivered as plasmid DNA, naked RNA, or VLPs induced potent Gag-specific CD8+ T-cell responses, with one immunization of KUNgag VLPs inducing 4.5-fold-more CD8+ T cells than the number induced after immunization with recombinant vaccinia virus carrying the gag gene (rVVgag). Two immunizations with KUNgag VLPs also provided significant protection against challenge with rVVgag. Importantly, KUN replicon VLP vaccinations induced long-lasting immune responses with CD8+ T cells able to secrete gamma interferon and to mediate protection 6 to 10 months after immunization. These results illustrate the potential value of the KUN replicon vectors for human immunodeficiency virus vaccine design.     

Cytotoxic T-lymphocyte escape monitoring in simian immunodeficiency virus vaccine challenge studies

Several vaccine studies have ameliorated disease progression in simian-human immunodeficiency virus (SHIV) infections. The successes of these vaccines have been largely attributed to protective effects of cytotoxic T-lymphocyte (CTL) responses, although the precise correlates of immune protection remain poorly defined. It is now well established that vigorous CTL and antibody responses can rapidly select for viral escape variants after HIV and SIV infection. Here we suggest that viral variation analyses should be performed on viruses derived from vaccinated, SIV-, or SHIV-challenged animals as a routine component of vaccine evaluation to determine the contribution of immune responses to the success (or failure) of the vaccine regimen. To illustrate the importance of escape analysis, we show that rapid emergence of escape variants postchallenge contributed to the failure of a DNA prime/MVA boost vaccine regimen encoding SIV Tat.     

In vitro antigen challenge of human antibody libraries for vaccine evaluation: the human immunodeficiency virus type 1 envelope.

Human antibody responses, or versions thereof, can be cloned as phage display libraries. In vaccine evaluation, the possibility therefore exists of challenging the human response in vitro, rather than in vivo, in order to assist in establishing the most promising vaccine leads. The characteristics of the antibodies retrieved directly indicate the strengths and weaknesses of the vaccine at the molecular level. We applied this approach to compare recombinant and native human immunodeficiency virus type 1 envelope preparations. We conclude that recombinant gp160, gp140, and, to a lesser extent, gp120 present epitopes around the CD4 binding site in a conformation different from that of the native multimer and contrary to expected vaccine requirements. Antibodies to the potently neutralizing b12 epitope were selected preferentially from an immune library by purified human immunodeficiency virus type 1 virions. This suggests that b12 is a major epitope on the virions, in contrast to recombinant envelope preparations, in which related, weakly neutralizing epitopes predominate. Although the majority of virions in the preparation used are expected to be noninfective, it appears that they predominantly express a native envelope configuration and would be able to elicit potent neutralizing antibodies.     

Evidence for recombination of live, attenuated immunodeficiency virus vaccine with challenge virus to a more virulent strain

Live, attenuated immunodeficiency virus vaccines, such as nef deletion mutants, are the most effective vaccines tested in the simian immunodeficiency virus (SIV) macaque model. In two independent studies designed to determine the breadth of protection induced by live, attenuated SIV vaccines, we noticed that three of the vaccinated macaques developed higher set point viral load levels than unvaccinated control monkeys. Two of these vaccinated monkeys developed AIDS, while the control monkeys infected in parallel remained asymptomatic. Concomitant with an increase in viral load, a recombinant of the vaccine virus and the challenge virus could be detected. Therefore, the emergence of more-virulent recombinants of live, attenuated immunodeficiency viruses and less-aggressive wild-type viruses seems to be an additional risk of live, attenuated immunodeficiency virus vaccines.     

Dominant induction of vaccine antigen-specific cytotoxic T lymphocyte responses after simian immunodeficiency virus challenge

Cytotoxic T lymphocyte (CTL) responses are crucial for the control of human and simian immunodeficiency virus (HIV and SIV) replication. A promising AIDS vaccine strategy is to induce CTL memory resulting in more effective CTL responses post-viral exposure compared to those in natural HIV infections. We previously developed a CTL-inducing vaccine and showed SIV control in some vaccinated rhesus macaques. These vaccine-based SIV controllers elicited vaccine antigen-specific CTL responses dominantly in the acute phase post-challenge. Here, we examined CTL responses post-challenge in those vaccinated animals that failed to control SIV replication. Unvaccinated rhesus macaques possessing the major histocompatibility complex class I haplotype 90-088-Ij dominantly elicited SIV non-Gag antigen-specific CTL responses after SIV challenge, while those induced with Gag-specific CTL memory by prophylactic vaccination failed to control SIV replication with dominant Gag-specific CTL responses in the acute phase, indicating dominant induction of vaccine antigen-specific CTL responses post-challenge even in non-controllers. Further analysis suggested that prophylactic vaccination results in dominant induction of vaccine antigen-specific CTL responses post-viral exposure but delays SIV non-vaccine antigen-specific CTL responses. These results imply a significant influence of prophylactic vaccination on CTL immunodominance post-viral exposure, providing insights into antigen design in development of a CTL-inducing AIDS vaccine.     

中国蝙蝠携带狂犬病毒研究进展

狂犬病(Rabies),是由狂犬病毒(Rabies Virus,RV)引起的人和所有哺乳动物的急性致死性中枢神经系统的自然疫源性疾病.该病呈全球性分布、病死率高,引起学者们对病原鉴定、免疫防治等的广泛研究,并取得了重大进展.研究表明,蝙蝠是多种人兽共患疾病病毒的储存宿主,因此,蝙蝠携带狂犬病毒的调查研究引起广大学者们的广泛关注,蝙蝠在我国物种丰富,分布广泛,作为很多病毒的可能自然宿主,其感染携带RV的流行病学数据尚未可知.本文对我国蝙蝠的种类、分布以及蝙蝠作为狂犬病毒自然宿主的研究进展进行了综述,为广大学者的进一步相关研究提供参考依据.