RECTAL IMMUNIZATION AGAINST SIV INFECTION

针对 SIV 感染的直肠免疫接种

• 批准号: 2004080
• 负责人: Thomas Lehner
• 金额: $ 10.31万
• 依托单位: U OF L UNTD MED/DENT SC/GUYS/ST THOMAS
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-11-01 至 1997-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2004080
• 关键词: HIV envelope protein gp160; Macaca mulatta; active immunization; antibody receptor; antiviral antibody; cellular immunity; disease /disorder model; drug delivery systems; enzyme linked immunosorbent assay; gut associated lymphoid tissue; helper T lymphocyte; immunoglobulin A; immunoglobulin G; intestinal mucosa; lymph nodes; lymphocyte proliferation; neutralizing antibody; polymerase chain reaction; postmortem; receptor binding; rectum /anus; secretory immune system; serology /serodiagnosis; simian immunodeficiency virus; viral vaccines

Rectal transmission of HIV is the most common route of infection during homosexual intercourse in developed countries, and anal sex increases the risk of male to female transmission in developing countries. The mechanism of protective immunity induced by rectal vaccination differs from that induced by systemic immunization. The objectives of this proposal are to develop an immunization strategy in non-human primates that will elicit 3 levels of immunity which match 3 phases of HIV infection (a) To induce rectal secretory IgA antibodies and cytotoxic T cells to prevent rectal infection by SIV. (b) To elicit regional lymph node proliferative and cytotoxic T cells and specific B cells to prevent the development of a reservoir of latency of the virus in these lymph nodes. (c) To induce specific serum neutralizing antibodies and circulating cytotoxic T cells, in order to prevent dissemination of the virus. The project has been designed to overcome a low degree of rectal immunity. This might be achieved (i) by increasing the binding affinity of the vaccine to two mucosal receptors; GM1 ganglioside and Fcgamma receptors. Recombinant envelope gp160, core p27 and reverse transcriptase will be used to link to cholera toxin subunit B (CT-B) and to IgG class of antibodies. (ii) The rectal associated lymphoid tissue will be augmented by gut, nasal or bronchial associated lymphoid tissue, through oral or nasal administration of the vaccine. The immunological changes involving antibodies and T cell functions will be assayed sequentially. IgA and IgG antibodies will be assayed by ELISA, using rectal washings, urine, serum and saliva. To overcome the unpredictable dilution factor inherent in collecting rectal washings, the IgA antibodies will be quantitated in terms of affinity purified antibody, and expressed as a percentage of total IgA concentration in rectal washings. T cell proliferative and cytotoxicity assays will be carried out with PBMC before and after each immunization, and at autopsy with iliac, mesenteric, and other lymph nodes, and spleen. T cell epitopes will be mapped by stimulating short term cell lines with overlapping peptides of the sequenced antigens and the resulting peptides will be applied to T cell cytotoxicity assays. Antibody forming B cells and cytotoxic T cells will be assayed directly by separating lymphocytes from the rectal tissue. The triple level of immunity to SIV in the rectal mucosa, regional lymph nodes and blood will then be tested by rectal challenge of macaques with live SIV. Pre-titrated stocks of well characterized SIVmac 32H and molecular clones will be used to challenge vaccinates by the rectal route. The macaques will be monitored for infection by virus isolation, PCR and seroconversion. Alternative vaccines will be tried in the SIV model, using cholera and salmonella vectors, in order to develop the most effective rectal immunity of SIV infection. These experiments should pave the way in the development of an effective strategy of rectal immunization, in preventing human transmission of HIV infection by the anal route.

直肠传播艾滋病毒是最常见的感染途径， 在发达国家，同性恋性交和肛交增加了 在发展中国家男性传播给女性的风险。 的 直肠接种诱导的保护性免疫机制不同 与全身免疫所引起的免疫力相比。 这一目标 建议在非人类灵长类动物中开发免疫策略 这将引发3个免疫水平，与艾滋病毒的3个阶段相匹配 感染（a）诱导直肠分泌型伊加抗体和细胞毒性T 细胞，以防止SIV直肠感染。 (b)引出局部淋巴 淋巴结增殖和细胞毒性T细胞和特异性B细胞，以防止 在这些淋巴中潜伏的病毒库的发展 结 (c)诱导特异性血清中和抗体， 循环细胞毒性T细胞，以防止传播的细胞毒性T细胞， 病毒 该项目旨在克服直肠癌的低度 免疫力 这可以通过（i）增加结合亲和力来实现 两种粘膜受体：GM 1神经节苷脂和Fc γ 受体。 重组包膜gp 160，核心p27和反向 转录酶将用于连接霍乱毒素亚单位B（CT-B）， IgG类抗体。 (ii)直肠相关淋巴组织 将通过肠道、鼻或支气管相关淋巴组织增强， 通过口服或鼻内注射疫苗。 涉及抗体和T细胞功能的免疫学变化将 按顺序测定。 伊加和IgG抗体将通过 ELISA，使用直肠冲洗液、尿液、血清和唾液。 克服 不可预测的稀释因素固有的收集直肠冲洗， 伊加抗体将根据亲和纯化的抗体进行定量。 抗体，并表示为总伊加浓度的百分比 直肠冲洗液。 T细胞增殖和细胞毒性测定将在 在每次免疫之前和之后以及在尸检时用PBMC进行 髂、肠系膜和其他淋巴结以及脾脏。 T细胞 表位将通过刺激短期细胞系来绘制， 测序抗原的重叠肽和所得肽 将应用于T细胞毒性测定。 抗体形成B细胞 通过分离淋巴细胞直接测定细胞毒性T细胞 从直肠组织中分离出来 免疫系统对SIV的三重免疫水平 直肠粘膜、局部淋巴结和血液将通过 用活的SIV对猕猴进行直肠攻击。 井的预滴定储备 表征的SIVmac 32 H和分子克隆将用于挑战 通过直肠途径接种疫苗。 这些猕猴将被监控 通过病毒分离、PCR和血清转化感染。 替代 疫苗将在SIV模型中进行试验，使用霍乱和沙门氏菌 载体，以发展SIV的最有效的直肠免疫 感染 这些实验应该为发展 直肠免疫是预防人类免疫的有效策略， 通过肛门途径传播艾滋病毒感染。