STRATEGIES FOR INDUCTION OF MUCOSAL IMMUNITY TO HIV

诱导 HIV 粘膜免疫的策略

• 批准号: 3548046
• 负责人: GREGORY R HARRIMAN
• 金额: $ 24.39万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-10 至 1995-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3548046
• 关键词: AIDS; AIDS vaccines; B lymphocyte; HIV envelope protein gp120; HIV infections; cell mediated cytotoxicity; cholera toxin; cooperative study; cytotoxic T lymphocyte; enzyme linked immunosorbent assay; hemagglutinin; human immunodeficiency virus; immunologic memory; immunomodulators; laboratory mouse; neutralizing antibody; oral administration; rectum /anus; reproductive system; secretory immune system; tissue /cell culture; virus antigen

WHO estimates that 75% of the cases of HIV infection worldwide occur as a result of sexual intercourse. Thus, development of a vaccine against HIV capable of conferring protective mucosal immunity, and especially local genital immunity, will be crucial for control of this epidemic. The objective of this project will be to identify an oral immunization regimen, using small animals (mice) as a model, which is likely to confer effective, long-lasting and protective mucosal immunity against HIV infection. This objective will be achieved through the following specific aims. 1) Determine an optimal oral adjuvant / HIV immunogen regimen. This question will be addressed by orally immunizing mice with combinations of three HIV subunit immunogens (gp120 protein, a peptide representing the primary neutralizing determinant on gp120 and tat protein) and three oral adjuvants (cholera toxin, iscoms and microspheres) in different doses and with different immunization regimens. Secretory antibody responses, by ELISA and ELISPOT, will be used to measure the mucosal immune response to these regimens. 2) Determine the ability of secreted antibodies to neutralize HIV. It will be important to determine whether the oral immunization regimens employed are capable of generating neutralizing antibodies to HIV. To determine this, secreted antibodies will be assayed in vitro for HIV virus neutralization (prevention of p24 expression and viral cytopathic effects) and inhibition of cell to cell virus transmission. 3) Determine whether cytotoxic responses (CTL and ADCC) to HIV can be generated in mucosal tissues after oral immunization. Cytotoxic T cells against HIV are likely to play a key role in protective mucosal immunity to HIV. Therefore, lymphocytes from mucosal tissues will be tested for CTL and ADCC activity using in vitro assays with HIV immunogen-expressing target cells. 4) Determine the ability of oral immunization to generate a local mucosal immune response to HIV. Local mucosal immune responses in the genital tract or rectum to HIV will be assessed by measuring antibodies to HIV (including neutralizing antibodies) in secretions from these sites. 5) Determine the duration of secretory antibody responses to HIV and the length of memory B and T cell responses. For an oral vaccine to be effective, antibodies in secretions must persist for long periods of time. Orally immunized mice will have secretions collected at various, intervals, up to 12 months after immunization, and assayed for antibodies to HIV. Memory responses will be assessed by collecting lymphocytes from mucosal tissues at various time points after oral immunization and assaying for in vitro responses to HIV antigens. 6) Determine whether oral immunization with HIV immunogens results in oral tolerance to these immunogens. This will be evaluated by systemically reimmunizing mice which have previously been orally immunized with the same HIV immunogen and evaluating the subsequent systemic immune response (ie. serum antibody response and cytotoxicity).

世界卫生组织估计，全世界 75% 的艾滋病毒感染病例是通过 性交的结果。 因此，开发针对 HIV 的疫苗 能够赋予保护性粘膜免疫，特别是局部免疫 生殖器免疫对于控制这种流行病至关重要。 这 该项目的目标是确定口服免疫方案， 使用小动物（小鼠）作为模型，这可能会赋予有效的、 针对艾滋病毒感染的持久和保护性粘膜免疫。 这 目标将通过以下具体目标来实现。 1） 确定最佳口服佐剂/HIV 免疫原方案。 这个问题 将通过使用三种 HIV 组合口服免疫小鼠来解决 亚基免疫原（gp120 蛋白，一种代表初级免疫原的肽） gp120 和 tat 蛋白的中和决定簇）和三种口服佐剂 （霍乱毒素、iscom 和微球）以不同剂量和 不同的免疫方案。 分泌性抗体反应，通过 ELISA 和 ELISPOT，将用于测量对这些的粘膜免疫反应 治疗方案。 2) 测定分泌抗体的中和能力 艾滋病病毒。 确定是否口服免疫接种很重要 所采用的治疗方案能够产生针对 HIV 的中和抗体。 为了确定这一点，将在体外对分泌的抗体进行 HIV 检测 病毒中和（预防 p24 表达和病毒细胞病变 效应）和抑制细胞间病毒传播。 3）确定 是否可以产生针对 HIV 的细胞毒性反应（CTL 和 ADCC） 口服免疫后的粘膜组织。 对抗 HIV 的细胞毒性 T 细胞是 可能在艾滋病毒的保护性粘膜免疫中发挥关键作用。 因此，将检测来自粘膜组织的淋巴细胞的CTL和ADCC 使用表达 HIV 免疫原的靶细胞进行体外测定的活性。 4) 测定口服免疫产生局部粘膜的能力 对艾滋病毒的免疫反应。 生殖器局部粘膜免疫反应 通过测量 HIV 抗体来评估消化道或直肠对 HIV 的感染情况 （包括中和抗体）在这些位点的分泌物中。 5） 确定分泌性抗体对 HIV 反应的持续时间和 B 细胞和 T 细胞反应的记忆长度。 对于口服疫苗 为了有效，分泌物中的抗体必须持续很长时间。 口服免疫的小鼠将以不同的时间间隔收集分泌物， 免疫后长达 12 个月，并检测 HIV 抗体。 通过从粘膜收集淋巴细胞来评估记忆反应 口服免疫后不同时间点的组织并检测 对 HIV 抗原的体外反应。 6）确定是否口服免疫 与 HIV 免疫原结合导致对这些免疫原的口服耐受。 这 将通过对先前已免疫过的小鼠进行系统性重新免疫来进行评估 已口服相同的 HIV 免疫原并评估 随后的全身免疫反应（即血清抗体反应和 细胞毒性）。