E COLI LT AS A RECTAL AND VAGINAL MUCOSAL ADJUVANT

该项目将验证口服佐剂大肠杆菌不耐热毒素(LT)可以安全有效地用于增强对人类直肠和阴道粘膜中HIV抗原的粘膜和系统免疫反应的假设。疫苗接种策略通过在直肠和生殖道分泌物中诱导持久的、高滴度的艾滋病毒特异性抗体，可以通过阻止病毒进入这些部位来防止艾滋病毒的性传播。目前的数据表明，局部免疫路线将是产生这些抗体以及粘膜中抗病毒T辅助(TH)细胞的最佳途径。然而，在人类中还没有发现能增强对直肠或阴道注射疫苗反应的粘膜佐剂。目的：确定LT在人体直肠和阴道的最大安全给药剂量，并确定与LT联合给药的HIV P55 Gag颗粒的免疫原性剂量。在直肠或阴道内使用从1-5杯不等的小剂量LT后，将对女性群体进行副作用评估。为了确认LT的摄取，局部分泌物将通过ELISA进行抗LT抗体的筛查。然后，对较小的妇女群体进行直肠和阴道免疫，接种最大安全LT剂量和250或500杯P55，以确认联合制剂也是安全的，并建立诱导局部分泌物中P55特异性抗体所需的直肠和阴道P55剂量。特异的目的是测试LT对经直肠或阴道联合给药的P55的系统和粘膜免疫反应以及免疫记忆发展的能力。比较P55单独免疫和P55联合LT免疫妇女的血清和局部及远端分泌物中抗P55抗体的水平。对TH1/TH2型反应的诱导将通过定量P55刺激的外周血单核细胞体外分泌的特异性Ig G亚类抗体和细胞因子来评估。记忆细胞的建立将通过使用[~3H]胸腺嘧啶核苷摄取试验测量血液中的淋巴增殖来评估，并通过测量P55增强直肠/阴道后产生的抗体来评估。这项研究将有助于了解粘膜佐剂在诱导局部和远端免疫反应中的作用，设计对性传播疾病产生保护性免疫的免疫策略，以及有希望的HIV疫苗亚单位成分的粘膜免疫原性。

This project will test the hypothesis that the oral adjuvant E. coli heat-labile toxin (LT) could be used safely and effectively for enhancing mucosal and systemic immune responses to HIV antigens administered in the rectal and vaginal mucosa of humans. Vaccination strategies that induce durable, high-titered HIV- specific antibodies in rectal and genital tract secretions could prevent sexual transmission of HIV by blocking viral entry at these sites. Current data suggests that local immunization routes would be optimal for generating these antibodies as well as antiviral T helper (TH) cells in the mucosa. However, mucosal adjuvants that augment responses to rectally- or vaginally- administered vaccines have not been identified in humans. Specific AIM I is to confirm uptake and determine the maximal safe dose of LT that can be administered in the rectum and vagina of humans, and to establish an immunogenic dose of HIV p55 gag particles that can be safely co-administered with LT. Groups of women will be evaluated for side effects after small graded doses of LT ranging from 1-5 mug are administered in the rectum or vagina. To confirm LT uptake, local secretions will be screened by ELISA for anti-LT antibodies. Smaller groups of women will then be rectally and vaginally immunized with both maximal safe LT doses and 250 or 500 mug p55 to confirm that the combined preparations are also safe and to establish the rectal and vaginal doses of p55 required for induction of p55-specific antibodies in local secretions. Specific AIM II is to test LT for its ability to enhance systemic and mucosal immune responses and development of immunological memory to p55 co-administered via rectal or vaginal routes. Levels of anti-p55 IgG and IgA antibodies induced in serum and both local and distal secretions of women immunized with p55 alone or p55 with LT will be compared. Induction of TH1/TH2-type responses will be evaluated by quantitating specific IgG subclass antibodies and cytokines secreted in vitro by p55-stimulated peripheral blood mononuclear cells. Memory cell establishment will be assessed by measuring lymphoproliferation in blood using [3H]thymidine uptake assays, and by measuring antibody generated after rectal/vaginal boosting with p55. This study will contribute to knowledge concerning effects of mucosal adjuvants on induction of both local and distal immune responses, design of immunization strategies which produce protective immunity against sexually-transmitted diseases, and mucosal immunogenicity of a promising HIV vaccine subunit component.