E COLI LT AS A RECTAL AND VAGINAL MUCOSAL ADJUVANT

该项目将测试口服佐剂大肠杆菌热不稳定毒素（LT）可以安全有效地用于增强人类直肠和阴道粘膜对HIV抗原的粘膜和全身免疫反应的假设。在直肠和生殖道分泌物中诱导持久的、高滴度的HIV特异性抗体的疫苗接种策略可以通过阻止病毒进入这些部位来防止HIV的性传播。目前的数据表明，局部免疫途径对于在粘膜中产生这些抗体和抗病毒T辅助（TH）细胞是最佳的。然而，粘膜佐剂增强直肠或阴道接种疫苗的反应尚未在人类中发现。特异性AIM I是确认可在人类直肠和阴道中施用的LT的摄取和确定最大安全剂量，并建立可与LT安全共同施用的HIV p55 gag颗粒的免疫原性剂量。将对妇女组在直肠或阴道中施用1-5马克的小剂量分级LT后的副作用进行评估。为了确认LT摄取，将用ELISA法筛选局部分泌物中的抗LT抗体。然后，较小的妇女群体将使用最大安全LT剂量和250或500马克杯p55进行直肠和阴道免疫，以确认联合制剂也是安全的，并确定在局部分泌物中诱导p55特异性抗体所需的直肠和阴道p55剂量。特异性AIM II是测试LT增强全身和粘膜免疫反应的能力，以及通过直肠或阴道途径共同给药p55的免疫记忆的发展。将比较单独接种p55或p55联合LT的妇女血清、局部和远端分泌物中诱导的抗p55 IgG和IgA抗体水平。诱导TH1/ th2型反应将通过定量测定特异性IgG亚类抗体和p55刺激的外周血单个核细胞体外分泌的细胞因子来评估。记忆细胞的建立将通过使用[3H]胸苷摄取试验测量血液中的淋巴细胞增殖来评估，并通过测量直肠/阴道p55增强后产生的抗体来评估。这项研究将有助于了解粘膜佐剂对诱导局部和远端免疫反应的作用，设计免疫策略，产生对性传播疾病的保护性免疫，以及一种有前途的HIV疫苗亚基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.