Recombinant Lactobacillus as an Oral Mucosal Vaccine Against HIV-1

描述(申请人提供)：HIV-1的传播主要发生在粘膜表面，因此成功的HIV-1疫苗必须诱导粘膜、体液和细胞免疫反应。几个世纪以来，乳酸菌一直被用来加工和保存食物，并以其益生菌活性而闻名。最近，乳酸菌家族的成员被探索作为疫苗载体。加瑟氏乳杆菌是人类口腔和胃肠道的常见共生菌，作为HIV-1的口服黏膜疫苗载体可能特别有用。加瑟氏乳杆菌定植于口腔，是肠道定植的来源。此外，加瑟氏乳杆菌可激活树突状细胞并刺激细胞因子的产生，从而导致T细胞的Th1极化。在初步研究中，表达HIV-1 Gag的重组加瑟氏乳杆菌在单次口服剂量后，可诱导结肠和生殖道内的血清免疫球蛋白G、粘膜免疫球蛋白A和细胞介导的反应。在这里，我们建议更好地确定口服免疫后加瑟氏乳杆菌的剂量、分布和持久性。然后，我们将通过共表达鞭毛蛋白作为一种手段，通过TLR5刺激先天免疫系统，并确定加色乳杆菌是否能够为Env的真核表达提供DNA疫苗，从而提炼出作为免疫原的加色乳杆菌。调节性T细胞在黏膜免疫中的作用将通过在口服免疫的同时消耗Treg来评估。最后，将进行一项强有力的攻击性研究，以确定加瑟氏乳杆菌是否可以诱导保护性免疫。这些研究将使用HIV-1的CAT/FIV模型进行，因为猫有与人类相似的口咽粘膜相关淋巴组织，可以使用统计相关数字进行经济学研究，并且可以使用细胞相关病毒和无细胞病毒在阴道内挑战致病性FIV。项目简介：HIV-1的传播主要发生在粘膜表面，因此，成功的HIV-1疫苗必须诱导粘膜、体液和细胞免疫反应。加瑟氏乳杆菌是一种常见的益生菌，在人类口腔和胃肠道中发现，因此可能是一种特别有效的艾滋病毒-1疫苗载体。这里提出的研究将探索改造重组加瑟氏乳杆菌的策略，这种重组乳杆菌可以通过口腔粘膜诱导对HIV-1的保护性免疫反应。

DESCRIPTION (provided by applicant): Transmission of HIV-1 occurs predominately at mucosal surfaces and therefore a successful vaccine against HIV-1 must induce mucosal humoral and cellular immune responses. Lactic acid bacteria have been used for centuries to process and preserve food and are well known for their probiotic activities. Recently members of the lactic acid bacteria family have been explored as vaccine vectors. Lactobacillus gasseri is a common commensal of the human oral cavity and gastrointestinal tract and may be particularly useful as an oral mucosal vaccine vector against HIV-1. L. gasseri colonizes the oral cavity and serves as a source for colonization of the intestinal tract. In addition, L. gasseri activates dendritic cells and stimulates cytokine production that leads to Th1 polarization of T cells. In preliminary studies, recombinant L. gasseri expressing HIV-1 Gag induced serum IgG, mucosal IgA and cell mediated responses measured in the colon and reproductive tract after a single oral dose. Here we propose to better determine the dose, distribution and persistence of L. gasseri after oral immunization. We will then refine L. gasseri as an immunogen by co-expressing flagellin as a means to stimulate the innate immune system through TLR5 and determining whether L. gasseri can deliver a DNA vaccine for the eukaryotic expression of Env. The role of regulatory T cells in mucosal immunization will be assessed by depleting Treg concomitant with oral immunization. Finally, a robust challenge study will be performed to determine whether L. gasseri can induce protective immunity. These studies will be performed using the cat/FIV model of HIV-1 since cats have oropharyngeal mucosa associated lymphoid tissue similar to humans, can be economically studied using statistically relevant numbers, and can be vaginally challenged with pathogenic FIV using cell-associated and cell-free virus. Project Narrative: Transmission of HIV-1 occurs predominately at mucosal surfaces and therefore a successful vaccine against HIV-1 must induce mucosal humoral and cellular immune responses. Lactobacillus gasseri is a common probiotic bacterium found in the human oral cavity and gastrointestinal tract and as such may be a particularly effective vaccine vector against HIV-1. Studies proposed here will investigate strategies to engineer recombinant L. gasseri that can induce a protective immune response against HIV-1 via the oral mucosa.