Optimizing Immunogenicity of Lactobacillus as a Mucosal Vaccine Against HIV-1

描述（由申请人提供）：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。乳酸菌是人类胃肠道中非常常见的共生菌，被商业上用于加工和保存食品，因此它是安全的，不太可能刺激抗媒介免疫反应。此外，由于对功能基因组学的了解，乳酸杆菌易于制造、储存和高度可操作。众所周知的益生菌活性至少部分是由于乳酸菌与树突状细胞的相互作用。乳酸杆菌激活DC并刺激细胞因子的产生，从而导致T细胞的Th1极化。我们已经进行了初步的免疫原性研究，并证明了使用乳酸杆菌作为HIV-1疫苗载体的原理证明，但载体必须进一步优化以提高免疫原性。在这里提出的研究中，我们将研究宿主/载体相互作用，以确定重组乳酸杆菌胃肠道定殖的动力学和位置，以及重组蛋白的表达是否影响本地菌群。将确定HIV-1抗原表达的最佳亚细胞位置，并在小鼠中进行粘膜和全身体液和细胞免疫反应的综合评估。为了进一步提高免疫原性，鞭毛蛋白将被乳酸菌表达，作为一种通过TLR5刺激增加胃肠道先天免疫激活的方法。总之，这些研究将确定乳酸菌是否值得进一步开发作为HIV-1口服疫苗载体。公共卫生相关性：这些研究的目的是利用乳酸菌开发一种新的HIV疫苗策略。使用乳酸菌的疫苗是安全的，制造成本低廉，并且可以口服。如果成功，这一战略可能对艾滋病毒预防产生重大影响。

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. Lactobacillus is a very common commensal of the human gastrointestinal tract and is used commercially to process and preserve food, thus it is safe and unlikely to stimulate anti-vector immune responses. Futhermore, Lactobacillus is easy to manufacture, store and is highly manipulatable as the functional genomics are well understood. The well-known probiotic activities are due at least in part to the interaction of Lactobacillus with dendritic cells. Lactobacillus activates DC and stimulates cytokine production that leads to Th1 polarization of T cells. We have performed preliminary immunogenicity studies and demonstrated proof-of-principle for the use of Lactobacillus as a vaccine vector against HIV-1 but the vector must be further optimized to increase immunogenicity. In the studies proposed here, we will investigate the host/vector interaction to determine the kinetics and location of gastrointestinal colonization by recombinant Lactobacillus and whether recombinant protein expression affects the indigenous flora. The optimal subcellular location for HIV-1 antigen expression will be determined and a comprehensive assessment of mucosal and systemic humoral and cellular immune responses will be performed in mice. To further increase immunogenicity, flagellin will be expressed by the Lactobacillus as a method to increase innate immune activation in the gastrointestinal tract via TLR5 stimulation. Together these studies will determine whether Lactobacillus is worth further development as an oral vaccine vector against HIV-1. PUBLIC HEALTH RELEVANCE: The purpose of these studies is to develop a novel HIV vaccine strategy using Lactobacillus. A vaccine using lactobacilli would be safe, inexpensive to manufacture, and could be delivered orally. If successful, this strategy could have a significant impact on HIV prevention.