High Mannose Type Carbohydrate-based HIV/AIDS Vaccine

描述（由申请人提供）：虽然体液免疫是控制HIV-1猖獗传播的有效HIV/AIDS疫苗的关键组成部分，但目前在临床前和临床试验中的候选疫苗似乎很少能引起广泛中和抗体。多项证据表明，HIV-1糖蛋白gp120上的高甘露糖型碳水化合物是开发广泛中和抗体的新靶点。首先，gp120上的高甘露糖聚糖通过与免疫细胞（包括树突状细胞）相互作用在HIV传播和感染中发挥关键作用。其次，其中一种广泛中和的HIV单克隆抗体2G12可以识别gp120上的高甘露糖型聚糖的构象表位。第三，一种有效的HIV抑制剂Cyanovirin-N与高甘露糖聚糖末端a1,2链甘露糖残基结合。最后，gp120上的碳水化合物在不同的HIV-1亚型和毒株中被很好地暴露和保守。为了靶向gp120上的高甘露糖聚糖，我们创建了酿酒酵母的n -糖基化突变体，鉴定了几种与2G12交叉反应的酵母糖蛋白，诱导了与HIV-1和SIV的Env糖蛋白交叉反应的免疫血清，并中和了HIV-1假病毒。这些血清的gp120结合和中和假病毒的活性广泛，但免疫血清的抗体滴度和中和效力有待提高。

DESCRIPTION (provided by applicant): Although humoral immunity is a critical component in an effective HIV/AIDS vaccine to control the rampant spread of HIV-1, few of the vaccine candidates currently in preclinical and clinical trials appear to elicit broadly neutralizing antibodies. Several lines of evidences show that high mannose type carbohydrates on the HIV-1 glycoprotein gp120 are a novel and promising target to develop broadly neutralizing antibodies. First, high mannose glycans on gp120 play a critical role in HIV transmission and infection through interaction with immune cells, including dendritic cells. Second, one of the few broadly neutralizing HIV monoclonal antibodies, 2G12, recognizes a conformational epitope of high mannose type glycans on gp120. Third, a potent inhibitor of HIV, Cyanovirin-N, binds to terminal a1,2-linked mannose residues on high mannose glycans. Last, the carbohydrates on gp120 are well exposed and conserved among different HIV-1 subtypes and strains. To target the high mannose glycans on gp120, we have created N-glycosylation mutants of S. cerevisiae, identified several yeast glycoproteins that cross-react with 2G12, elicited immune sera that cross-react with Env glycoproteins of HIV-1 and SIV, and neutralized HIV-1 pseudoviruses. The gp120 binding and pseudovirus neutralization activities of these sera are broad, but the antibody titer and neutralization potency of the immune sera need to be improved. We hypothesize that higher levels of Mana1,2Man-specific antibodies with stronger gp120 binding and neutralizing activities can be induced in some of the proposed multiple groups of animals immunized with this new vaccine formulation. The Specific Aims are, (1) optimization of immunization procedures with the whole cells from triple mutant yeast of S. cerevisiae to elicit stronger gp120 cross-reactive and neutralizing antibodies; and (2) analyses of antigenicity and immunogenicity of 2G12 cross-reactive yeast glycoproteins, and elicitation of potent and broadly neutralizing antibodies using a prime-boost strategy. If success, this novel formulation of immunogen from yeast mutant strain will be a safe, cheap, and effective HIV/AIDS vaccine against a broad range of HIV-1 primary isolates. PUBLIC HEALTH RELEVANCE: Although humoral immunity is a critical component in an effective HIV/AIDS vaccine to control the rampant spread of HIV-1, few of the vaccine candidates currently in preclinical and clinical trials appear to elicit broadly neutralizing antibodies. Several lines of evidences show that high mannose type carbohydrates on the HIV-1 glycoprotein gp120 are a novel and promising target to develop broadly neutralizing antibodies. First, high mannose glycans on gp120 play a critical role in HIV transmission and infection through interaction with immune cells, including dendritic cells. Second, one of the few broadly neutralizing HIV monoclonal antibodies, 2G12, recognizes a conformational epitope of high mannose type glycans on gp120. Third, a potent inhibitor of HIV, Cyanovirin-N, binds to terminal a1,2-linked mannose residues on high mannose glycans. Last, the carbohydrates on gp120 are well exposed and conserved among different HIV-1 subtypes and strains. To target the high mannose glycans on gp120, we have created N-glycosylation mutants of S. cerevisiae, identified several yeast glycoproteins that cross-react with 2G12, elicited immune sera that cross-react with Env glycoproteins of HIV-1 and SIV, and neutralized HIV-1 pseudoviruses. The gp120 binding and pseudovirus neutralization activities of these sera are broad, but the antibody titer and neutralization potency of the immune sera need to be improved. We hypothesize that higher levels of Mana 1,2Man-specific antibodies with stronger gp120 binding and neutralizing activities can be induced in some of the proposed multiple groups of animals immunized with this new vaccine formulation. The Specific Aims are, (1) optimization of immunization procedures with the whole cells from triple mutant yeast of S. cerevisiae to elicit stronger gp120 cross-reactive and neutralizing antibodies; and (2) analyses of antigenicity and immunogenicity of 2G12 cross-reactive yeast glycoproteins, and elicitation of potent and broadly neutralizing antibodies using a prime-boost strategy. If success, this novel formulation of immunogen from yeast mutant strain will be a safe, cheap, and effective HIV/AIDS vaccine against a broad range of HIV-1 primary isolates.