Protective anti-LPS antibodies: what are they?

描述（由申请方提供）：基于霍乱弧菌LPS（脂多糖）的霍乱疫苗的开发是通过杀弧菌抗LPS应答与免疫力的相关性来证明的。两种O 1（血清群）LPS血清型，稻叶和小川与地方性和大流行性霍乱有关。两种LPS血清型在感染或接种后诱导保护性抗体。在结构上，血清型是相同的，除了末端糖（perosamine），它在Ogawa的2位有一个甲氧基，但在Inaba有一个羟基。Ogawa LPS的末端糖是保护性B细胞表位。合成的小川型霍乱弧菌的Perosamine六糖与BSA偶联（CHO-BSA）诱导保护性抗体。我们推测稻叶LPS的末端糖也可以诱导保护性抗体。稻叶新糖缀合物确实诱导抗体，但令人惊讶的是，它们没有保护性。相反，用纯化的天然稻叶LPS免疫诱导高度保护性抗体。初步数据表明，由Inaba CHO-BSA缀合物诱导的Inaba抗体具有足够的亲和力以在ELISA中评分，但不足以在体内具有保护性。用天然LPS引发，然后提供Inaba CHO-BSA，在10天内产生高ELISA滴度和保护性抗体。我们假设稻叶LPS和稻叶CHO-BSA选择不同的B细胞，并且稻叶CHO-BSA可以与稻叶LPS选择的B细胞交叉反应以扩增它们，因此可以为生活在具有记忆B细胞但体液免疫减弱的流行区的那些人提供有效的疫苗免疫原。将生成针对两种Inaba免疫原的单克隆抗体（mAb），以确定免疫期间是否选择了不同的B细胞。R21补助金非常适合这些需要开发试剂以解决霍乱生物学基本问题的研究。一种新的技术，表面等离子体共振（SPR）将用于表征的单克隆抗体的亲和力。这些实验是有风险的，因为它们需要产生多种试剂来完成抗LPS抗体的群体分析。这项研究是高回报，因为试剂，无论确切的特异性，将产生将映射的抗体库稻叶LPS的末端糖。我们将阐明具有保护性的抗霍乱弧菌LPS抗体的“类型”，从而证实是否使用稻叶新缀合物作为疫苗组分。

DESCRIPTION (provided by applicant): Development of a V. cholerae LPS (lipopolysaccharide)- based cholera vaccine is justified by the correlation of vibriocidal anti-LPS responses with immunity. Two O1 (serogroup) LPS serotypes, Inaba and Ogawa are associated with endemic and pandemic cholera. Both LPS serotypes induce protective antibody following infection or vaccination. Structurally, the serotypes are identical except for the terminal sugar (perosamine) which has a methoxyl group at position 2 in Ogawa, but a hydroxyl group in Inaba. The terminal sugar of the Ogawa LPS is a protective B cell epitope. Synthetic perosamine hexasaccharides of V. cholerae, serotype Ogawa coupled to BSA (CHO-BSA) induced protective antibody. We hypothesized that the terminal sugar of Inaba LPS would also induce protective antibody. Inaba neoglycoconjugates did induce antibodies but surprisingly they were not protective. In contrast, immunization with purified native Inaba LPS induced highly protective antibody. Preliminary data indicate that Inaba antibodies induced by the Inaba CHO-BSA conjugates have sufficient affinity to score in an ELISA but not enough to be protective in vivo. Priming with native LPS and then providing the Inaba CHO-BSA resulted in high ELISA titers in 10 days and antibodies that are protective. We hypothesize that Inaba LPS and Inaba CHO-BSA select different B cells, and that Inaba CHO-BSA can cross react with Inaba LPS-selected B cells to expand them and thus may provide an effective vaccine immunogen for those living in endemic areas with memory B cells but waning humoral immunity. Monoclonal antibodies (mAb) will be generated to the two Inaba immunogens to determine if different B cells are selected during immunization. An R21 grant is well suited for these studies that require reagent development to address a fundamental question in cholera biology. A new technology, surface plasmon resonance (SPR) will be used to characterize the affinity of the mAbs. The experiments are risky as they require generation of multiple reagents to complete the population analysis of anti-LPS antibodies. The study is high pay off because reagents, regardless of the exact specificity, will be generated that will map the antibody repertoire for Inaba LPS's terminal sugar. We will clarify the "type" of anti-V. cholerae LPS antibodies that are protective and thus substantiate or not the use of Inaba neoconjugates as a vaccine component.