Dissecting The Interplay of GM-CSF and Neutrophils In IgG and IgA Responses

本研究的目的是阐明佐剂GM-CSF增强疫苗诱导的抗SIV IgG和IgA反应的机制。这些研究将利用该联盟提供的独特资源以及Amara和Pulendran团队的互补和综合专业知识，他们评估了新型Env免疫原诱导中和抗体（nab）的效果（项目1和项目2），Ahmed/Silvestri/Crotty团队探索了T细胞对抗体反应的调节（项目3），Cerutti团队研究了先天免疫细胞对B细胞的调节（项目4）。B细胞通过对病毒表面的包膜（Env）刺突产生核糖核酸（nab）来提供对HIV的免疫保护。然而，诱导强大和持续的NAb反应仍然是一个主要障碍，因为Env是诱导NAb的唯一相关抗原，其特征是序列变异、有限的抗原性和缺乏免疫原性。另一个障碍与缺乏能够在系统和粘膜进入部位有效诱导nab的策略有关。Amara小组的初步数据表明，GM-CSF增强了疫苗诱导的siv反应性IgG抗体在全身淋巴器官中产生的频率和频率，并诱导肠道分泌物中siv特异性IgA的释放。这些作用与增强对肠道挑战的保护有关。在本研究中，我们假设GM-CSF动员并激活了具有B细胞辅助功能的脾脏产生il -21的NBH中性粒细胞的独特亚群。我们认为，NBH细胞通过诱导脾脏B细胞（包括边缘区和记忆区B细胞）中的Ig重链类转换、V(D)J基因体高突变和肠道归巢受体，增强了对SIV的全身IgG和肠道IgA反应。提出了三个目标。目的1是阐明GM-CSF诱导脾B细胞中IgG和IgA类转换的机制。目的2是剖析GM-CSF诱导脾IgA类转换B细胞肠归巢的机制。目的3是确定GM-CSF提高疫苗诱导的针对SIV的全身IgG和肠道IgA反应的有效性的机制。

The goal of this proposal is to elucidate the mechanisms by which the adjuvant GM-CSF enhances vaccine induced IgG and IgA responses against SIV. These studies will take advantage ofthe unique resources made available by this consortium and ofthe complementary and integrative expertise ofthe Amara and Pulendran groups, which evaluate novel Env immunogens for the induction of neutralizing Abs (NAbs) (Project 1 and Project 2). the Ahmed/Silvestri/Crotty group, which explores the regulation of Ab responses by T cells (Project 3). and the Cerutti group, which studies the regulation of B cells by innate immune cells (Project 4). B cells provide immune protection against HIV by producing NAbs to envelope (Env) spikes on the surface ofthe virus. However, eliciting robust and sustained NAb responses remains a major obstacle, because Env, the only relevant antigen for NAb induction, is characterized by sequence variation, limited antigenicity and scarce immunogenicity. An additional obstacle relates to the lack of strategies capable of effectively inducing NAbs both systemically and at mucosal sites of entry. Preliminary data from the Amara group show that GM-CSF enhances the avidity and frequency of vaccine-induced SIV-reactive IgG Abs produced in systemic lymphoid organs and elicits release of SIV-specific IgA in intestinal secretions. These effects correlate with increased protection against an intestinal challenge. In this proposal we hypothesize that GM-CSF mobilizes and activates a unique subset of splenic IL-21-producing NBH neutrophils equipped with B cell helper function. We contend that NBH cells enhance systemic IgG and intestinal IgA responses against SIV by inducing Ig heavy chain class switching, V(D)J gene somafic hypermutation and gut-homing receptors in splenic B cells, including marginal zone and memory B cells. Three aims are proposed. Aim 1 is to elucidate the mechanism by which GM-CSF induces IgG and IgA class switching in splenic B cells. Aim 2 is to dissect the mechanism by which GM-CSF induces intestinal homing of splenic IgA class-switched B cells. Aim 3 is to determine the mechanism by which GM-CSF improves the avidity of vaccine-induced systemic IgG and intestinal IgA responses against SIV..