IgA inducing peptide

描述（由申请人提供）：伊加是大多数哺乳动物物种粘膜分泌物中的主要IG同种型，因此理想地定位于防止病原体进入。我们利用大量的粘膜组织，包括淋巴结和派尔集合淋巴结在牛开发一个cDNA文库，以探测调节伊加表达的因子。我们在牛中鉴定了一种新的因子，其影响体外伊加产生，并将该因子命名为伊加诱导蛋白或IGIP。这项为期两年的创新提案的总体目标是将我们对这种新因子的研究扩展到人类，并阐明IGIP影响伊加产生的机制。我们对该项目的工作假设是间质树突状细胞衍生的IGIP在哺乳动物物种中是保守的，并且是诱导IgA表达细胞的T依赖性和独立途径的重要组成部分。我们还假设树突状细胞和/或B细胞中IGIP调节的改变是选择性伊加缺乏的一个因素。本研究的具体目的是：1）建立体外模型，确定IGIP在表达IgA的人B细胞分化中的作用; 2）鉴定正常人外周血白细胞中IGIP转录本和蛋白的细胞来源，包括树突状细胞、T细胞、B细胞和单核细胞/巨噬细胞; 3）比较选择性伊加缺乏症患者外周血白细胞IGIP转录本、蛋白表达及对IGIP的反应性。拟议的研究将是第一个建立机制，通过该机制，一个独特的，最近发现的因子与已知因子如TGF-β或IL-10协同作用，以促进伊加应答，并应有助于澄清人DC在调节伊加应答中的作用。此外，拟定的研究将开始检查确定IGIP与伊加产生的临床异常之间的潜在关系。

DESCRIPTION (provided by applicant): IgA is the predominant Ig isotype in mucosal secretions of most mammalian species and is thus ideally localized to prevent pathogen entry. We took advantage of the large quantities of mucosal tissues, including lymph nodes and Peyer's patches in cattle to develop a cDNA library to probe for factors that regulate IgA expression. We identified a novel factor in the bovine, which impacts IgA production in vito and designated the factor, IgA Inducing Protein or IGIP. The general goal of this two-year innovative proposal is to extend our studies of this novel factor to humans and to elucidate the mechanisms by which IGIP influences IgA production. Our working hypothesis for the project is that interstitial dendritic cell derived- IGIP is conserved across mammalian species and is an essential component of T-dependent and independent pathways for induction of IgA-expressing cells. We also hypothesize that altered IGIP regulation in dendritic cells and/or B cells is a factor in selective IgA deficiency. The specific aims that will test this hypothesis are: 1) Use an established in vitro model to determine the role of IGIP in differentiation of IgA-expressing human B cells; 2) Identify the cellular sources of IGIP transcripts and protein in peripheral blood leukocytes including dendritic cells, T cells, B cells and monocyte/macrophages from normal individuals; 3) Compare the expression of IGIP transcripts and protein and the responsiveness to IGIP of peripheral blood leukocytes from patients with selective IgA deficiency. The proposed studies will be the first to establish the mechanism(s) by which a unique, recently identified factor acts in concert with known factors such as TGF-beta or IL-10 to promote IgA responses and should help clarify the role of human DC in the regulation of the IgA responses. In addition, the proposed studies will begin to examine determine the potential relationship between IGIP and clinical abnormality in IgA production.