IGG SUBCLASS RESPONSE TO A ACTINOMYCETEMCOMITANS

局部青少年牙周炎（LJP）受试者定植的 革兰氏阴性球杆菌伴放线杆菌 经常表现出明显升高的血清IgG抗体滴度， 有机体 最近的研究表明， LJP受试者包括产生特异性IgG抗体 外膜蛋白质和脂多糖存在于 这种生物的外膜。 然而， 抗体应答A.伴放线菌表面抗原， 不完全理解。 多年来，人们认识到， 人血清IgG由四个不同的亚类组成。 这四 亚类不仅在它们的生物学特性（特别是 关于补体激活和与吞噬细胞Fc的结合 受体），但在抗原的性质，诱导其 生产 仅激活的IgG亚类（IgG1和IgG3） 与吞噬细胞上的Fc受体互补并相互作用， 以促进细菌调理作用和吞噬细胞杀伤。 总的来说， 蛋白质抗原优先诱导IgG 1，而多糖 抗原主要诱导IgG 2。 主要的IgG亚类反应是 细菌感染可显著影响IgG的贡献 来主持防守 我们不知道有任何公开的报告描述了 LJP患者对蛋白质和多糖的IgG亚类反应 A. A.伴放线菌 主 这项建议的目标是： 1.确定LJP受试者对分离的IgG亚类应答 A.伴放线菌，包括外膜 蛋白质和脂多糖。 2.定义已知存在于 一些LJP受试者的血清。 3.鉴定调理素IgG识别的外膜成分 抗A.伴放线菌 从拟议研究中获得的信息将提供重要的 深入了解IgG抗体的性质和生物学后果 局限性青少年牙周炎受试者对A. 伴放线菌

Localized juvenile periodontitis (LJP) subjects colonized by the gram-negative coccobacillus Actinobacillus actinomycetemcomitans frequently exhibit markedly elevated serum IgG antibody titers to this organism. Recent studies have demonstrated that the humoral response of LJP subjects includes production of specific IgG antibodies directed toward outer membrane proteins and lipopolysaccharide present in the outer membrane of this organism. However, the significance of the antibody response to A. actinomycetemcomitans surface antigens is incompletely understood. It has been appreciated for some years that human serum IgG consists of four distinct subclasses. These four subclasses differ not only in their biologic properties (particularly with respect to complement activation and binding to phagocyte Fc receptors), but in the nature of the antigens which induce their production. Only IgG subclasses (IgG1 and IgG3) which activate complement and interact well with Fc receptors on phagocytic cells tend to promote bacterial opsonization and phagocytic killing. In general, protein antigens preferentially induce IgG1, whereas polysaccharide antigens induce mainly IgG2. The predominant IgG subclass response to bacterial infection can significantly influence the contribution of IgG to host defense. We are unaware of any published reports describing the IgG subclass response of LJP subjects to protein and polysaccharide antigens on the surface of A. actinomycetemcomitans. The primary objectives of this proposal are to: 1. Determine the IgG subclass response of LJP subjects to isolated surface antigens of A. actinomycetemcomitans, including outer membrane proteins and lipopolysaccharide. 2. Define the subclass of opsonic IgG antibody known to be present in sera of some LJP subjects. 3. Identify the outer membrane constituent recognized by opsonic IgG antibody against A. actinomycetemcomitans. The information derived from the proposed studies will provide important insight into the nature and biological consequences of the IgG antibody response of localized juvenile periodontitis subjects to A. actinomycetemcomitans.