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EFFECT OF IGA1 PROTEASE ON SECRETORY IGA ANTIBODY

IGA1 蛋白酶对分泌型 IGA 抗体的影响

基本信息

批准号：
3425167
负责人：
MICHAEL F. COLE
金额：
$ 2.39万
依托单位：
GEORGETOWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-06-01 至 1988-05-31
项目状态：
已结题

项目摘要

The goal of this proposal is to determine the effect of IgA1 protease on secretory IgA antibody activity. Secretory IgA (SIgA) is the principal immunoglobulin isotype in the mucosal secretions of the body. SIgA is thought to play a major role in host defense at mucosal surfaces by inhibiting the colonization of potentially pathogenic microorganisms. A number of mucosal pathogens produce a protease that specifically cleaves the IgA1 subclass at the hinge region to produce Fab and Fc fragments. Despite the potential importance of IgA1 protease as a microbial virulence factor in host-parasite interactions at mucosal surfaces virtually nothing is known concerning the effect of cleavage on the antibody function of SIgA. Comparisons of antibody activity before and after cleavage with IgA1 protease cannot be readily achieved because (1) it is difficult to obtain high titer specific naturally occurring SIgA antibody from normal human serum or secretions and (2) IgA1 proteases synthesized by human mucosal pathogens have extraordinary specificity for only human, gorilla and chimpanzee IgA and will not cleave IgA from other animal species. The chimpanzee has been selected in the current proposal because (1) the chimpanzee can be immunized to induce high levels of specific SIgA antibody in breast milk and, (2) chimpanzee IgA is susceptible to cleavage by IgA1 proteases derived from human mucosal pathogens. The objective of this proposal is to determine whether IgA1 protease can interfere with the functional activity of SIgA antibody in the oral cavity. Accordingly, it is proposed to (1) determine the effect of IgA1 protease on the ability of SIgA antibody to bind to the cariogen, Streptococcus mutans. This will be accomplished by comparing the binding of anti-S. mutans SIgA antibody before and after treatment with IgA1 protease in an enzyme-linked immunosorbent assay. The effect of protease on SIgA antibody, before and after binding to S. mutans will be examined (2) determine the effect of IgA1 protease and the ability of SIgA antibody to agglutinate S. mutans. This will be accomplished by use of an agglutination assay in which the endpoint titer of the SIgA antibody will be compard before and after protease treatment and (3) determine the effect of IgA1 protease on the adherence inhibiting activity of SIgA antibody. This will be accomplished by comparing the effect of protease on the adherence of S. mutans to hydroxyapatite (HA) in the presence of SIgA antibody bound to bacteria or HA.

本提案的目的是确定IgA 1的作用蛋白酶对分泌型伊加抗体活性的影响。分泌型伊加（SIgA）是免疫球蛋白的主要同种型，身体的粘膜分泌物。 SIgA被认为是一种在粘膜表面的宿主防御中起主要作用，潜在致病微生物的定植。一些产生一种蛋白酶，在铰链区的IgA 1亚类产生Fab和Fc 片段尽管IgA 1蛋白酶具有潜在的重要性，宿主-寄生虫相互作用中的微生物毒力因子. 粘膜表面几乎没有什么是已知的影响，对SIgA抗体功能的影响。在用H2 O2切割之前和之后的抗体活性的比较 IgA 1蛋白酶不能容易地获得，因为（1）它很难获得高滴度特异性天然存在的SIgA抗体来自正常人血清或分泌物和（2）IgA 1蛋白酶由人类粘膜病原体合成的具有非凡的仅对人类、大猩猩和黑猩猩伊加和意志特异性不能从其他动物物种中裂解伊加。黑猩猩已经在目前的提案中被选中，因为（1）黑猩猩可以免疫诱导高水平的特异性SIgA抗体在母乳中，（2）黑猩猩伊加容易分裂来源于人类粘膜病原体的IgA 1蛋白酶。的该建议的目的是确定IgA 1蛋白酶是否可以干扰SIgA抗体在细胞中的功能活性，口腔因此，建议（1）确定 IgA 1蛋白酶对SIgA抗体结合致龋剂变形链球菌这将通过比较抗S.变形链球菌SIgA抗体之前和在酶联反应中用IgA 1蛋白酶处理后免疫吸附测定蛋白酶对SIgA抗体的影响，在与S结合之前和之后。将检查变形菌（2）测定IgA 1蛋白酶的作用和SIgA的能力凝集S.变异体这将通过使用凝集试验，其中，将比较蛋白酶前后SIgA抗体处理和（3）确定IgA 1蛋白酶对 SIgA抗体的粘附抑制活性。这将是通过比较蛋白酶对 S.变形菌转化为羟基磷灰石（HA）， SIgA抗体结合细菌或HA。