Accession Number : ADA192223

Title :   An Investigation of the Memory Response of the Local Immune System to Shigella Antigens.

Descriptive Note : Annual rept. 1 Dec 86-15 Jun 87,

Corporate Author : MICHIGAN UNIV ANN ARBOR

Personal Author(s) : Keren, David F

PDF Url : ADA192223

Report Date : 01 Dec 1987

Pagination or Media Count : 22

Abstract : When the mucosal system is appropriately stimulated, the secretory immunoglobulin A response which results can protect the intestine from damage by microorganisms or their toxic products. Our laboratory has found that oral immunization with virulent or avirulent Shigella flexneri can elicit a significant memory mucosal IgA response. In the present studies, we determine the mechanism of initiation of that immune response. We have found that both invasive and noninvasive S. flexneri are taken up by these specialized surface epithelial cells, M cells, and are packaged into vesicles. This explains why both virulent and avirulent S. flexneri are able to stimulate the mucosal immune response. However, we have also found that the virulent M4243 strain is able to replicate within the follicle-associated epithelium and produces ulceration initially in these sites. Therefore, the M cells serve as a double-edged sword. They ingest antigen including live microorganisms from the gut lumen to process this antigen for a secretory IgA response. However, when pathogenic strains which can break out of the vesicles and replicate are ingested, a focal ulceration results with damage to the intestine. To determine the stimulation of specific lymphocytes within the gut-associated lymphoid tissues following uptake of the antigen, we have begun development of an in vitro model system to follow the course of stimulation for S. flexneri antigens.

Descriptors :   *ANTIGENS, *IMMUNITY, *IMMUNOGLOBULINS, *INTESTINES, *SHIGELLA FLEXNERI, CELLS(BIOLOGY), DAMAGE, EPITHELIUM, IMMUNIZATION, IN VITRO ANALYSIS, LYMPHOCYTES, MICROORGANISMS, MODELS, MUCOUS MEMBRANES, ORAL INTAKE, PATHOGENIC MICROORGANISMS, RESPONSE(BIOLOGY), SECRETION, SHIGELLA, STIMULATION(GENERAL), STRAINS(BIOLOGY), SURFACES, TOXICITY, ULCERS, VIRULENCE

Subject Categories : Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE