An Investigation of the Memory Response of the Local Immune System to Shigella Antigens.
Annual rept. 1 Feb 82-31 Jan 83,
MICHIGAN UNIV ANN ARBOR
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In the present studies, we have used our chronically isolated ileal loop model in rabbits as a probe to study variables involved in eliciting primary and mucosal memory responses to shigella antigens. In our previous studies, we documented that a local IgA memory response to shigella antigens could be elicited by priming rabbits with three oral, weekly doses of 10 to the 10th power live Shigella X16. No such local IgA memory response in intestinal secretions was found when heat-killed shigella were given in the same dosage orally. Last year, we found that the antigen preparation does not need to invade the surface epithelium in order to stimulate local immunity. This was demonstrated by the finding that the noninvasive strain Shigella flexneri 2457-0 was effective in priming for a mucosal memory response. In the present studies, we demonstrate that heat-killed shigella are not effective as a challenge dose and therefore inappropriate to use to test whether a mucosal memory response is present or not. Therefore, the original studies using the 10 to the 10th power dose of orally-administered heat-killed Shigella X16 were repeated this time with a subsequent live challenge dose. Morphologic studies were completed on the capabilities of isolated lymphoid follicles to process enteropathogens for a mucosal immune response. Included are studies of the efficacy of outer membrane protein preparations, and their ability to, solely or incombination with lipopolysaccharide, provide an effective stimulation for mucosal immune responses.
- Medicine and Medical Research