Effect of acute versus chronic Trichinella pseudospiralis infections on systemic cell-mediated immunity.

Infection of the mouse with Trichinella pseudospiralis is accompanied by pronounced suppression of host inflammatory response. This study examines the effects of infection with this parasite on several key elements in cell-mediated immunity. Early down-regulation of host granulomatous response to subcutaneously implanted cotton string and delayed-type hypersensitivity (DTH) response to trinitrochlorobenzene (TNCB) was followed later during infection by normalization of these parameters compared to that seen in uninfected mice. Cytotoxic T lymphocyte responses to tumor-specific antigens expressed on the syngeneic P91 mastocytoma were depressed early following infection with T. pseudospiralis relative to that seen in uninfected mice but were similar in these two groups during the later stages of infection. Down-regulation of the components of cell-mediated reaction examined herein accompanied the presence of migratory larvae in the host.