Lymphocyte-mediated cellular immunity in histoplasmosis.

Mononuclear phagocytes freshly harvested from immunized animals restrict the intracellular growth of Histoplasma capsulatum, whereas the same cells maintained in culture for 48 hr do not. Experiments established that within the mixed cell population of the mouse peritoneal cavity the lymphocyte was the most likely mediator of the intracellular growth restriction observed. Partially purified lymphocytes, from the peritoneal cavity of mice immunized by sublethal infection, mediated the suppression of intracellular growth of the fungus in normal mouse macrophages in cell culture.