Candida albicans-specific Ly-2+ lymphocytes with cytolytic activity.

To determine whether antigen (Ag)-specific cytotoxic T lymphocytes are generated during experimental Candida albicans infection, purified L3T4+ and Ly-2+ lymphocytes from immunized mice were cultured in the presence of syngeneic accessory cells, C. albicans Ag, and interleukin 2. Yeast-infected bone marrow macrophages were used as target cells in a standard 51Cr-release assay. Freshly isolated L3T4+ and Ly-2+ lymphocytes failed to lyse either target cell type. However, Ag-specific, major histocompatibility complex (MHC)-unrestricted lysis of infected macrophages was evident with immune Ly-2+ cells after 7-10 days in culture. The cultured cells were greater than 98% Thy-1+, CD3+, L3T4-, Ly-2+, T cell receptor alpha/beta + T cells, and their lytic activity was potentiated by the addition of anti-CD3 monoclonal antibodies. At limiting effector cell numbers, Ag-specific MHC-restricted lymphocytes with cytotoxic activity against infected macrophages could be identified. We suggest that C. albicans infection stimulates multiple cytotoxic cell precursors with varying recognition stringency, which include MHC class I-restricted, Ag-specific cytotoxic T lymphocytes.