Candida albicans‐specific Ly‐2+ lymphocytes with cytolytic activity

Abstract

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)‐unre‐stricted lysis of infected macrophages was evident with immune Ly‐2⁺ cells after 7–10 days in culture. The cultured cells were > 98% Thy‐1⁺, CD3⁺, L3T4⁻, Ly‐2⁺, T cell receptor α/β⁺ 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.