The effect of human lymphokine on the growth of Trichophyton mentagrophytes.

Lymphokine was tested for fungal growth inhibitory activity against the filamentous fungus Trichophyton mentagrophytes. Human peripheral blood lymphocytes from a donor exhibiting delayed type cutaneous hypersensitivity to a trichophytin skin test were cultured with trichophytin and PHA-P. Culture supernatants were assayed for lymphokine activity using the lymphotoxin sensitive mouse L-929 alpha fibroblast. Lymphocyte activation to PHA-P and trichophytin was confirmed by monitoring 3H-thymidine incorporation. Supernatants from 2-day PHA-P and 6-day trichophytin activated cultures were found to contain potent lymphokine activity. This activity was not diminished by the addition of ferric iron sufficient to saturate the contained transferrin. Supernatants from unstimulated control cultures contained no lymphokine activity. Undiluted lymphokine containing supernatants and nonlymphokine containing control supernatants were evaluated for fungal growth inhibitory activity using a sensitive radiometric growth assay. Iron supplemented supernatants retaining potent lymphokine activity did not inhibit fungal growth. Non-iron supplemented supernatants and fresh medium containing serum inhibited fungal growth. Our data suggest that lymphokine active against mammalian cells is not directly antagonistic to the growth of the filamentous fungus T. mentagrophytes but does not exclude the possibility that activated lymphocytes release a chelator such as transferrin that can inhibit fungal growth.