concanavalin-a and Tinea

Human peripheral polymorphonuclear neutrophils exhibited potent cytotoxic activity against the dermatophyte fungi Tricophyton quinckeanum and T. rubrum as assessed by inhibition of fungal replication in Sabouraud's agar. Monocytes also showed cytotoxic activity, but this was less pronounced than that of neutrophils, while lymphocytes had no toxic effect. Cytotoxicity showed a linear relationship to the target cell:effector cell ratio, with significant killing detected at a ratio of one neutrophil to one fungal cell. Fungal killing was optimal at incubation times of 2-24 hr for T. rubrum and 2-48 hr for T. quinckeanum. Thereafter, neutrophils were unable to prevent fungal replication while remaining viable. cytotoxicity was markedly reduced by sodium azide, an agent that inhibits haem enzymes, and by catalase, but not by heat-inactivated catalase or superoxide dismutase. The fungicidal activity of neutrophils and monocytes was greatly increased by stimulation with phorbol myristate acetate (PMA) or with concanavalin A (Con A) compounds known to stimulate the secretion of lysosomal enzymes and the production of highly reactive oxygen intermediates. The cytotoxic activity of monocytes to T. quinckeanum, but not to T. rubrum, was also increased by Con A treatment. Neutrophil and monocyte phagocytosis of dermatophytes was demonstrated by electron microscopy studies. Disrupted T. quinckeanum and T. rubrum germlings were identified in the cytoplasm of the phagocytic cells, and similarly disruption of hyphae surrounded, but not engulfed, by neutrophils was also observed. These studies suggest that phagocytosis and/or oxidative products of the respiratory burst of neutrophils and monocytes may be implicated in the killing of dermatophytes in vivo.

Topics: Concanavalin A; Cytotoxicity, Immunologic; Humans; Microscopy, Electron; Monocytes; Neutrophils; Oxygen; Tetradecanoylphorbol Acetate; Time Factors; Tinea; Trichophyton

The antigens of Trichophyton rubrum were studied by means of concanavalin A affinity chromatography and immunoelectrophoresis. The lectin was found to bind 8 of the 35 antigens present in a crude T. rubrum extract. This concanavalin A fraction induced antibody formation in rabbits. Moreover, some human anti-T. rubrum antibodies reacted with this fraction, which was also able to induce lymphocyte transformation in vitro in lymphocytes from infected patients. In addition, skin test studies demonstrated its ability to elicit relevant immediate- and delayed-type hypersensitivity reactions. Thus the antigens of the concanavalin A fraction elicit both IgE and precipitating antibodies and cell-mediated immunity.

Topics: Animals; Antibodies, Fungal; Antigens, Fungal; Chromatography, Affinity; Concanavalin A; Cross Reactions; Glycopeptides; Humans; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Immunoelectrophoresis; Immunoelectrophoresis, Two-Dimensional; Immunoglobulin E; Lymphocyte Activation; Rabbits; Tinea; Trichophyton