The Journal of clinical investigation
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Pityrosporum orbiculare, the presumed etiologic agent of tinea versicolor, was cultured in vitro and antigenic extracts prepared from the cultured organisms. Studies with lymphocytes from human cord blood and peripheral blood of guinea pigs demonstrated that such extracts were not mitogenic. Further studies in guinea pigs indicated that the animals could be sensitized by the injection of P. orbiculare extract in Freund's complete adjuvant and that this extract could elicit lymphocyte transformation and delayed skin test responses in sensitized animals. ⋯ This was also true if only subjects with positive lymphocyte transformation responses to these antigens were considered. Leukocyte migration inhibitory factor responses to streptokinase/streptodornase were not significantly different between the two groups. Therefore, it appears that although both normal subjects and tinea versicolor patients demonstrate prior sensitization to antigens of P. orbiculare, the effector function of lymphocytes from most tinea versicolor patients appears to be impaired in that they produce subnormal amounts of the mediator leukocyte migration inhibitory factor when stimulated with antigenic extracts of this organism.