Human {alpha}{beta} and {gamma}{delta} T cells from unexposed individuals respond to protein antigens of the yeast form of Paracoccidioides brasiliensis

Paracoccidioides brasiliensis, a dimorphic fungus, causes chronicgranuiomatous mycosis in susceptible individuals. Differentreports have shown that cell-mediated immunity is essentialfor protection against systemic mycosis, including paracoccldloidomycosis.We analyzed the reactivity of ß and T cells fromunexposed Caucasian donors to P. brasiliensis yeast form components.Our results indicate: (I) ß and T cells proliferateafter in vitro stimulation with lysates of P. brasiliensis;(II) similar numbers of ß T cells (f = 1/21,000) andof T cells (f = 1/8000) respond to P. braslllensls; (III) P.braslllensls-reactive T cells express the V9V2 TCR; (Iv) thestimulatory activity of P. brasilensis for both ßand T cells primarily resides in a high molecular weight (100kDa) and in a low molecular weight (<<1 kDa) fraction;(v) the ligands responsible for stimulation of both ßand T cells are sensitive to proteinase treatment We concludethat both ß and T cells from healthy individualsrespond to ubiquitous protein antigens of P. brasiliensis.