Preliminary analysis of cross reactivity between antigens of Paracoccidioides brasiliensis and Histoplasma capsulatum.

SERRADELL, M.A.; NEGRONI, R.; FOSSATI, C.A.

Buenos Aires, Argentina

Congreso; 14th Congress of the International Society for Human and Animal Mycology; 2000

International Society for Human and Animal Mycology (ISHAM)

Histoplasmosis and paracoccidiodomycosis are systemic mycosis of endemic areas caused by hte dimorphic fungi Histoplasma capsulatum (Hc) and Paracoccidioides brasiliensis (Pb) respectively. These taxonomically related species are distributed on overlapped emdemic areas in our continent. Diagnosis of both diseases is achieved by microscopic observation and culture of the aethiological agent, or indirectly by serological tests. The aim of this work is the analysis and characterization of cross reactivity between antigenic extracts prepared from yeast of both microorganisms by means of specific antisera and/or monoclonal antibodies (Mab) raised in our laboratory. Protein components of these extracts were quantified by Bradford´s method and analyzed by SDS-PAGE. Preprative electrophoresis was optimized for separation of cytosolic components of Pb. Antibodies specificity was assessed through immunoblotting (IB) and ELISA. Cross reactivity was confirmed by IB and inhibition ELISA. It was observed that extracts from both fungi contain antigens ranging from 12 to 100 kDa of molecular mass. Among them several cross reactive prtoenis were detected. Three of hte Mabs obtained (2A8, 3F11 and 5F10) were positive to both Pb and Hc extracts by ELISA. Mab 2C3, although recognized by immunoblotting a component of approximately 63 kDa from the Pb extract but did not show any reactivity against Hc components. Some other hybridomas are currently under analysis.