Analysis of antigenic proteins from Paracoccidioides brasiliensis (Pb) and partial characterization of anti-Pb monoclonal antibodies.

SERRADELL, M.A.; DOCENA, G.H.; GALIZIA, F.; NEGRONI, R.; FOSSATI, C.A.

Punta del Este, Uruguay

Congreso; V° Congreso Latinoamericano de Inmunología; 1999

Asociación Latinoamericana de Inmunología (ALAI)

The sytemic mycosis paracoccidioidomycosis (PCM) is an endemic infectious disease of tropical and subtropical regions of Latin America. It is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). The disorder varies fron an acute to a chronic and disseminated clinical from. The definitive diagnosis of PCM is based on the detection of the typical yeast cell in biological samples. Alternatives ways of diagnosis are based on the detection of specific antibodies by serological methods. The aim of this work was to analyse the immunochemical reactivity of an extract of yeast cells of Pb (strain Utero) employing sera from patients with chronic and disseminated PCM and hyperimmune antisera. Besides, characterisation of several monoclonal antibodies (Mabs) was laso assessed. Protein components of the extract were quantified by Lowry´s and analysed by SDS-PAGE. Specific antibodies from human, rabbit and mouse sera were detected by ELISA and immunoblotting (IB). Either the hyperimmune antisera or the human sera recognized proteins within 12-55 kDa range of molecular weight. Non a characteristic reactivity profile was observed among patients. Cross reactivity between Pb and Histoplasma capsulatum (Hc) was also observed by ELISA and IB employing two rabbit specific antisera. Monoclonal antibody 2C3could recognize a 43 kDa-component, while Mabs 2A8, 3F11 and 5F10 were reactive only by ELISA and dot-blot. On hte other hand, Mab 2C3 could not detect any component from a Hc protein extract. This Mab could be employed for differential serologic diagnosis between Paracoccidioides brasiliensis and Histoplasma capsulatum infections.