Detection of specific antibodies to a 63-kDa component of Paracoccidioides brasiliensis in infected patients.

SERRADELL, M.; CACACE, M.L.; NEGRONI, R.; TARANTO, N.; FOSSATI, C.A.

Pirenópolis, Brasil

Congreso; VIII Encontro Internacional sobre Paracoccidioidomicose; 2002

In the last decade a variety of antigens from Paracoccidiodes brasiliensis (PB) have been chracterized and used for the development od different methods fro the seroligcal diagnosis of the infection. These methods are mainly based on the employment of purified or recombinant antigens or specific monoclonal antibodies (Mabs). In our laboratory we have obtained a Mab (PB-2C3) specific to a cytoplasmic component of 63 kDa from PB that does not react with an extract from Histoplasma capsulatum. Our main goal was to analyze the reactivity of sera from patients iwth paracoccidioidomycosis (PCM) or other related and unrelated mycosis to this antigen. To this end weemployed a ELISA with Mab PB-2C3 capturing its specific antigen from a crude extract from PB. We studiedsera from 47 PCM patients (40 with chronic disseminated and 7 with acute PCM), 24 Histoplasma capsulatum infected patients (HP), 3 suffering aspergillosis (ASP) and 3 with candidiasis (Cd). To establish the cut-off value of the ELISA sera from 20 healthy subjects were used. Results sohw that serum from 33/47 PCM patients and 7/24 from HP, were able to recognize the 63 kDa antigen while the rest of sera analyzed were negative. No differential degree of reactivity was observed between chronic and acute PCM subjects. By indirect ELISA with a PB crude extract we observed that 45/47 of PCM, 18/24 of HP and 2/3 ASP patietns were positive. On the basis of these results we rae trying to purify and identify this 63 kDa component that could be better than the total extract from PB in the development of serological methods for the diagnosis of PCM.