Caracterização imunológica da proteína recombinante gliceraldeído-3-fosfato desidrogenase do patógeno humano Paracoccidioides brasiliensis

Abstract

Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis (PCM), a main medical problem in Latin America. When inhaled, the fungus mycelia propagules differentiate into yeast phase, establishing the infection in human lungs. The disease establishment depends, among several aspects, on the ability of fungus to modulate the host immune system. The Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein has been characterized in laboratory as an immunogenic protein of P. brasiliensis. In previous studies the cDNA, that encodes the P. brasiliensis GAPDH, was subcloned into the expression vector TOPO pET100 to obtain the recombinant fusion protein. This protein was overexpressed in an Escherichia coli host to produce high levels of recombinant protein that was purified by affinity chromatography. In this study, the recombinant protein was evaluated regarding to its immunological reactivity with sera of PCM patients. Therefore, this research aimed to use the recombinant protein in studies of immune reactivity with sera from patients with PCM. For this purpose, a molecular approach was used in this research. The reactivity with purified recombinant GAPDH (rGAPDH) protein of 70 human sera samples were tested by Western blot analysis. Immunoblots indicated that rGAPDH was able to react with antibodies present in all sera of PCM patients, but not with sera of control patients. Thus, rGAPDH may be added to the small arsenal of immunoreactive molecules of P. brasiliensis and tested to its incorporation to disease serodiagnosis test.