Protective immunity induced in mice by F0 and FII antigens purified from Paracoccidioides brasiliensis

Abstract

Paracoccidioides brasiliensis causes a chronic granulomatous mycosis prevalent in South America, and cell-mediated immunity represents the principal mode of protection against this fungal infection. We investigated whether immunization with P. brasiliensis antigens fractionated by anionic chromatography on fast protein liquid chromatography (FPLC) could elicit protective immunity . BALB/c mice were immunized by subcutaneous injection of either 10 μg fractions 0 (F0), II (FII) or III (FIII) in the presence of 100 μg of Corynebacterium parvum and 1 mg of Al(OH) 3 and challenged with pathogenic P. brasiliensis strain. Mice immunized with F0 presented cellular and humoral immune responses with significant production of IFN-γ, and high levels of IgG2a and IgG3 isotypes. Immunization with FII induced significant production of IFN-γ and IL-10 associated with high levels of IgG1 and IgG2a. It was demonstrated that immunization with F0 or FII promoted significant decrease of organ colony-forming units (CFUs) in the lung after challenge infection without fungi dissemination to the spleen or liver. In contrast, FIII immunized mice develop a progressive disseminated disease to spleen and liver presented significant levels of INF-γ, IL-10 or TGF-β associated with high production of IgG1 and IgG2a with low production of IgG2b and IgG3 after challenge infection. Taken together, these findings suggest that antigens of F0 and FII are reliable vaccine candidates against the paracoccidioidomycosis.