Evaluation of the Therapeutic Effect of Radioattenuated Yeast Cells in Experimental Paracoccidioidomycosis

Estefania Mara do Nascimento Martins, Viviane Cristina Fernandes, Elis Araújo Morais, Jankerle N. Boeloni, Maria Aparecida de Resende, Alfredo Miranda Goes and Antero Silva Ribeiro de Andrade

Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis (PCM), the most prevalent deep mycosis in Latin America. The treatment varies according to the chemotherapeutic drug and the disease severity, and the lack of it can results in high frequency of relapse and sequels. Thus, the search for new therapeutic alternatives is necessary. The aim of this study was to evaluate the therapeutic effect of P. brasiliensis yeast cells attenuated by gamma irradiation (LevRad) in Balb/c mice. Mice immunized with LevRad and/or treated with fluconazole presented a significant decrease in the CFU recovery from the lung, liver and spleen in comparison with non-immunized and non-treated infected mice (60 and 120 days after infection). After 120 days from fungal inoculation, no fungi colonies were obtained from the organs of treated and immunized mice. The tissue structure of these organs was largely preserved. At the same time, anti-Mexo specific IgG antibodies levels and TGF-β, IFN-γ, iNOS transcript levels were high and a decrease on the IL-4, IL-10 and TNF-α transcript levels was also verified. An additive protective effect of immunization with LevRad associated to chemotherapy in a PCM experimental model was verified, providing evidence of the therapeutic effect of attenuated yeast for fungal infections.