ABSTRACT
Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The present chapter describes the methodology to obtain radioattenuated yeast cells of P. brasiliensis and a protocol to evaluate protective response elicited by this immunogen in experimental paracoccidioidomycosis. The radioattenuated yeast provides a valuable tool for immunological studies in experimental paracoccidioidomycosis and vaccine research.
Subject(s)
Fungal Vaccines/immunology , Paracoccidioides/immunology , Paracoccidioides/radiation effects , Paracoccidioidomycosis/immunology , Paracoccidioidomycosis/microbiology , Vaccines, Attenuated/immunology , Animals , Antibodies, Fungal/immunology , Cytokines/blood , Cytokines/metabolism , Enzyme-Linked Immunosorbent Assay , Gamma Rays , Immunization , Immunocompromised Host , Male , Mice , Microbial Viability/radiation effects , Paracoccidioides/pathogenicity , Paracoccidioidomycosis/genetics , Paracoccidioidomycosis/metabolism , VirulenceABSTRACT
Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America. Up to the moment no vaccine has been reported. The aim of this study was to evaluate the influence of the number of immunizations on the protection elicited by radioattenuated yeast cells of P. brasiliensis. BALB/c mice were divided into two groups that were immunized once (Group 1) or twice (Group 2), respectively. In each group, mice were divided into sub-groups that were challenged 30, 45, or 60 days after the second immunization. Organ colony-forming units (CFUs) was determined 90 days post-challenge. A significant reduction in CFUs recovery was verified in both groups, but it was higher in Group 2. Histologic alterations were observed only in Group 1. The cytokines IL-4, IL-10, and IFN-gamma were produced in mice of Group 1. In Group 2, only IFN-gamma was significantly detected. IgG2a predominance relative to IgG1 was also observed in Group 2. Altogether, our results indicated that mice immunized once developed a mixed Th1/Th2 response, which was less efficient in the infection control, while a trend to a Th1 pattern was obtained with two immunizations, promoting optimal elimination of P. brasiliensis yeast cells from mice tissues.
Subject(s)
Fungal Vaccines/immunology , Paracoccidioides/immunology , Paracoccidioidomycosis/prevention & control , Animal Structures/microbiology , Animals , Antibodies, Fungal/blood , Colony Count, Microbial , Cytokines/metabolism , Immunoglobulin G/blood , Male , Mice , Mice, Inbred BALB C , Paracoccidioides/radiation effects , Paracoccidioidomycosis/immunology , Vaccines, Attenuated/immunologyABSTRACT
Paracoccidioides brasiliensis is the fungus agent of paracoccidioidomycosis, a chronic systemic disease prevalent in Latin America. The aim of the present work was to evaluate the protection elicited by the immunization of BALB/c mice with radioattenuated yeast cells of P. brasiliensis. The immunization promoted a long lasting protection against highly infective yeast forms of P. brasiliensis. A 99.5% decrease in CFUs recovery was verified 90 days post challenge. At the same time the levels of IgG2a and IFN-gamma were high while a very low production of IL-10 and IL-5 was verified, suggesting that a Th1 pattern was dominant. This work shows the potential of radioattenuated yeast cells for the development of vaccines against fungi infections.
