Mice immunization with radioattenuated yeast cells of Paracoccidiodes brasiliensis: influence of the number of immunizations.
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.
do Nascimento Martins
Estefânia Mara
EM
Laboratório de Radiobiologia, Centro de Desenvolvimento da Tecnologia Nuclear, Caixa postal 941, Belo Horizonte, MG, CEP 30123-970, Brazil. estefaniabio@yahoo.com.br
Reis
Bernardo Sgarbi
BS
de Resende
Maria Aparecida
MA
de Andrade
Antero Silva Ribeiro
AS
Goes
Alfredo Miranda
AM
D000825:Animal Structures / Q000382:microbiology; D000818:Animals; D000908:Antibodies, Fungal / Q000097:blood; D015169:Colony Count, Microbial; D016207:Cytokines / Q000378:metabolism; D005657:Fungal Vaccines / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010228:Paracoccidioides / Q000276:immunology* / Q000528:radiation effects; D010229:Paracoccidioidomycosis / Q000276:immunology / Q000517:prevention & control*; D014613:Vaccines, Attenuated / Q000276:immunology
D000908:Antibodies, Fungal; D016207:Cytokines; D005657:Fungal Vaccines; D007074:Immunoglobulin G; D014613:Vaccines, Attenuated