A comparative study of the immunoantigenicity of eight Paracoccidioides brasiliensis isolates

Abstract

The present study was carried out to investigate differences in the immunoantigenicity of 8 P. brasiliensis isolates from 3 endemic areas (Botucatu: Pb 1, 2 and 3; São Paulo: Pb 18, 192 and 265; Venezuela: Pb 9 and 73). The antigenic reactivity of each isolate in the indirect fluorescent test (II) and in the immunodiffusion test (ID) was studied using a panel of 20 positive control sera for paracoccidioidomycosis. The humoral (measured by immunodiffusion) and the cellular (measured by the footpad test) immune response inducing capacity of each isolate was assessed by the immunization of mice. It was observed: 1. Pb 265 and Pb 9 showed the highest reactivity in II; 2. Pb 192 and Pb 73 were the most reactive in ID; 3. These results demonstrate differences in antigenicity among these isolates; 4. Pb 18 exhibited weak cellular immune response inducing power and great capacity of evoking antiP. brasiliensis antibody production in the immunized mice showing dissociation of its immunogenicity. These differences may indicate the occurrence of strains of the fungus or may reflect modification of the parasite in the host or during culturing.