Cell-mediated immune responses (CMIR) to Rhinosporidium seeberi in mice

There is no published data on Cell Mediated Immune Responses in experimenta l animals to Rhinosporidium seeberi the causative agent of human and animal rhinosporidiosis. The quantitative mouse foot-pad model was used to assay the Delayed-Type Hypersensitivity (DTH) cell-mediated immune response to ex tracts of purified endospores and sporangia of R. seeberi. Histological exa mination was used to confirm that the foot-pad reactions were compatible wi th DTH reactions in the mouse. We report that sonically disintegrated rhino sporidial endospores/sporangia induced DTH responses in the foot-pads of se nsitized mice which were comparable in intensity and histological profile t o that induced by sheep red blood cells in SRBC sensitized mice. Anti-rhino sporidial antibody was also induced. Filtrates of the soluble antigens in s onicated suspensions failed to evoke a DTH-foot-pad (DTH-FP) response in se nsitized mice although an anti-rhinosporidial antibody response to this pre paration was detected. Prolonged pre-treatment with sonicated suspensions o f endospores and sporangia resulted in a decrease of DTH reactivity as comp ared with reactions following pre-treatment of a shorter duration.