Immunological responses of the toad, Xenopus laevis, to the antigens of the ciliate, Tetrahymena pyriformis

Toads, Xenopus laevis, were immunized with the ciliate Tetrahymena pyriformis and their sera examined for specific anti-Tetrahymena precipitating, immobilizing, agglutinating and lytic antibodies 65–75 days later. Precipitating antibodies were detected in whole antiserum by ring and Ouchterlony tests against soluble antigens of Tetrahymena. Immobilizing, agglutinating and lytic antibodies against living ciliates were also detected in whole serum. Antibody activity was localized in the serum fraction corresponding with mammalian γ-globulin after starch block electrophoresis and this was confirmed by immunoelectrophoresis. After fractionation on Sephadex G-200 precipitating antibodies were found to correspond with γG immunoglobulins and non-precipitating antibodies with both γM and γG. These results are comparable with the situation which exists in rabbits immunized against Tetrahymena pyriformis.