THE FEEDING OF A-TYPE RED-BLOOD-CELLS IN-VITRO AND THE ABILITY OF SCHISTOSOMA-MANSONI SCHISTOSOMULES TO ACQUIRE A-EPITOPES ON THEIR SURFACES

In vitro-raised Schistosoma mansoni schistosomules fed human A type re d blood cells at day 7 postpenetration displayed A epitopes on their s urfaces but not B epitopes when tested by the mixed agglutination proc edure, Schistosomules treated with colchicine prior to exposure to red blood cells, exposed to plasma derived from human A type blood, or no t exposed to host red blood cells did not display A epitopes on their surfaces. Under the conditions used in these experiments, it is likely that feeding of host red blood cells may be necessary for the tegumen t to become responsive to adsorption of host red blood cell epitopes.