Characterization and cloning of Schistosoma mansoni immunogens recognized by protective antibodies.

In this report we have shown that mice vaccinated twice with radiation-attenuated cercariae elicit a much enhanced or unique response against six adult worm glycoproteins with molecular sizes of 200, 160, 140, 94, 58-56, and 43 kDa. In the case of the schistosomulum, vaccinated mice showed an enhanced or unique response to antigens of 200, 58, 46, 43, 25, and several glycoproteins in the range 65 to 50 kDa. That some or all of these antigens may be important for immunoprophylaxis against schistosomiasis is supported by the observations that 1. polyclonal antiserum (anti-IrV) prepared against these antigens also reacts with the major schistosomular surface antigens, and 2. this antiserum reacts with epitopes exposed on the surface of both newly transformed schistosomula and lung-stage schistosomula. In this study we also observed that the majority of the surface-iodinated antigens recognized by the anti-IrV serum were also recognized by sera from both vaccinated and patently infected mice. Simpson et al. (1985) have also shown that sera from vaccinated and infected mice recognized the same schistosomular surface antigens. It is possible, however, that the immune response of vaccinated mice is directed against different carbohydrate or peptide epitopes on these molecules, and that recognition of such epitopes is important for immune protection. Towards this goal we have cloned several schistosoma proteins reactive with the anti-IrV serum to identify peptide epitopes relevant for immunoprotection.