Schistosoma Mansoni Shares

The production of mAbs of various isotypes to Schistosoma mansoni has greatly contributed to the appreciation of the function of antibodies in the immunity against schistosomiasis, and has allowed the characterization of several potential protective antigens . Using this approach, we clearly established in previous studies (1, 2) the close relationship existing between a 38,000 Mr S. mansoni schistosomulum surface antigen and the expression of eosinophil-mediated killing of schistosomula . The 38,000 M,. antigen was initially characterized by the IPLSm 1 rat IgG2amAb that exhibits a marked eosinophil-dependent cytotoxicity and passively transfers a high degree of protection towards a cercarial challenge (1, 2) . This particular surface antigen was also shown to react with polyclonal antibodies present in various infected hosts including mice, rats, monkeys, and humans (3) . Additional studies revealed that 97% of a group of 120 Brazilian patients with S. mansoni infection produced circulating antibodies against this antigen, suggesting that the 38,000 Mi molecule corresponds to a potent immunogen in man . More interestingly, the antibody response was demonstrated to appear in young children, to be maximal in older patients, and showed a parallelism with the prevalence and the intensity of the infection. This indicated that the antibody response against the 38,000 Mr antigen could be considered an important marker of S. mansoni infection (4). Although the 38,000 M,. antigen initially appeared as a good candidate for the molecular cloning and subsequent studies, the glycanic nature of the epitope recognized by the IPLSmI mAb limited its in vitro production by recombinant DNA methodology. Secondly, the 38,000 Mr antigen was shown (5) to bind the IPLSm3 mAb of IgG2c isotype capable of blocking both in vivo and in vitro effector function(s) of the IPLSmI IgG2a mAb. We recently demonstrated (6) the existence of similar blocking antibodies specific to the 38,000 Mr molecule