In vivo protection against S. mansoni infection by monoclonal antibodies.

A monoclonal antibody of the IgG1 class (27.21), that was previously shown to be cytotoxic in vitro to the schistosomula, conferred partial protection in vivo against challenge infection with S. mansoni. Monoclonal antibodies of the IgE class (54.10) were not effective in these experiments, but were capable of causing specific degranulation of basophilic cells upon contact with the young larva (3-6 h). The relevance of the IgE antibodies to protection observed in immunized mice is discussed.