SEX OF SCHISTOSOME CERCARIAE AS A FACTOR IN IMMUNIZATION OF RHESUS MONKEYS

A strong acquired resistance against challenge infection of Schistosoma japonicum or S. mansoni in rhesus monkeys was produced by previous immunization with either male or female cercariae of the respective species. In the case of S. japonicum, the immunizing cercariae can be either nonirradiated or irradiated human strain, or non-irradiated nonhuman strain. Qualitatively there was no difference in immunogenicity between sexes of schistosome cercariae. However, a possibility exists that quantitatively male schistosomula may produce more functional antigens than female schistosomula because the former are usually better developed and larger than the latter. © 1969.