The schistosomulum surface antigens ofSchistosoma haematobium

Abstract

Surface antigens ofSchistosoma haematobiumwere identified by¹²⁵I-surface labelling of schistosomula followed by immunoprecipitation of the solubilized, labelled surfaces. The major antigens, after electrophoresis, formed a continuous smear corresponding to a molecular weight in the range 35–24000; in addition, a 17000 antigen was also identified. These surface antigens, in contrast to somatic antigens, were species-specific, as judged by immunoprecipitation with human anti-S. mansoniserum and serum from mice vaccinated with highly irradiatedS. mansonicercariae.S. haematobiumsurface antigens, however, were recognized to some extent by serum from mice chronically infected withS. mansoni. It is suggested that this cross-reactivity may reflect the heterologous immunity demonstrated experimentally between these two species, whilst the species-specificity of vaccine sera to surface antigens may mirror the highly specific immunity induced by vaccination.