Isolation and antigen analysis of surface tegument membranes from schistosomula ofSchistosoma mansoni

Abstract

The outer tegument membranes of Schistosoma mansoni schistosomula have been removed by mechanical disruption in a hypotonic salt solution and partially purified by differential and sucrose density gradient centrifugation. Fractionation was monitored by measuring increase in specific activity of bound [125I]wheat-germ agglutinin (WGA), alkaline phosphatase and calcium-stimulated ATPase. Two-dimensional IEF/SDS polyacrylamide gel electrophoresis was used to analyse the peptide composition of the isolated membranes and to compare and contrast with lactoperoxidase/glucose oxidase surface labelled peptides. At least 35 surface-labelled peptides were resolved on the two-dimensional maps: all were also present in the membrane material recovered from the sucrose gradient. Western blot analysis demonstrated a marked heterogeneity in the antibody response of infected human patients to individual membrane antigens. The antigenic profile of membranes isolated from cercariae, 18 and 96 h schistosomula were compared using Western blots: some minor differences were observed between the three preparations.