Schistosoma mansoni antigens differentially recognized by resistant WEHI 129/J mice

Abstract

Mice of the strain WEHI 129/J are genetically resistant to chronic Schistosoma mansoni infection. Resistance is expressed in at least 50% of mice, with the remaining mice showing normal susceptibility to infection. The serum antibody specificities in the resistant proportion of WEHI 129/J were analyzed at various times after exposure to cercariae by using Western blotting and immunoprecipitation. Comparisons with the susceptible proportion of WEHI 129/J and other permissive mouse strains revealed four antigens that were differentially recognized by resistant mice at various times of infection: Sm25, an M(r) 25,000 integral membrane protein of adult worms that was better recognized by resistant mice 40 to 50 days after exposure; Sm67, an M(r) 67,000 water-soluble antigen of adult worms that was better recognized by resistant mice at days 30 to 40; SM120, an M(r) 120,000 antigen expressed by cercariae and adults worm that was differentially recognized, although inconsistently, at days 20 to 40 postexposure; and Sm26, an M(r) 26,000 glutathione S-transferase that was uniquely recognized by resistant mice at day 20 in two of three experiments. Analysis of antibody specificities in (BALB/c x WEHI 129/J)F1 x WEHI 129/J backcross mice indicated that high responsiveness to Sm25 at days 40 to 50 correlated with resistance. The candidacy of these four molecules as vaccines for schistosomiasis mansoni is discussed.