KCl-Extractable surface antigens of Schistosoma mansoni: immunological characterization and applicability in immunodiagnosis.

A Schistosoma mansoni antigen preparation was obtained by extraction of adult worms with a 3 M KCl solution. An indirect immunofluorescence reaction on cryostat sections of adult worms showed that the extracted antigens mainly originated from the tegument. The complex antigenic composition of the tegument extract was shown by immunoelectrophoresis against serum from infected mice and immunized rabbits, which gave up to 9 and 17 precipitation lines, respectively. When we compared the use of adult worm antigens and the tegument antigen preparation in the DASS and ELISA tests for immunodiagnosis of human schistosomiasis, the average sensitivity of the tests with the two preparations was about equal, although considerable differences between individual sera occurred. Analysis of tegument antigens, fractionated by gel filtration, showed that the main serological activity of the tegument antigen preparation was due to high molecular weight antigens.