Soluble adult worm
antigens (SWAP) of Schistosoma mansoni were fractionated by fast
protein liquid chromatography (FPLC) system, using Q-
Sepharose anion-exchange resin, in order to characterize antigenic fractions that may elicit cell responses in human
schistosomiasis. SWAP fractions were eluted by 20 nM Tris-HCl
solution (pH 9.6) with an increasing gradient of 1 M NaCl. The FPLC system was able to resolve 6 fractions, enumerated I to VI, according to the NaCl gradient. The analysis of each fraction on SDS-PAGE showed that fractions I to IV were constituted by multiple
protein bands with M, ranging from 21 to > 200 kDa. Large amounts of
nucleic acids were evidenced in fractions V and VI, as revealed by
ethidium bromide staining of
agarose electrophoresis
gels. Using ELISA, it was shown that sera from chronic
schistosomiasis patients contained
antibodies that recognized
antigens in practically all fractions. Studies were designed to investigate the capacity of these fractions to induce cell proliferation and
granuloma formation. It was demonstrated that fraction III stimulated significant proliferative response of peripheral blood mononuclear cells (PBMC) from chronic
schistosomiasis patients. However, fraction III coupled to
polyacrylamide beads induced small
granuloma formation in vitro, whereas beads coated with fractions I, II and V were able to induce significant
granuloma reactions.