Fig. 2

Analysis of HK cleavage by schistosomes using western blotting. a High molecular weight kininogen (HK) was incubated in the absence (-) or presence of parasites (S, schistosomula; M, males) for different time periods (6 or 24 h, as indicated). Samples were resolved by SDS-PAGE, blotted to membrane and probed by western blotting. A number of prominent HK degradation products are detected (at ~40 and 16 kDa, arrows) only in the presence of parasites. The numbers on the right indicate molecular mass markers (kDa). b Parasites or kallikrein, as indicated, were incubated with HK for 24 h and cleavage products were resolved by SDS-PAGE, blotted to membrane and probed for HK digestion by western blotting. Numbers represent molecular mass markers (kDa, right). c HK was incubated for 6 h with parasites either in the presence or absence of serine protease inhibitor PMSF (0.5 mM), as indicated (left panel); or in the presence or absence of cysteine protease inhibitor E64c (0.1mM) (right panel). The presence of PMSF (left panel) does not impede parasite-mediated cleavage of HK. The characteristic ~40 kDa product is indicated by the arrow. In contrast, the presence of E64c (right panel) does impede parasite-mediated cleavage of HK