The developmental expression of cysteine proteinases in Schistosoma mansoni

In this study several probes were used to identify and characterize cysteine proteinases (CP) from Schistosoma mansoni developmental stages. Proteinase activity was detected in all developmental stages using fluorogenic substrates. Specific activity was 4- to 11-fold higher against CBZ-phe-arg-AFC than against CBZ-arg-arg-AFC. A 32 kDa S. mansoni CP (Sm32) was identified in all stages by the radiolabelled active site CP inhibitor, CBZ-[I-125]tyr-ala-CHN2. A second CP, of 31 kDa (Sm31) was only detected in adult worms, primarily female worms and late schistosomula. Monoclonal antibodies for Sm32 and Sm31 reacted with homologous CP only in adult worms and late schistosomula. This study defines the developmental expression of CP activity in S. mansoni.