Proteolytic cleavage of IgG bound to the Fc receptor of Schistosoma mansoni schistosomula.

After the binding of IgG to the surface Fc receptor of Schistosoma mansoni schistosomula, the Fab portions of IgG are cleaved and small peptides are liberated in the culture medium. At least two types of proteinase activities have been demonstrated in the secretory products of schistosomula. One is an endoprotease with trypsin-like activity, with an optimum pH of 7 and an optimum temperature of 45 degrees C. The other is a metalloaminopeptidase with an optimum pH of 7 and temperature of 37 degrees C.