Inactivation of rat macrophages by peptides resulting from cleavage of IgG by shistosoma larvae proteases

We have previously reported that IgG molecules bound to the surface Fc receptors of S. mansoni schistosomula were hydrolyzed by parasite enzymes. In this paper, it is shown that the hydrolyzed peptides inhibit macrophage stimulation, assessed by β-glucuronidase release or glucosamine incorporation, and also reduce both phagocytosis of latex beads and IgE-mediated macrophage cytotoxicity against schistosomula.This original process might represent an efficient immunosuppressive mechanism of the parasite to escape the host response.