Could inhibit the oxidative burst of leukocytes and neutralize the secondary products of lipid peroxidation, thus providing the resistance of these parasites to immune effector mechanisms and their persistence in the mammalian host. It may also be involved in the formation of cross-linking residues such as dityrosine, trityrosine and isotrityrosine identified in cuticular collagen. Highly cross-linked external cortex may also serve to protect the parasite from immune attack. 2 glutathione + H2O2 = glutathione disulfide + 2 H2O Homotetramer. Secreted into the cuticle and ultimately released into the medium. Up-regulated in the third stage larvae following infection of host. Concomitant synthesis occurs at a high level through the adult stage. Not detected in microfilariae. Belongs to the glutathione peroxidase family.