Excretory-secretory products of helminth parasites: Effects on host immune responses

Abstract

Parasitic helminths excrete or secrete (ES) a variety of molecules into their mammalian hosts. The effects of these ES products on the host's immune responses are reviewed. Investigations into the source of antigenic or immunoregulatory ES products have identified the cuticular and tegumental surfaces of some nematodes and trematodes respectively as being important sources of ES products; other ES molecules are released through specialized excretory or secretory organs. It is proposed that the active shedding of surface antigens may serve as an important source of parasite antigens available to the immune system in a form in which they can be taken up and processed by antigen-presenting dend..