Neuroendocrine Control of the Immune Response During Helminth Infections

The physiological interactions during the course of the immune response to helminths are complex. As our understanding of the neuroendocrine system grows, it has become increasingly clear that this complex network of neurotransmitters, hormones, and cytokines plays an important role in mediating immunity. Helminths present an especially complex relationship between parasites and their physiological systems, with neuro and hormone dependent host factors such as sex, age, and physiological status that correlate with parasite success. On top of the effect that this particular type of parasite may have on the invaded host, recent experimental evidence suggests that helminth parasites not only actively evade immune response, but are also able to exploit the hormonal microenvironment within their host to favor their establishment, growth and reproduction. Additionally, the close interaction of the worm with the host’s homeostatic systems, the molecules produced by them, and the activation of immune mediated mechanisms to eliminate it, activate a complex neuroendocrine network, that produces strong behavioral changes in the infected host. Understanding how the host neuroendocrine system can, under certain circumstances, favor the establishment of a parasitic infection, opens interesting perspectives into the host parasite relationship. This chapter focuses on the hostparasite neuroendocrine network activated by parasitic worm infections.

Keywords: Helminthes, immunoendocrine, neuroimmune, neuroimmunoendocrine, network, parasite infections, neurotransmitters, cytokines, sex steroids, behaviors, parasites, immune response, hormones, modulation, Th1, Th2, Th17, immunoregulation.