Chapter 25. Immunomodulatory phosphorylcholine-containing proteins secreted by filarial nematodes

Publisher Summary This chapter focuses on immunomodulatory phosphorylcholine (PC)-containing proteins secreted by filarial nematodes. The filariids are arthropod-transmitted nematode worms that parasitize a wide range of vertebrates including man. Infection in humans is long-term and hundreds of millions of people are infected with these parasites. The longevity of these worms is readily explained by the immunomodulation theory as “defects” in immune responsiveness are revealed in infected individuals. Some discrepancy exists as to the exact nature of these defects but generally, they incorporate impairment of lymphocyte proliferation and bias in production of both cytokines. All filarial nematodes examined to date have been found to actively secrete proteins that contain a PC moiety. These molecules can be found in the bloodstream of individuals infected with filarial nematodes. The immunomodulatory properties of PC on filarial nematode molecules are elaborated in the chapter. PC capability of inhibiting lymphocyte proliferation by modulating associated effects on signal transduction pathways is described and mechanisms of action of PC are explained. Attachment of PC to filarial molecules as a target for chemotherapy is also discussed.