Complement-like system in the mosquito responses against malaria parasites

The life cycle of malaria parasites is divided between the two hosts with distinct organization of immune responses. While the mammalian host employs innate and adaptive defenses to restrict Plasmodium proliferation, the mosquito vector is devoid of the powerful adaptive arm and relies solely on innate immune responses. The evolutionarily conserved complement system is a powerful innate immune mechanism of animal kingdom. It includes a series of secreted proteins that upon activation bind pathogens and promote their phagocytosis, direct lysis, and recruitment of immune cells. In particular, complement-like thioester-containing protein TEP1 is a major regulator of Plasmodium development within the mosquito vector. In this chapter, we will discuss biological and chemical properties of TEP1 and the role of its genetic polymorphism in shaping mosquito interactions with the malaria parasites.