How complement activation via a C3a receptor pathway alters CD4+ T lymphocytes and mediates lung cancer progression? —future perspectives

The complement system is characterized by proteins, which participate both in the innate immune response, opsonizing pathogens, and also in the adaptive immune response, inducing a cascade of inflammatory reactions. Produced by the liver, the highest concentration of complement proteins is found in the plasma and are sparsely in the intracellular spaces and in another body tissues (1-5). The origin of its name comes directly from its function as a “complement” to the antibodies’ antimicrobial reactions, activated by three basic pathways: classic, lectin, and alternative. Independent of one another, C3 and C5 are common points of activation of each pathway in the complement system (6-8).