Properdin and the Complement System The complement system has traditionally been regarded as the vital part of the body's initial protective mechanism against microbes. It also has some physiological functions, such as clearing immune complexes and aiding in the clearance of apoptotic bodies. More recent findings suggest that complement activation has a “governing function” (Rutkowski et al., 2010). Complement anaphylotoxins play a role in the development of redness, swelling, heat, pain, and loss of function, which presents an inflammatory response to any problem within the body (National Institute of Allergy and Infectious Diseases 2008). It facilitates this through adaptive immunity, enabling humoral immunity, eliminating apoptotic cells, regulating the coagulation system, synapse maturation, angiogenesis, mobilization of hematopoietic stem progenitor cells, tissue regeneration and metabolism of lipids (Pio et.al. p231). 50 surface-bound circulating proteins support these processes. There is a symbiotic relationship between proteins and the complement system as complement activation results in the activation of these proteins. These proteins are vital as they also act as effectors, receptors, and checkpoints that facilitate equally widespread activation and inhibition of the system. Complement proteins are inactive while circulating in the blood. However, when the first protein in the sequence is activated, it starts moving according to the domino principle. Each element is activated sequentially and is involved in a precise order of phases which is called the complement cascade. The membrane attack complex inserts itself into the gram-negative bacterial wall, the bacteria swells and is destroyed. Other elements of complement pre...... middle of paper ...... development of CD8+ T cells. At the fourth stage, CD4+ T and more specified T cells attack the tumor origin in the body (Pio et al., p238). Through the help of cytolytic T lymphocytes, antigen-bearing tumor cells that remain at the site are destroyed (Scheiber, 2011). In some cases there are tumor cells that survive the elimination phases. In the equilibrium phase, lymphocytes and IFN-gamma exert pressure on unstable and highly mutant tumor cells. Variants that survive the elimination phase enter the escape phase. At this point, cancer cells continue to grow rapidly and can lead to defects in the human body. The first reason would be the loss of antigens which would then lead to a low immune system to identify the presence of tumor cells. Another reason may be unexpected resistance to the impact of cytotoxic immunity (O'Sullivan, 2012).