Factor B is a protein that plays a crucial role in the immune system, specifically in the complement system. It is involved in the activation of the complement pathway, which helps the body fight infections and clear damaged cells. Factor B works by binding to another protein called C3b, forming a complex that activates additional proteins in the complement cascade. This activation leads to a series of reactions that enhance inflammation, promote the destruction of pathogens, and facilitate the clearance of immune complexes. Proper functioning of Factor B is essential for maintaining a balanced immune response and preventing excessive inflammation or autoimmune reactions.