To provide insight into bacterial suppression of complement-mediated immunity, we present here structures of a bacterial complement inhibitory protein, both free and bound to its complement target.

Complement component 3, often called C3, is an essential protein of the immune system. This protein plays a vital role in the body’s innate immune system, providing: the first line of defense against ...

Your complement system consists of a group of important proteins in your bloodstream. These proteins help your immune system fight off harmful invaders, such as bacteria, and other foreign substances.