Complement proteins are a group of proteins found in the blood that play a crucial role in the immune system. They help the body identify and eliminate pathogens, such as bacteria and viruses, by marking them for destruction and promoting inflammation. This process enhances the ability of white blood cells to clear infections. These proteins work in a cascade, meaning that one protein activates another, leading to a rapid response against invaders. The complement system can also assist in the removal of damaged cells and support the overall immune response, making it an essential component of the body's defense mechanisms.