Collectins are a type of protein that play a crucial role in the immune system. They are part of the innate immune response and help the body recognize and eliminate pathogens, such as bacteria and viruses. Collectins can bind to specific sugars on the surface of these pathogens, marking them for destruction by immune cells. These proteins are produced mainly in the lungs and liver, and they include well-known members like surfactant proteins A and D. By enhancing the ability of immune cells to identify and respond to infections, collectins contribute to the body's defense mechanisms against various diseases.