👉 Heteroagglutinin is a protein that is found in the plasma membrane of red blood cells, which are a type of white blood cell. It is composed of two types of proteins: agglutinin and hemagglutinin. Agglutinin binds to antigens, while hemagglutinin helps to release antigens from the surface of the red blood cells. Heteroagglutinins are a type of protein that is found in the plasma