North Sea: North Sea, shallow, northeastern arm of the Atlantic Ocean, located between the British Isles and the mainland of northwestern Europe and covering an area of 220,000 square miles (570,000 square km).
Your immune system ignores the surface antigens on your own RBCs. However, your plasma contains antibodies, sometimes called agglutinins , that will attack the antigens on foreign RBCs. When these antibodies attack, the foreign cells agglutinate , or clump together; the process is called agglutination . The plasma of a Type A, Type B, or Type O individual always contains either antiâ A or antiâB antibodies, or both, even if the person has never been exposed to RBCs that carry foreign surface antigens. If you have Type A blood, your plasma contains antiâB antibodies, which will attack Type B surface antigens.
IgM is not only the first class of antibody to appear on the surface of a developing B cell. It is also the major class secreted into the blood in the early stages of a primary antibody response, on first exposure to an antigen.ntibodies defend us against infection by binding to viruses and microbial toxins, thereby inactivating them (see Figure 24-2). The binding of antibodies to invading pathogens also recruits various types of white blood cells and a system of blood proteins, collectively called complement (discussed in Chapter 25).