The areas where the antigen is recognized on the antibody are variable domains. Antibodies have an interesting Y-shaped structure withat least two binding sites for one specific antigen. They mediate the humoral immune response and are necesassary for the determination of self versus foriegn antigens. → Blood type AB has both A-antigens and B antigensĪntibodies (aka immunoglobulins) are proteins produced and secreted by differentiated B-lymphocytes called plasma cell.If we looking at the table below, we’ll see that: The antigens that are present on the surface of our red blood cells determine our blood type. The ABO blood typing is a naming scheme that states the presence or absence of just two antigens: antigen A and antigen B. Like other cells, our red blood cells may or may not have self-antigens present on their cell membrane. In the presence of foreign atnigens, proteins called antibodies attach to the antigens on the plasma membrane of the cell containing the antigen. The absence of this immune response very important and highly regulated, it prevents scenarios where the immune cells begin to attack host cells. Each of us has a unique set of self-antigens that do not trigger an immune response within ourselves.
For example, each of us produce a large number of self-antigens. However, not all antigens will provoke a response.
An antigen is a foreign or “non-self” macromolecule (typically a protein) that reacts with cells of the immune system.