This universal recipient have AB blood type, while universal donor has O blood type. A universal recipient means that this person has A and B antigenes on the surface of blood cell and no antibodies that could react with the donor’s erythrocytes. A universal donor has no antigens on the surface of their erythrocytes, so it doesn’t provoke the immune responce of the recipient.

If one person has A blood type, his erythrocytes will have only A antigene on their surface and anti-B antibodies in the plasma. A person that has an O blood type, doesn’t have any antigens that determine ABO system, but he would have both, anti-A and anti-B antibodies in the plasma. If the recipient has A and the donor has O blood type, the transfusion will be successful because erythrocytes of the donor don’t have antigens on their surface. However, if a person with O blood type is a recipient, his anti-A antibodies will induce immune response on A antigen that is present on the donor erythrocytes.

Erythrocytes have many protein molecules on their surface that can induce B lymphocytes in the making of the antibodies. These large proteins are called antigens and they determine the blood type. In the ABO blood type inheritance, we have three different alleles – A, B, and O, but we have four possible phenotypes – A (AA, AO), B (BB, BO), AB (AB), and O (OO) type of blood. A person with A blood type have only A antigen, but anti-B antibodies. Someone with B blood type will have B antigen and anti-B antibodies. A person with AB blood type is a universal recipient, which means that this person has A and B antigens but he doesn’t have anti-A or anti-B antibodies in their blood so their immune response won’t be activated by the transfusion. A universal donor has O blood type, he doesn’t have antigens on erythrocyte surface but it has both anti-A and anti-B antibodies.