ABO blood group system B, and AB blood into type O. This is done by using glycosidase enzymes from specific bacteria to strip the blood group antigens from red blood cells. The removal of A and B antigens still does not address the problem of the Rh blood group antigen on the blood cells of Rh positive individuals, and so blood from Rh negative donors must be used. Patient trials will be conducted before the method can be relied on in live situations. Another approach to the blood antigen problem is the manufacture of artificial blood, which could act as a substitute in emergencies.
Blood type (non-human) S, and Z polymorphisms. Blood type (non-human) Animal erythrocytes have cell surface antigens that undergo polymorphism and give rise to blood types. Antigens from the human ABO blood group system are also found in apes and Old World monkeys, and the system traces back to the origin of hominoids. Other animal blood sometimes agglutinates (to varying levels of intensity) with human blood group reagents, but the structure of the blood group antigens in animals is not always identical to those typically found in humans. The classification of most animal blood groups therefore uses different blood typing systems to those used