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Unformatted text preview: ANT H RB IO 161 ABO Blood Types The ABO system has three alleles (A, B, O) that code for the type of molecule on the surface of the red blood cells. The A and B alleles are codominant, and the O allele is recessive to both A and B. There are two antibodies in the ABO system: anti-A and anti-B. An antibody is a protein molecule that recognizes and binds to a foreign substance that has been int roduced into the organism. Antigens are the foreign substances invading the body which stimulate the production of antibodies. Antibody reactions 1. The anti-A antibody reacts to destroy A-type molecules (found in type A and AB blood). 2. The anti-B antibody reacts to destroy B-type molecules (found in type B and AB blood). 3. There is NO antibody for type O blood. Because there are no antibodies for type O blood it is considered the universal donor. I t can be int roduced into any blood type w ithout causing an antibody/antigen reaction (clumping of red bloods cells). Presence of antibodies 1. People with blood type A have the anti-B antibody. 2. People with blood type B have the anti-A antibody. 3. People with blood type O have BOTH anti-A and anti-B antibodies. 4. People with blood type AB have NO antibodies. Testing for blood types. The antigens present in a blood type help us find out which blood type someone has. 1. People with type A blood have the A antigen but not the B. 2. People with type B blood have the B antigen but not the A. 3. People with type AB blood type have BOTH the A and B antigen. 4. People with type O blood have NO antigens. Example: - The blood clumps when exposed to anti-A antibodies but does not clump when exposed to anti-B antibodies. This means the blood contains A antigens but not B antigens and therefore is type A blood. ...
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- Spring '10
- ABO blood group system