blood types/hemagglutination assay

Hi. Can someone please help me with the following blood typing/hemagglutination assay problem. I'm confused about who is the donor and who is the acceptor.

For the question, please go to the following website: http://tutor.lscf.ucsb.edu/instdev/sears/immunology/

Click on prior examinations; password: gauchos

Go to winter 2000 midterm, question #3. (My professor gave out previous years' exam questions, but not answers.)

Here are my answers:

Initially, I assumed that the "serum from" column was a list of the acceptors and the "blood from" row was a list of the transfusion donors.

This is the only thing that makes sense to me because if it were the other way around, if the serum was the donor, how could type O be a universal donor? Type O blood has anti-A and anti-B antibodies in its serum, so if the serum is donated, Type O's antibodies would attack the host blood (unless it was also type O).

It also makes the most sense to be because you can separate a donor's donation into serum and pure blood and only donate the blood (with no antibodies). But you can't separate the acceptor's blood from its serum.

But elements of this question make me think that it IS the other way around -- that the serum column is the donor list and the blood column is the acceptor list. Can you help clear this up for me? And if I am wrong in my assumption, explain how type O can be a universal donor when it is donating antibodies along with blood?


A1) IF the serum is the acceptor and the blood is the donor, then bottle #1 is the only safe blood sample to use for a transfusion with Patient type A.

A2) IF the serum is the donor and the blood is the acceptor, then Patient type A can accept blood from either bottle 1 or bottle 3.


B1) If the serum is the acceptor and the blood is the donor, then bottle #2 is type B. The fact that the serum from Patient type A agglutinates with #2 indicates that #2 is either type B or type AB. (If it were type A or type O, it would not react with type A.) But type AB is a universal acceptor -- and the fact that the serum from #2 cannot accept blood from every donor indicate that it must be type B.

B2) If the serum is the donor and the blood is the acceptor, then bottle #2 is also type B, for similar reasons (I won't go into again to save time).

C1) If the serum is the acceptor and the blood is the donor, then there is no universal donor. None of the bottles are able to donate to all blood types without resulting in agglutination.

C2) If the serum is the donor and the blood is the acceptor, then bottle #3 is the universal donor, type O. It does not result in agglutination when mixed with any of the other blood samples, and it cannot accept a transfusion from any but its own blood type.

Thanks for your help!