Question

What type of blood contains A antibodies (but not B antibodies) in the plasma and lacks Rh antigens?

Answer 1

Simply put the answer of your question would be blood of the Rh negative B group.

Explanation:

When we talk about the type of blood, we are actually saying the antigenic features that are present in the RBCs( the Red Blood Cells). So a person with Blood group A has RBCs with antigen A in his blood. There are various antigens on the RBCs including the ABO antigens in which there are 2 antigen types( A type and the B type, O means none), the Rh antigen ( Rh short for Rhesus which is a type of monkey that it was discovered in), the Duffy antigen and other several minor ones.

These antigens when native to our body is normal and does not produce an immune response. But if introduced to a person in which those antigens are not native, they invoke an immune response forming antibodies. So for example, if a person with Rh negative blood type is given Rh positive blood s/he will form antibodies against the Rh antigens. However the Rh negative person who has never been introduced to Rh antigens will not have antibodies against Rh in his system.

But in case of the ABO antigens there is an exception. People with type A only blood type will have antibodies against the B antigen even if they have never been introduced to the B antigen previously. This is because soon after birth the large intestine is colonized by bacteria and these produce antigens are are similar to the A and B antigens. These invoke the immune response as said earlier causing the formation of the antibodies to whichever antigen that is not native to the baby.

So in summary:
1. Group A Rh +ve has: A antigen, Rh antigen, Antibodies against B antigen
2. Group B Rh+ve has : B antigen, Rh antigen, Antibodies against A antigen
3. Group O Rh+ve has: Rh antigen, Antibodies against A and B antigens
4. Group AB Rh+ve has: Both A and B antigen, Rh antigen, no antibodies against A or B
5. Rh -ve people have similar profiles but Rh antigens are absent but there are no antibodies against the Rh antigen.
Image: wikipedia.org