Question

Which antibodies are found in the plasma of a person with type B blood?

• A. Antibody-A, but not antibody-B
• B. Neither antibody-A nor antibody-B
• C. Both antibody-A and antibody-B
• D. Antibody-B, but not antibody-A

Answer 1

The correct option is A Antibody-A, but not antibody-B

The plasma of different individuals contain two natural antibodies (proteins produced in response to antigens) namely A and B. If an antigen is mixed with its corresponding antibody then it leads to agglutination (clumping). Hence, blood groups with antigen B on its surface should not contain antibody B in its plasma. Therefore, person with B blood group has A antibodies and person with A blood group has B antibodies, whereas a person with AB blood group has no antibody and the one with O blood group has both A and B antibodies.

$\begin{array}{cccc}\text{Blood group}& \text{Antigens on RBCs}& \text{Antibodies in Plasma}& \text{Donor's Group}\\ \text{A}& \text{A}& \text{anti-B}& \text{A,O}\\ \text{B}& \text{B}& \text{anti-A}& \text{B,O}\\ \text{AB}& \text{A,B}& \text{nil}& \text{AB, A, B, O}\\ \text{O}& \text{nil}& \text{anti-A, B}& \text{O}\end{array}$