Body Fluids and Circulation Question 6
6. Person with blood group $AB$ is considered as universal recipient because he has:
[2014]
(a) both $A$ and $B$ antigens on $RBC$ but no antibodies in the plasma.
(b) both $A$ and $B$ antibodies in the plasma.
(c) no antigen on RBC and no antibody in the plasma.
(d) both $A$ and $B$ antigens in the plasma but no antibodies.
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Answer : a
Hints & Solutions
(a) Karl Landsteiner first reported $ABO$ blood groups in human beings. $A, B$ and $O$ blood groups were discovered by Landsteiner in 1900 while $A B$ blood group was found out by de Castello and Steini (1902). ABO blood groups are determined by the gene I (isoagglutinin). There are three alleles $-I^{A}, I^{B}$ and $I^{O}$ of this gene. Proteins produced by the $I^{A}$ and $I^{B}$ alleles are called $A$ antigen and $B$ antigen. Individuals with $A B$ blood group have both antigen $A$ and antigen $B$ on their RBCs, and no antibodies for either of the antigens in their plasma, so they can receive blood from any blood type. The concepts of universal donor and universal recipient are more for simplicity sake as ideally only blood group matched unit is transfused. As red blood cells of blood group O-negative carry ’no antigen’, it can be given to any other group and is thus called universal donor.
