Question

A person with blood group AB has which of the following antigens in his RBCs ?

• A. A
• B. B
• C. A and B
• D. None of these

Answer 1

Answer: (C)

Karl Landsteiner reported first time ABO blood groups in human beings. $A,B$ and $O$ blood groups were discovered by Landsteiner (1900) while AB 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 AB blood group have both antigen $A$ and antigen $B$ on their RBCs and no antibodies for either of the antigens in their plasma.