The production of anti-A1 agglutinins in A-like rabbits injected with human group a1 secretor saliva.

A-like and non-A-like rabbits were injected with human group A1 and A2 secretor saliva. The sera were then examined for their agglutinative capacity against human group A1, A2, B and O erythrocytes before and after sequential adsorption with group O, B and A2 erythrocytes. The A-like rabbits produced specific anti-A1 agglutinins when injected with group A1 saliva but not when injected with group A2 saliva. The non-A-like rabbits produced anti-A and anti-A1 agglutinins in response to the A1 antigen but only anti-A agglutinins when group A2 saliva was injected. These experiments support the interpretation that a qualitative difference exists between subgroups A1 and A2. The non-A-like rabbits also formed cross-reacting antibodies as shown by the increase in the agglutinins reactive with human group B red cells.