Type 2 T-cell-independent murine immune response to the human AB0 blood group antigens.

The human AB0 blood group determinants are simple carbohydrate structures which are widely distributed in nature. Much work has been done on the structure of the A and B antigens but little is known on the regulation of anti-A and anti-B immune responses. To develop a model system, we have characterized the AB0 immunity of normal Balb/c mice and found a significant level of serum natural anti-A but almost no anti-B. This finding and the known IgM predominance among immune anti-A produced in the Balb/c mouse indicate that the AB0 immunity of this mouse strain is comparable to the one of human blood group B individuals. Following immunization with human red blood cells, similar levels of anti-A were produced in normal and athymic Balb/c mice showing that the anti-A response is T cell independent. Furthermore, no anti-A or anti-B antibodies were produced in CBA/xid mice indicating a type 2 T-cell-independent immune response. These results may contribute to a better understanding of human AB0 responses and establish the mouse as a suitable model to study the immunobiology of AB0 antigens.