ABO isoantibodies are of which class

Ans. is 'b' i.e., IgM The ABO antigens represent carbohydrate moeties present on erythrocytes. Invidual naturally develop antibodies (called isoantibodies), usually of IgM isotype, specific for ABO antigens that do not express. If the individual receives a transfusion of blood that contains incompatible ABO antigens, isoantibodies will cause agglutination of donor cells. This process is called as isohemagglutination, the antigens are called isohemagglutinins. Aslo remember Anti-Rh antibodies are of IgG class