Antigenicity of Erythrocytes as Analyzed in Terms of Their Cross-Reactivity

Abstract

The antigenicity of human erythrocytes of four different ABO blood groups and sheep erythrocytes of unknown blood type from different individual sheep were analyzed in terms of their cross-reactivity with antibody-producing cells (plaque-forming cells, PFC) and serum antibody in immunized C57BL/6 and C3H/He mice. The antigenicity of human erythrocytes of different ABO blood groups in the C57BL/6 mice, as determined by the number of specific PFC, was, in decreasing order, AB= A> B=O (p<0.005). The efficiency of immunogenicity of the human erythrocytes in terms of their cross-reactivity with PFC was, in order, AB= A= B>O, and the degree of reactinogenicity was, in order, AB> A ≥ B > O. The order of antigenicity of sheep erythrocytes from different animals, SRBC #1-#6, was #1 (= #2) > #3 = #4= #5> #6 in C57BL/6 mice and #1= #2 = #3= #4= #6> # 5 in C3H/He mice, determined by the number of specific PFC (p<0.01). The cross-reactivity of SRBC #1 -#6 with PFC demonstrates that the order of immunogenicity of SRBC was #1= #2= #3= #4= #5> #6 in C57BL/ 6 mice and #1= #2= #3 = #4 = #6 > #5 in C3H/He mice, and that of their reactinogenicity was #1> #2= #3= #4= #5 > #6 in C57BL/6 mice and #1>#4=#6>#2=#3>#5 in C3H/He mice. The cross -reactivity at the antibody level was indicative of the immunologic characteristics of blood cells of low antigenicity (human group O erythrocytes and SRBC #5 and # 6). SRBC #5 and #6 were somewhat opposed to each other regarding antigenicity in C57BL/6 and C3H/He mice. This signifies the presence of different immunogenic components on SRBC #5 and #6. The production of anti-SRBC #1 antibody reached its peak on the third day after secondary immunization. That of anti-SRBC #1, cross-reactive with SRBC #6, occurred after a longer latent period, reaching its peak on day 6. This indicates that SRBC #1 possesses more than one kind of immunogenic component or immunogenic determinant group on its surface.