Aspects of the Immune Hemolytic Reaction

Summary

Sheep serum contains inhibitors that prevent the lysis of sensitized sheep red cells by guinea pig, pig or human C′, but do not interfere with the sensitization of the cells by rabbit antibody. The presence of a relatively large proportion of sheep serum during the formation of EAC′_1,4,2 by guinea pig C′ results in slight loss of C′1 and C′2 activities on these cells and no detectable change in C′4 activity. The inhibitors affect primarily the C′3 step. Sheep serum, however, lyses sensitized human erythrocytes, and human serum inhibits the lysis of type A human erythrocytes by sheep C′. These results suggest a reason why a given C′ may be less active in lysing sensitized homologous red blood cells.