The Agglutination of Human Erythrocytes in Antipneumococcal Sera

Abstract

Summary Type 14 antipneumoccal horse sera agglutinate human erythrocytes of all four major blood groups in high titers. Antipneumococcal horse sera for other types do not exhibit this phenomenon. The type 14 antipneumococcal horse sera, and occasional samples of type 5 and 7 horse sera, also agglutinate monkey and rabbit erythrocytes. The antirabbit agglutinins had the characteristics of cold agglutinins whereas the antihuman hemagglutinins were both warm and cold agglutinins. A large percentage of antipneumococcal rabbit sera, both those for type 14 and those for other types, have agglutinins for human red blood cells of groups AB and A and agglutinins and hemolysins for sheep red blood cells. The antihuman hemaggltuinins in type 14 horse sera and in the various antipneumococcal rabbit sera are not associated with hemolysins for the corresponding erythrocytes. All the agglutinins for the human erythrocytes in type 14 sera can be removed by sufficient absorption with heat-killed type 14 pneumococci. The agglutinins for human erythrocytes of all types can be removed from type 14 antipneumococcal horse sera by sufficient absorption with human erythrocytes of any one blood group. Large amounts of erythrocytes are necessary to accomplish this. Absorption of type 14 antipneumococcal sera with sufficient amounts of human erythrocytes to absorb all the human hemagglutinins removes only a portion of the type 14 pneumococcal agglutinins. The human group-A agglutinins in antipneumococcal rabbit sera may be reduced appreciably by absorption with sheep red blood cells. The reverse, however, is not true. Absorption with human group A cells does not materially alter the power of the antipneumococcal rabbit sera to agglutinate or to hemolyze sheep red blood cells. The possible relation of these findings to certain fatal reactions and to the hemoglobinuria observed following the injections of type 14 antipneumococcal horse sera is discussed.