[Relationship between haptoglobin types and group G streptococci (author's transl)].

A relationship was found between the haptoglobin types of human sera and the agglutinability of some strains of group G streptococci. Sera with the haptoglobin types Hp 2-2 and Hp 2-1 agglutinate these streptococci to high titers, from 1:200 up to more than 1:6400. On the other hand, the sera with haptoglobin type Hp 1-1 agglutinate not more than up to titers of 1:16 (mostly lower). Out of 102 strains of group G streptococci only 3 showed this characteristic phenomenon. This study was undertaken in order to elucidate whether the Hp 2-2 and Hp 2-1 proteins have antibody activity. Incubation of Hp 2-2 or Hp 2-1 sera with antihaptoglobin antisera or with anti-Hp 2-antiserum did not change the agglutinating activity but the haptoglobin was eliminated from the sera. Absorption of Hp 2-2 and Hp 2-1 sera with these group G streptococci lowered the titers significantly but the haptoglobins are detectable as in the non-absorbed sera. Sera with haptoglobin 1-1 contain an inhibitor. Mixing of Hp 2-2 and Hp 2-1 sera with high agglutinating titers with Hp 1-1 sera (low titers) was followed by a significant decrease of the titer.