[Further investigations concerning the reaction between haptoglobin and T4-antigen-carrying streptocci (author's transl)].

The median level of haptoglobin types 2-2 and 2-1 was found to be proportional to the agglutination titer of T4 antigen-carrying streptococci (Fig. 1). This relationship need not exist in individual sera since, as seen from Table 1, high agglutination titers may be caused by sera with low levels of haptoglobin. Thus the agglutination reaction might depend not only on the quantity of haptoglobin but also on other factor(s) (at least in individual serum samples). - On the other hand, different agglutination titers did not correlate with the quantity of T4 antigen either. A strain of Strep. pyogenes, type 60, was agglutinated at high titers by sera with a high level of haptoglobin in spite of its low ability to absorb haptoglobin. This was in contrast to a strain of group G (20488) which had a high capacity both to become agglutinated and to absorb haptoglobin (Table 2). Absorption of haptoglobin by affinity chromatography decreased the agglutination titer for T4 streptococci. - The reaction between haptoglobin and T4-streptocci did not fix complement. No differences were found between sera of haptoglobin types 1-1, 2-1, and 2-2 with respect to the amount of C, C3, C4, and C3A, respectively (Tables 3-5).