[Effect of protamine sulphate on erythrocyte agglutination by anti-rh antisera. Cause of time-dependence (author's transl)].

The effect of protamine sulphate on Rh antisera causes agglutination also in saline milieu and is time-dependent. Synchronous to the serologically demonstrable decrease of the protamine concentration a normalization of the immunoelectrophoretic picture (especially of the albumin arc) and a decline of the precipitate formation by heparin occur. These effects are based on enzymatic degradation of protamine by a protaminolytic enzyme contained in human serum. This enzyme could not be inhibited by sodium fluoride, sodium azide, ammonium oxalate, EDTA or alpha, alpha'-dipyridyl to a serologically desired degree. The change of the behaviour with regard to agglutination of human erythrocytes in the system Rh antibody - protamine sulphate results primarily from blocking acid groups on the erythrocyte surface and not from chemical modification of IgG antibodies. In this system protamine sulphate leads to the formation of agglutinates but it does not represent an obligate constituent of the formed agglutinate.