Abstract
The presence of M and N antigens in the blood components other than the red cells and various tissues has not been settled yet. The elution method in combination with antiglobulin test reported by the present authors has been used for grouping the stains of the leucocytes, platelets, fibrin, and thymic lymphocytes. All of the test-stains showed obviously positive antigen activities which coincided with blood group of the sources. The experiments of the test-stains treated with trypsin revealed that the treated stains showed a similar agglutin-ability to that of the treated red cells. From the results, it is concluded that the blood components have M or N antigen activity which is a little lower than the red cells.
