On Anti‐M in Horse Sera

Discussion and Summary The unexpected findings of an N or N‐like factor in horse red cells as revealed in tests with extracts of Vicia graminea and the presence of the corresponding anti‐M as a naturally occurring antibody serve as another example of the Landsteiner rule of reciprocal relationship of agglutinogen on the erythrocyte and corresponding reciprocal antibody in the serum. Still another illustration of the Landsteiner de was shown by Celano, Levine and Lunge in the case of rhesus blood [l]. Rhesus sera contain anti‐A and the presence of the expected B or B‐like factor in rhesus red cells could be shown by their capacity to yield eluates of anti‐B specificity after exposure to human anti‐B. Prior to this the presence of B‐like material had been shown only in monkey saliva. Other examples in human blood are the regular occurrences of anti‐H in the serum of the Bombay type of blood, Oh [S], and the presence of anti‐Tj a in all individuals of type Tj b Tj b [3]. The elution technique serves as an additional powerful tool in recognizing instances of the original Landsteiner rule of reciprocal relationship between the presence of antigens on the red cell and the corresponding reciprocal antibody in the serum. Without the elution technique it was necessary to depend upon the study of secretions of the ABO antigens. In the case of man in whom about 20% are non‐secretors, an uncertainty in individual cases may arise. The ready response of the two horses in producing more anti‐M was to be expected once the naturally occurring anti‐M was demonstrated. Reagents are now available to test for the presence of N or N‐like factor in the red cells of donkey and mule ‐ the product of horse and donkey cross ‐ and other species related to the horse as well as those related to the pig and goat. It is to be expected that systematic studies of these red cells with a variety of anti‐N reagents including that found in extracts of Vicia graminea and other seed extracts (Mähelä) [6] may reveal findings of evolutionary significance. Résumé A l'aide d'extraits de vicía graminea les auteurs purent démontrer dans les érythrocytes de chevaux un agglutinogène semblable au facteur N. IIs entreprirent à la suite de rechercher dans le sérum de tels chevaux la présence d'agglutinines naturelles anti‐M, ce qui réussit. En immunisant les animaux avec des érythrocytes humains OM, ils purent sensiblemeat rehausser le titre des anticorps anti‐M. Les érythrocytes de Macacus rhésus contiennent un agglutinogène semblable au facteur M. Cependant, dans le sérum de ces animaux il ne se trouve point d'anti‐N naturel. A la suite d'injections de globules humains et equins de groupe N, de faibles agglutinines anti‐N firent leur apparition. Zusammenfassung Nachdem es gelungen war, mit Hilfe von Vicia graminea Extrakten in Pferdeerythrozyten ein N‐ähdiches Blutgruppenantigen nachzuweisen, war es naheliegend, entsprechend der Landsteiner'schen Regel Pferdeseren auf den Gehalt an Anti‐M‐Antikörpern zu untersuchen. Tatsachlich gelang es, in den Seren jener Pferde, deren Erythrozyten das N‐ähnliche Antigen enthielten, natürliche Anti‐M‐Antikörper nachzuweisen. Durch Immunisierung dieser Pferde mit rnenschlichen OM‐Erythrozyten gelang es, den Titer der Anti‐M‐Antikörper zu steigern. Die Erythrozyten von Rhesusaffen enthalten ein M‐ähnliches Antigen. Im Serum dieser Affen fehlen natürliche Anti‐N‐Antikörper. Nach Immunisierung der Affen mit N‐Erythrozyten von Mensch und Pferd gelang es hingegen, in ihrem Serum schwache Anti‐N‐Antikörper nachzuweisen.