Robert S. Evans

Rh Antigen and Hapten. Nature of Antigen and Its Isolation from Erythrocyte Stroma

Summary 1. It has been demonstrated that the Rh antigen is quite different in character from the A and B substances as found in stroma from human erythrocytes. The Rh factor is particularly sensitive to thermal inactivation and is destroyed by a few minutes exposure to 56°C while the A and B substances remain intact. The inactivation by heat in the presence of moisture and the absence of oxygen suggests protein denaturation as the basis for its destruction. 2. Erythrocyte stroma has been fractionated into 2 parts; (1) a protein previously described and called stroma tin, and (2) a new lipoprotein which we call elinin. The Rh specificity is associated with the elinin. 3. An ether-soluble fraction has been separated from elinin which is characterized by a higher content of the Rh factor and a lower content of A and B substances. The Rh substance present in the ether solution which inhibits the anti-Rh serum showed an increased thermostability.

Production of Positive Antiglobulin Serum Test in Rabbits by Intraperitoneal Injection of Homologous Blood.

Summary (1) Three of 12 rabbits receiving intraperitoneal injections of blood immediately after removal from the heart developed a transiently positive antiglobulin serum test (Coombs test) with a reagent made by injecting rabbit serum into guinea pigs. None of the 3 developed evidence of a hemolytic anemia. (2) Rabbits receiving injections of rabbit red cell stroma which had been incubated with bacterial filtrate or emulsions of rabbit liver or kidney failed to develop positive agglutination tests with the same reagent.

Studies on antigens of human red cells. II. Serological properties of Rh factor in elinin.

Summary 1. Elinin, a lipoprotein fraction of the red cell exhibiting Rh activity has been isolated in relatively pure form largely by physical methods. 2. Injection of elinin from Rh positive cells into animals has so far failed to yield a measurable titer of anti-Rh antibodies. 3. Injection of elinin into human subjects who have been sensitized to the Rh factor by pregnancy or transfusion failed to increase the titer of Rh antibodies in the serum. Two of the subjects injected showed subsequent response to injection of whole Rh positive cells. 4. Injection of 1 to 1.5 g of active elinin intramuscularly failed to effect a change in titer of circulating antibodies.