The antigenic properties of red-cell globulin. 1

Three theories have recently been advanced relative to the nature of the antigen which, on repeated injection of foreign red cells, gives rise to a specific hemolytic sensitizer in the blood stream of the immunized animal. Balls and Korns 2 have come to the conclusion that the antigen is contained in the stroma of the red cell and that it is neither a globulin nor an albumin but probably a nucleoprotein. While the presence of nucleic-acid residues in non-nucleated red cells cannot be denied, the careful work of Bloor 3 indicates that within the limits of experimental error of his method the presence of nucleoprotein in red cells appears doubtful. The experiments of Wooldridge 4 on the constituents of the stroma of red cells shows that although a protein combined with a molecule containing phosphorus (this may be lecithin) is present in small quantities, the greater part of the protein fraction consists of paraglobulin.

While it is not to be denied that immunization with stroma does lead to the appearance of a hemolytic sensitizer, the experiments of Ford and Halsey 1 as well as those of Bennett and Schmidt 2 nevertheless indicate that it is also possible to obtain a hemolytic sensitizer by immunization with the water-soluble portion of red cells. Moreover, the findings of Balls and Korns that the filtrate obtained by passing a solution of hemolyzed red cells through a porcelain filter does not bind hemolytic sensitizer do not appear to us as conclusive evidence that the antigen is contained wholly in the stroma. It is a well-known fact that the first portion of the filtrate obtained on passing a solution of proteins such as serum through a porcelain filter invariably shows a loss of protein and that the latter portions of the filtrate are relatively richer in protein than the first.