A powder from dried human erythrocyte stromata was prepared to determine whether normal autoantibodies could be recovered from unsensitized erythrocyte powder and to study some of the properties of anti-A, anti-B and anti-Rho(D) antibodies recovered from sensitized powder.
Twenty-five samples of unsensitized erythrocyte powder of all ABO blood groups were tested. The amount of eluted powder was as great as 200 mg., representing about 25 ml. of packed red cells. In no instance could antibody be detected in the eluates. This negative finding could be explained in three ways: by lack of antibody production, in disagreement with Landsteiner’s rule; by neutralization of antibody by a corresponding antigen before it reached the circulation; or by immediate elimination of sensitized erythrocytes from the circulation.
The eluate of A erythrocyte powder sensitized with O serum agglutinated both A and B red cells. After neutralization with A polysaccharides, the anti-A antibody disappeared and anti-B remained. These experiments appear to support the theory of the multispecific character of natural antibodies.
Rh-positive erythrocyte powder was sensitized with an incomplete anti-D (anti-Rho) serum and eluted in saline. The eluate did not agglutinate Rhpositive cells, but sensitized them for the action of Coombs’ serum. The mixture of Coombs’ serum with the eluate also produced agglutination of Rh-positive cells. These phenomena are explained as being due to the lack of or the very small amount of ballast proteins in the saline eluate.