Idiotypy of anti-Rh antibodies.

Anti-id sera to Rh antibodies were produced by injecting rabbits with purified Rh antibodies. These sera were shown to agglutinate O Rh+ RBC coated by the immunizing antibody and--in some cases--by other anti-D antibodies. Id and cross-reactive id were shown to be located in the antigen-binding and in the non-antigen binding regions of Rh antibodies. An unique example of evolution of idiotypic specificities on human antibodies has been reported. Lastly, we have demonstrated by rosette assay, presence on some PBL of receptors for Fab'2 anti-Rh coating O Rh+ red cells. Rosettes could not be obtained with lymphocytes of a donor and Fab'2 anti-Rh of another individual. Rosettes appeared at a period of time in which the amount of antibody was decreasing.