Suppression of the Primary Rh Immune Response with Passive Rh IgG Immunoglobulin

Abstract
THAT passive immunity can block active immunity is an established concept dating from as early as 1909.1 The precise mechanism of the immunosuppressive action, however, is still not clearly understood, but it is now being intensely studied by many investigators.2 3 4 In 1960 we put this principle to use5 6 7 8 9 and initiated a program to determine whether initial immunization of Rh-negative mothers by Rh of fetal origin could be prevented by the passive administration of Rh antibody immediately after childbirth. At the same time, and quite independently, Finn and Clarke and their co-workers10 , 11 began similar experimental work. Our aims were as follows: . . .