Responsiveness of wild-type mice to immunization with purified RhD protein. A representative example is shown (n = 4). In contrast to the DR15 transgenic mice, wild-type mice (WT) of the same background strain immunized with RhD protein do not produce anti-RhD antibodies detectable by IELAT (A) or IAT (B). Splenocytes isolated from RhD-immunized wild-type control mice proliferate weakly in vitro in response to stimulation with the RhD protein (□) compared with DR15 transgenic mice (▪) (C).