Genetic susceptibility of rats to some forms of delayed hypersensitivity.

The F1 generation, produced by mating Wistar rats from the Tuck colony which react to dextran (R rats) with Wistar rats from the NELP colony which do not react (NR rats) all responded to dextran with an anaphylactoid oedema reaction, and developed arthritis after adjuvant injections (AIA), but failed to show ovalbumin-induced delayed hypersensitivity reactions (OA) and experimental allergic encephalomyelitis (EAE). Back-crossing the F1 generation with NR rats produced animals, only half of which responded to dextran, though all the offspring reacted well to AIA, but poorly to OA and EAE. This confirms that resistance to AIA is not associated with resistance to dextran.