Delayed-type hypersensitivity responses in mice treated with pertussis toxin and betamethasone.

Effects of pertussis toxin (PT) and betamethasone on delayed-type hypersensitivity (DTH) in mice were studied. When mice received PT (1 microgram/mouse) at the time of immunization or elicitation, a depression of DTH responses was observed. In addition, when mice received PT five days before and at the time of immunization, the DTH responses were suppressed. The administration of betamethasone along with PT at the time of immunization and elicitation caused an inhibition of DTH responses. These results suggest that PT depressed the DTH responses and that betamethasone suppressed such responses. Based on these findings, possible mechanisms by which PT and betamethasone affect DTH are discussed.