Effects of Contact Sensitization and Delayed Hypersensitivity Reactions on Immune Responses to Non-Related Antigens

Abstract

Guinea pigs were immunized intracutaneously into the ears with sheep red blood cells (SRBC). Application of a sensitizing dose of the contact allergen dinitrochlorobenzene (DNCB) onto the same ears was shown to suppress or enhance the humoral response to SRBC depending on the time of application. When guinea pigs were sensitized to a contact allergen, application of a sensitizing dose of a non-related allergen on the same ears either had no effect or caused a clear enhancement of the development of delayed type hypersensitivity (DTH). Strongest enhancement was found when both sensitizations were performed on the same day. Further experiments on the effects of a concomitant DTH reaction elicited at the site of application of a contact allergen showed a strong potentiation of DTH when B-cell suppression was minimized by pretreatment with cyclophosphamide (CY). It was considered that CY-DTH-immunopotentiation might be a useful tool for achieving a higher level of sensitivity after epicutaneous sensitization.

Does DNCB therapy potentiate epicutaneous sensitization to non-related contact allergens?

“…Topical application of DNCB in patients has been shown to increase PHA responsiveness of circulating lymphocytes (Cohen et al, 1974). In an experimental model Scheper et al (1976) observed that contact sensitization of guinea pigs with two different allergens, DNCB and oxazolotie, on the same day and at the same site markedly potentiated the delayed hypersensitivity reaction to the first sensitizer. According to the authors the underlying mechanism probably involves a central component operating in the draining lymph nodes, and a chemical inflammatory component enabling a more intensive peripheral sensitization.…”