Allergic and irritant contact responses to DNFB in BN and LEW rat strains with different TH1/TH2 profiles

BN and LEW rats possess different and extreme profiles of TH1/TH2 cells. The main objective of this study was to determine if this constitutively expressed property may influence the propensity to develop contact allergy to a potent contact sensitizer, 2,4-dinitro-1-fluorobenzene (DNFB). In order to avoid overlapping reactions due to toxicity, we defined non-irritant threshold levels of DNFB histologically in ear skin, dorsal skin and oral mucosa prior to the sensitization experiments. Evaluation of the elicitation response was carried out by an invasive method (biopsy). LEW rats proved to express a more extensive challenge response to DNFB than rats of the BN strain. Further, epicutaneous sensitization with DNFB gave a better challenge response than the subcutaneous route regardless of rat strain. In ear skin, but not in oral mucosa, the response was more vigorous after five than after two exposures. Our results are discussed with respect to the possibility that the TH1 type cells may play a significant role in the development of experimental contact allergy.