Contact-sensitizing and tolerogenic properties of 2,4-dinitrothiocyanobenzene.

Epicutaneous application of 2,4-dinitrothiocyanobenzene (DNTB) is said to result in specific immunological hyporesponsiveness and fails to induce contact sensitization. However, we demonstrate that topical exposure to DNTB causes activation of the draining lymph node in mice and the induction of contact sensitization in both rodents and a single human volunteer. In mice and rats, pre-exposure to DNTB failed to impair subsequent responsiveness to the cross-reactive allergen 2,4-dinitrochlorobenzene. These data provide evidence that DNTB cannot be regarded as an exclusive tolerogen when applied epicutaneously and indicate that attempts to define the characteristics of tolerising chemicals from analysis of this agent may be misleading.