Differential ability of occupational chemical contact and respiratory allergens to cause immediate and delayed dermal hypersensitivity reactions in mice

Trimellitic anhydride (TMA) is known to cause occupational respiratory allergy associated with the presence of specific IgE antibody. Other chemicals, such as 2,4-dinitrochlorobenzene (DNCB), while exhibiting a clear potential for contact sensitization, apparently lack the ability to induce respiratory allergy in man. It has been shown previously that although both chemicals are immunogenic in mice, each provoking contact sensitization, exposure only to TMA results in an IgE antibody response. In the present study, to examine further the characteristics of human allergens, we have compared the ability of TMA and DNCB to elicit immediate and delayed cutaneous hypersensitivity reactions in mice. Topical exposure to both chemicals resulted in delayed (24 h) hypersensitivity. However, only TMA induced, in addition, an immediate (1 h) dermal reaction following local challenge. Serum from TMA-immune mice, but not from untreated mice or mice sensitized with DNCB, was able to transfer immediate hypersensitivity to naive recipients. The kinetics of passive sensitization with TMA-immune serum, together with the fact that immediate hypersensitivity to DNCB could be induced with monoclonal IgE anti-dinitrophenol (DNP) antibody, suggests that the immediate dermal responses caused by TMA are effected by hapten-specific IgE. These data demonstrate that different classes of occupational chemical allergen exhibit a variable potential to elicit immediate and delayed dermal hypersensitivity reactions in mice, and provide a novel approach to the classification and characterization of human allergens.