Inhalation exposure to respiratory sensitising chemicals down-regulates guinea pig IgE and pulmonary responses.

Inhalation exposure of the guinea pig to the respiratory sensitising chemicals trimellitic anhydride (TMA) or diphenylmethane di-isocyanate down-regulated the IgE antibody response to subsequent systemic challenge with alum-precipitated hapten-protein conjugate. The suppression was isotype and hapten specific, challenge with unrelated hapten-protein conjugate resulting in high-titre IgE and IgGl antibody responses. Preliminary results indicate that the down-regulation of the IgE response to TMA markedly reduced the capacity of the animals to undergo a bronchoconstriction response following challenge with an aerosol of TMA, suggesting that the initial route of exposure may have profound effects upon the development of occupational respiratory allergy.