Hapten-specific antibodies in allergic contact dermatitis in the guinea pig

A guinea pig model was used to investigate the potential role of hapten-specific antibodies in allergic contact dermatitis. Hapten-specific antibodies of both the IgG1, IgG2 and IgM (sub)classes could be readily detected by ELISA in sera obtained after single or repeated exposure to the allergens 2,4-dinitrochlorobenzene (DNCB) or 4-ethoxymethylene-2-phenyloxazolone. Experiments in which animals were strongly boostered with Freund's complete adjuvant support previous reports that hapten-specific antibodies are able to transfer contact skin reactions with a delayed time course into naive recipients. In contrast, epicutaneous sensitization procedures never allowed transfer of such reactivity. Upon transfer of immune sera to previously sensitized animals, existing allergic contact dermatitis was unaffected, except for a distinct suppression of induration, but not erythema, in the DNCB system. In actively sensitized animals, antibody-related suppression of induration was never observed. Hapten-specific hyposensitivity, as induced by repeated epicutaneous exposure, was also not related to circulating antibody levels. Our findings do not support the view that hapten-specific antibodies should be reconsidered as playing a potentially important role in allergic contact dermatitis.