Modulation of suppressor mechanisms in allergic contact dermatitis: 1. Effect of C. parvum on the induction phase of contact allergy.

The effect of a pretreatment with corynebacterium parvum (C. parvum) on contact allergy in BALB/c mice was studied. Mice sensitized with 50 microliter (supraoptimal dose) 2.4-dinitrofluorobenzene (DNFB, 0.5%) showed a suppressed response as measured by ear swelling after painting the right ear with 0.3% DNFB in comparison to an allergic response obtained with an optimal sensitization dose (15 microliter DNFB 0.5%). By transfer of spleen cells from donors sensitized with a supraoptimal or an optimal dose to recipients either challenged ro sensitized shortly afterwards with DNFB it could be shown that less functionally active immune T-lymphocytes of the delayed hypersensitivity type and significantly more suppressor T-cells were induced in supraoptimally sensitized mice in comparison to the optimally sensitized animals. Intraperitoneal injection of C. parvum (2.8 mg/mouse) one week before sensitization enhanced the contact allergic response in mice sensitized with a supraoptimal dose of DNFB, with little effect on the response in optimally sensitized animals. Further analysis of this enhancement in transfer experiments showed that C, parvum selectively suppressed the generation and/or functional expression of T-suppressor cells and, probably by this mechanism, increased the number of functionally active T-immune lymphocytes. It is proposed that possibly by activation of the immune system C. parvum will suppress suppressor cells in contact allergy and by this mechanism might facilitate sensitization to the contact allergen.