Light microscopic study of experimental cell-mediated immunity in rat oral mucosa.

A model for hapten-induced cell-mediated immunity (CMI) in the oral mucosa of the Sprague-Dawley rat is presented. Sensitization was performed with 0.1 ml of a hapten (DNCB 2%, in acetone solution) administered five times on shaved dorsal skin. Ten days after completed sensitization, eliciting doses of 0.1-0.02% of the hapten were applied in the buccal mucosa one or several times giving rise to an inflammation dominated by lymphocytes. The development of the reaction was studied in a time sequence study. Also sensitization through the buccal mucosa was attempted, with three or more of the eliciting doses applied directly in the buccal mucosa. Light microscopically, the reaction was identical to the one seen in previously sensitized rats. The effects of DNCB and DNFB on sensitized animals with eliciting doses of 25 microliter 2% or 0.02% in acetone/olive oil were compared. No differences were seen in the low concentration range, but in the high concentration range, DNFB showed a more potent effect giving rise to ulcers, not observed with DNCB.