SUPPRESSION OF DELAYED-TYPE CONTACT SENSITIVITY IN THE MURINE ORAL-MUCOSA BY PRIOR INTRAGASTRIC ADMINISTRATION OF HAPTEN

The effect of intragastric administration of antigen on the developmen t of a mucosal cell-mediated immune response has been examined in a mo use model. Feeding mice with picryl sulfonic acid (PSA) abrogated deve lopment of buccal delayed-type contact hypersensitivity (CS) responses upon buccal challenge with picryl chloride (PCl) in animals that had previously been sensitized in the oral mucosa In contrast, such feedin g had no effect on buccal CS reactivity in animals similarly challenge d but sensitized at skin sites. Conversely, gastric administration of PSA suppressed PCl-induced skin CS reactivity in skin-sensitized anima ls but had no effect on skin CS reactivity in buccally sensitized mice . Enterically induced suppression of buccal mucosa CS reactivity was a ssociated with marked reductions in the numbers of infiltrating CD11b( +) macrophages and CD4(+) cells, and a virtual disappearence of CD8(+) cells in buccal tissue specimens examined 24 h after local challenge. Thus, depending on the initial site of immune sensitization, oral ant igens may also suppress mucosal T cell reactivity.