PEPTIDE-SPECIFIC T-CELL CLONAL EXPANSION IN-VIVO FOLLOWING IMMUNIZATION IN THE EYE, AN IMMUNE-PRIVILEGED SITE

To visualize the primary antigen-specific T cell response to Ag introd uced into the eye, we have used an adoptive transfer system in which a limiting number of OVA peptide (323-339)-specific T cells from a TCR- transgenic mouse were transferred into nonirradiated, syngeneic recipi ents and then tracked in vivo by staining for FAGS analysis or immunoh istochemistry with the clonotypic mAb KJ1-26. Following posterior cham ber injection of Ag, KJ1-26(+) cells accumulated primarily in the drai ning, submandibular lymph node (LN) within 3 days, Although reduced in number, by day 6 these cells were primarily in the paracortical regio ns and were able to proliferate and secrete IL-2 in response to Ag sti mulation, In contrast, following i.v. injection of Ag, the KJ1-26(+) c ells accumulated in the paracortical regions of the LN to a comparable degree, but did not proliferate or secrete IL-2, The day 3 accumulati on of KJ1-26(+) cells in the submandibular LN was inhibited if the eye was removed within 5 h after injection of Ag. In the spleen, foci of KJ1-26(+) cells were observed in the periarteriolar lymphoid sheaths a t day 3; these were not observed to the same degree following other fo rms of immunization, These results demonstrate that the submandibular LN is the primary site for early clonal expansion of antigen-specific T cells following intraocular Ag administration and that these cells s how changes consistent with immunity rather than tolerance.