DISTRIBUTION OF ANTIGEN-SPECIFIC MEMORY T-CELLS IN LYMPH-NODES AFTER IMMUNIZATION AT PERIPHERAL OR MUCOSAL SITES

The distribution of antigen-specific memory T cells in different lymph nodes of sheep was determined using an antigen-specific in vitro prol iferation assay. Lymph nodes were collected from sheep immunized simul taneously with avidin or ovalbumin in a peripheral tissue site (hind l eg muscle) and keyhole limpet haemocyanin (KLH) in an intestinal tissu e site (gut wall or colonic mucosa). The results showed a consistently high proliferative response in typical peripheral lymph nodes (poplit eal and prescapular) and a low or negative response in gastrointestina l lymph nodes (abomasal and jejunal) while the response in other nodes was variable. The low proliferative response in the gastrointestinal lymph nodes was not due to the presence of supressor CD8(+) lymphocyte s and the proliferative response could not be raised to peripheral lym ph nodes levels with the addition to cultures of IL-2 or mitomycin-C t reated peripheral lymph node cells. The high proliferative response in the peripheral lymph nodes was not suppressed by the addition of mito mycin-C-treated gastric lymph node cells but was dramatically reduced by the addition of mAb against the IL-2-receptor or by depletion of CD 4(+) T cells. The results suggest that antigen-specific proliferative memory T cells, which may be Th1-like memory cells, preferentially mig rate to peripheral lymph nodes independent of their site of induction.