Temporal changes in the distribution of thoracic duct lymphoblasts to synovium and other tissues of rats with adjuvant-induced arthritis

The distribution of lymphoblasts (lymphocytes in cell cycle) obtained from the central lymph of donor rats and transferred adoptively to syngeneic recipients has been shown previously to be influenced by the presence of arthritis in either donor or recipient rats. The intent of the present study was to examine patterns of distribution of lymphoblasts in the early period after transfer, when extravasation of donor lymphoblasts was expected to occur. Thoracic duct lymphoblasts labelled in vitro with [(125) I]-iododeoxyuridine were detected in recipient rats by external radiometry and autoradiography. Irrespective of donor status, fewer donor lymphoblasts accumulated in the feet of normal recipients when compared to arthritic recipients at 15 min, 2 h and 24 h after cell transfer. When recipients of similar disease status were compared, the percentages of injected lymphoblasts from normal and arthritic donors recovered in the feet were similar at 15 min and 2 h after transfer. The proportions of lymphoblasts recovered in the feet at 24 h after injection declined in normal recipients and arthritic recipients of cells from normal donor rats. Importantly, this decline did not occur when both the donor and the recipient were arthritic. In the hindpaws, donor lymphoblasts were located predominantly in the bone marrow, except in transfers between arthritic rats, when at 24 h they were predominantly in the synovium. At 15 min, lymphoblasts were detected within the lumen of vessels within synovium, whereas by 2 h extravasation of these cells was evident. In conclusion, lymphoblasts accumulate more readily in hindfeet that are inflamed. In the early hours after injection, lymphoblasts from normal and arthritic donors are recruited equally, but these early levels are only maintained for 24 h in the combination of arthritic donor and arthritic recipient. A dramatic change in the proportion of lymphoblasts located in synovium at this later time suggests that a dynamic process of relocation, retention and/or local cell division maintains the numbers of arthritic donor cells in the latter combination.