Antigens shared by thymic stromal cells and T lymphocytes are abnormally expressed in AKR thymuses.

Accumulating evidence has shown that thymic stromal-lymphoid interactions play a major role in the development of AKR thymic leukemia. A normal thymic stromal cell (TSC) line B6TE-A, which has been shown to support the in vitro growth of AKR leukemic T cells by forming multicellular complexes with them, was used to raise monoclonal antibodies. Three of these mAb, MTS 31, 32 and 38, in addition to 2 other MTS mAb, are abnormally expressed in the preleukemic and/or leukemic stages in AKR mice. These 5 MTS mAb, which detect antigens on both subpopulations of TSC and T cells, show some reduced cortical reactivity from the pre-leukemic period (MTS 32 and 35) to markedly depressed reactivity in the leukemic period (MTS 31, 32, 33, 35 and 38). While it appears that the major reduction is due to the loss of antigens from the cortical thymocytes, there is some indication that the stromal elements may be affected also. In addition, MTS 29, which was also produced in this study, while only reacting with rare thymic medullary cells in situ was densely distributed on cultured stromal cells from both normal and leukemic thymuses. In this report, the value of these MTS mAb for documenting various stages of AKR leukemogenesis has been clearly demonstrated: their possible modulatory effects on in vitro T cell leukemia growth is currently being investigated.