SELECTIVE ENDOTHELIAL BINDING OF INTERLEUKIN-2-DEPENDENT HUMAN T-CELL LINES DERIVED FROM DIFFERENT TISSUES

The ability of lymphocytes to recognize and bind to high endothelial venules (HEVs) is essential for lymphocyte migration from the blood into lymphoid tissues and into sites of inflammation. Endothelial cell binding capacity also critically determines the clinical usefulness of T-cell lines and clones in immunotherapy. In the present study, interleukin-2-dependent T-cell lines were derived from the blood, lamina propria of the gut, inflamed synovium, synovial fluid, and peripheral lymph nodes. After 3-8 weeks of culture, the expression of homing-associated molecules and binding to mucosal, synovial, and peripheral lymph node HEVs were analyzed. Cell lines derived from the blood and mucosal sites bound significantly better to mucosal and synovial HEVs than to peripheral lymph node HEVs. Three out of seven synovial T-cell lines showed preferential binding to synovial HEVs, whereas the rest bound almost equally well to synovial and mucosal HEVs. T-cell lines from peripheral lymph nodes bound preferentially to lymph node HEVs despite the lack of L-selectin (the peripheral lymph node homing receptor). Expression of the known homing-associated molecules did not predict the HEV-binding specificity of these lines. Importantly, two cell lines bound well to synovial venules, but poorly, if at all, to mucosal or peripheral lymph node HEVs, supporting the concept that synovial-specific HEV recognition mechanisms exist. In conclusion, the tissue origin of T-cell lines critically determines their selectivity for endothelial cell recognition, and besides the known "homing receptors," other molecules may also mediate tissue-specific HEV-binding of interleukin-2-activated T cells.