Phenotypic characterization of CD4-/alpha beta TCR+ and gamma delta TCR+ T cells with a transendothelial migratory capacity.

During inflammation, both CD4+ and CD4- T lymphocytes extravasate into perivascular tissues by adhering to and migrating through the vascular endothelium. These studies were undertaken to characterize the phenotype of CD4- T cells that have a capacity to migrate through endothelium. Results show that CD4- T cells exhibit a greater capacity to migrate through endothelial cells (EC) than CD4+ T cells; and that TCR-gamma delta+ T cells exhibited the greatest migratory capacity. The migrating CD8+ T cell population was enriched in CD45RO+/L-selectin-/LFA-1bright/CD29bright/CD 44bright cells. TNF-alpha-activated EC did not support increased CD4- T cell transendothelial migration and changes in the phenotype of the migrating CD8+ T cells. The migrating CD4- T cell population was enriched in VLA-2+ T cells and expressed increased densities of VLA-4, VLA-5, and VLA-6. The migrating TCR-gamma delta+ T cell population contained both CD8dim and CD8- T cells. Moreover, the migrating gamma delta T cell population was not different from the initial or nonadherent population in that it contained CD45RO+, CD45RA+, and L-selectin+ cells. Finally, migrating TCR-gamma delta+ T cells contained cells expressing V delta 2 and V gamma 9 TCR chains, but these were not enriched compared with the initial population. These studies have characterized the CD4- T cells that are capable of transendothelial migration in vitro. The results are consistent with the conclusion that unique subpopulations of CD8+ alpha beta and CD8+ and CD8- gamma delta T cells gain access to inflammatory sites by virtue of their intrinsic ability to migrate across the endothelium.