Migration of distinct subsets of CD8+ blood T cells through endothelial cell monolayers in vitro


The immune response in many infections and to allografts is dependent on CD8+ cytotoxic T lymphocytes (CTL). Influx of CD8+ CTL from the blood has been documented during antigen challenge. We have previously found that a subset of CD8+ T cells from normal blood can migrate through endothelial cell monolayers in vitro. To further characterize migration-prone CD8+ T cells from normal blood, we examined the expression of CD28 and a restricted epitope of CD18/CD11a (S6F1), a CTL marker. Although normal blood CD8(bright+) T cells were heterogeneous in their expression of CD28, three populations could be identified (CD28(low), CD28(moderate), and CD28(high). CD8+ cells migrating across endothelial cell monolayers were enriched for CD8(bright+) CD28(high) cells and a subset of CD8(dim+) cells, which were CD28(high). Both adherent and migrating CD8+ cells were exclusively (>95%) S6F1(high). There was also preferential adhesion and migration of CD8+ cells expressing the low molecular-weight form of the leukocyte common antigen, CD45RO. Cytokine activation of the endothelium did not significantly alter preferential migration of these subsets. These data suggest that certain subsets of CD8+ memory T cells in normal human blood are prone to, adhere to, and migrate through allogeneic endothelial cells and would thus be likely to be recruited to sites of antigen challenge.

Publication Title

Journal of Leukocyte Biology