Human dermal microvascular endothelial cells support t lymphocyte migration

Lymphocyte migration into perivascular tissue is a fundamental property of specific T cell subsets. To date, the examination of the transendothelial migration of T cells have utilized endothelial cells (EC) isolated from large vessels, such as HUVEC. To determine whether microvascular EC similarly support the extravasation of T ceils, dermal EC (DEC) were isolated and cultured from neonatal foreskin. Subsequently, the DEC were transformed, cultured in selection medium, and then maintained in continuous culture in growth medium for 3 months before use in assays. The cells expressed EC specific determinants including CD31 (100% positive) and von Willlebrand factor (97% positive). Examination of the DEC by flow cytometry indicated that they constitutively expressed the adhesion receptor ICAM-1 (CD54), but not VCAM-1 (CD 106) or Eselectin (CD62E). When, however, DEC were exposed for 4 hours to the proinflammatory cytokine, TNFa, greater than 90% of the cells were Eselectin positive. Fewer activated DEC expressed VCAM-I (50% positive). Unlike TNFa, IL-lβ did not stimulate VCAM-1 expression although ICAM-1 and CD62E were upregulated. In functional assays, microvascular DEC facilitated the binding and migration of T cells similarly to HUVEC. Thus, EC isolated from the dermis, a common target of diverse inflammatory diseases, provide a relevant model for the examination of T cell extravasation into such sites.