MURINE DENDRITIC EPIDERMAL T-CELLS (DETC) EXPRESS THE HEMOPHILIC ADHESION MOLECULE E-CADHERIN

Cadherins mediate homotypic intercellular adhesion in epidermis and ot her epithelia. E-cadherin is also involved in interactions between mur ine epidermal Langerhans cells (LC) and keratinocytes (KC). Dendritic epidermal T cells (DETC) comprise another subpopulation of epidermal l eukocytes. Using flow cytometry, we determined that DETC expressed lev els of E-cadherin similar to those expressed by LC and KC. DETC also a dhered similar to three-fold better to KC and E-cadherin-transfected f ibroblasts than to normal fibroblasts. Treatment of DETC with trypsin in the absence of calcium caused a loss of E-cadherin and resulted in an similar to 80% decrease in DETC-KC adhesion whereas treatment of DE TC with trypsin in the presence of calcium did not significantly affec t E-cadherin expression or DETC-KC binding. Thus, E-cadherin may be in volved in adhesion of DETC to KC. DETC are derived from TCR V gamma 3( +) thymocytes that transiently populate embryonic murine thymus. We de termined that TCR V gamma 3(+) thymocytes as well as other early (feta l day 16) TCR gamma/delta(+) thymocytes expressed E-cadherin; TCR gamm a/delta(+) (TCR V gamma 3(-)) thymocytes that developed later did not. These results indicate that cells of the T cell lineage can express E -cadherin, and suggest that E-cadherin may play a role in adhesion of DETC (and/or DETC precursors) to KC.