Cell adhesion receptors of the integrin family play a major role durin
g re-epithelialization of human wounds. We have previously documented
that the expression of alpha v family integrins is induced in keratino
cytes of mucosal wounds [1]. In the present investigation, we extended
these studies to determine whether alpha v beta 6 integrin is express
ed during wound healing in humans. Mucosal and epidermal wound section
s from 1- to 7-day-old wounds were used for immunolocalization of inte
grins and their putative ligands. In addition, freshly isolated epider
mal keratinocytes were used to study integrin expression in vitro. Exp
ression of alpha v beta 6 integrin appeared relatively late during muc
osal and dermal wound healing. Maximal expression was seen in 7-day-ol
d wounds in which epithelial sheets had fused and granulation tissue w
as present. Fibronectin and tenascin, both possible ligands for alpha
v beta 6 integrin, were found concentrated underneath the basal epithe
lial cells expressing this receptor, and the maximal expression of ten
ascin coincided with that of alpha v beta 6 integrin. Freshly isolated
epidermal keratinocytes did not stain for alpha v beta 6 integrin but
began to express this integrin after subculturing. Our results sugges
t that the expression of alpha v beta 6 integrin, a putative binding i
ntegrin for fibronectin and tenascin, is induced in keratinocytes when
epithelial sheets fuse during wound healing.