Regulation of ICAM-1 expression and function in human dermal fibroblasts by IL-4

ICAM-1 is found on the surface of many hematopoietic and nonhematopoietic cells and can function as an adhesive ligand for the integrin, leukocyte function-associated molecule-1 (LFA-1, CD11a/CD18). ICAM-1/leukocyte function-associated molecule-1 interaction has been shown to be of importance in many immune-mediated cell-cell adhesion reactions. In vitro, unstimulated human fibroblast cell cultures express low levels of ICAM-1. Using ELISA, cytofluorography, electron microscopy, Northern analysis, and an in vitro cell adherence assay, we demonstrate that treatment of human dermal fibroblasts with the cytokine IL-4 leads to an increase in cell surface ICAM-1 expression that is under transcriptional control as well as increased fibroblast adhesion to LFA-1-bearing T lymphocytes. The kinetics of increased ICAM-1 expression induced by IL-4 paralleled the increase in ICAM-1-dependent T lymphocyte adhesion. The increase in T cell adhesion was determined to be due to the effects of IL-4 on the fibroblasts and not the adhering T cells. Treatment of fibroblasts with IL-4 also resulted in enhanced binding of human rhinovirus, a recently reported additional ligand for ICAM-1. Virus binding was IL-4 dose dependent and could be inhibited with mAb to ICAM-1. Both the expression of ICAM-1 and the ICAM-1-dependent increase in T lymphocyte adhesion that was induced by IL-4 could be inhibited by preexposure of the fibroblasts to either IL-1 or IL-6, suggesting that multiple cytokines can have both positive and negative effects on human fibroblast ICAM-1 expression and function.