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Updated: Aug 8, 2026

Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production
Published on: March 2, 2014
Interferon-gamma-induced HLA-DR, but not ICAM-1, expression of human keratinocytes is down-regulated by calmodulin
A Saitoh1, A Osada, Y Kitajima
1Department of Dermatology, Yamanashi Medical University, Japan.
Abstract:
Interferon-gamma (IFN-gamma) has been shown to induce or enhance the expression of MHC class II and intercellular adhesion molecule-1 (ICAM-1) in a variety of human and murine cell types, including epidermal keratinocytes (KC). However, the expression of MHC class II and ICAM-1 molecules induced by IFN-gamma is not necessarily coordinated. We investigated the inhibitory effects of the calmodulin antagonist, W-7, and its chlorine deficient inactive analogue, W-5, on the expression of MHC class II (HLA-DR) and ICAM-1 by human KC incubated with IFN-gamma. We found that the IFN-gamma-induced expression of HLA-DR was reproducibly and dose-dependently inhibited by W-7. However, the expression of ICAM-1 was highly resistant to the inhibitory effects of W-7. Neither HLA-DR nor ICAM-1 expression was affected by W-5. These data suggest that the IFN-gamma-induced HLA-DR, but not ICAM-1, expression is mediated, if not exclusively, by calmodulin in human KC.
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