Oral and skin keratinocytes are stimulated to secrete monocyte chemoattractant protein-1 by tumour necrosis factor-α and interferon-γ

Monocyte chemoattractant protein-1 (MCP-1) is a member of the CC subfamily of chemokines. It is chemoattractant for monocytes, activated memory T cells and dendritic cells. We studied MCP-1 mRNA and protein production in cultured human oral keratinocytes (OK) and skin keratinocytes (SK). MCP-1 production was undetectable in resting keratinocytes. However, stimulation with tumour necrosis factor-alpha (TNF-alpha) or interferon-gamma (IFN-gamma) induced MCP-1 mRNA and protein synthesis in both cell types. Together, TNF-alpha and IFN-gamma acted synergistically to increase MCP-1 production. In each case MCP-1 production was greater for SK than OK. The kinetics of IFN-gamma-induced MCP-1 production were similar for both cell types, peaking around 72 h. In contrast, TNF-alpha induced a more rapid increase in MCP-1 production by SK than OK, peak production occurring after 24 and 72 h, respectively. IL-1 alpha and IL-4 did not induce MCP-1 production. However, in combination with IFN-gamma, they induced a small extra increase in MCP-1 production in SK but not OK.