IFN-GAMMA MODULATES CD1D SURFACE EXPRESSION ON INTESTINAL EPITHELIA

In vivo, epithelial cells that line the intestine are intimately assoc iated with lymphocytes, termed intestinal intraepithelial lymphocytes (iIEL). A putative ligand for iIEL on intestinal epithelial cells is C D1d, and recent studies demonstrate a surface form of this molecule ex ists on intestinal epithelia. At present, it is not known whether CD1d expression is regulated by cytokines in the intestinal microenvironme nt. Thus we examined the impact of relevant cytokines on CD1d at the l evel of mRNA and cell surface expression. Using a sensitive whole cell enzyme-linked immunosorbent assay, we assessed the impact of relevant cytokines on CD1d expression on intestinal epithelial cell lines. We were readily able to detect CD1d on the surface of T84 cells, a cryptl ike intestinal epithelial cell line. Epithelial cell exposure to human recombinant interferon-gamma (IFN-gamma) resulted in increased CD1d e xpression in a dose- and time-dependent manner. Polymerase chain react ion amplification of CD1d cDNA revealed a time-dependent induction aft er exposure to IFN-gamma. This IFN-gamma effect on CD1d expression was cytokine specific and was evident with epithelial cell lines other th an T84, including Caco-2 and HT-29 cells. Finally, we were not able to detect significant surface expression of CD1a, CD1b, or CD1c on intes tinal epithelial cell lines in the presence or absence of relevant cyt okines. These results indicate that CD1d cell surface protein and cell ular mRNA, like other major histocompatibility complex-related molecul es, is cytokine regulated in intestinal epithelial cell lines.