Expression of MHC antigens by intestinal epithelial cells. Effect of transforming growth factor-beta 2 (TGF-beta 2).

The effect of interferon-gamma (IFN-gamma) and TGF-beta 2 on expression of MHC antigens by the human intestinal epithelial cell line HT-29 was examined by immunohistochemistry and flow cytometry. Untreated HT-29 cells constitutively expressed HLA-ABC but little HLA-DR. Expression of both molecules was increased by IFN-gamma (100 U/ml, 24 h). TGF-beta 2 at concentrations > or = 0.5 ng/ml given before or simultaneously with IFN-gamma, inhibited the IFN-induced expression of HLA-DR. Small increases in HLA-ABC expression by IFN-gamma were further increased by pretreatment with TGF-beta 2, while a strong induction of HLA-ABC was inhibited by the TGF-beta 2 pretreatment. Our results suggest that the inhibitory action of the TGF-beta 2 on both HLA-ABC and HLA-DR correlates with the degree of induction following IFN-gamma treatment. Since TGF-beta 2 is present in milk and is produced by gut epithelial cells, one of its possible functions may be to regulate expression of HLA antigens in the neonatal intestine and/or diseased intestine.