Lack of interleukin 10 regulation of antigen presentation-associated molecules expressed on colonic epithelial cells

Colonic epithelial cells may behave as antigen-presenting cells. Interleukin 10 (IL-10) is known to play a major role in the intestinal immune system; however, it remains to be determined whether human intestinal epithelial cells express IL-10 receptor, and whether this cytokine modulates their expression of antigen presentation-associated molecules.

The binding of biotinylated IL-10 was studied in SW 1116, HT-29 and T84 human colonic epithelial cell lines and freshly isolated normal colonic epithelial cells. Reverse transcription-polymerase chain reaction was also performed to detect IL-10 receptor mRNA. The effect of IL-10 on antigen presentation associated molecules was assessed by flow cytometry.

Biotinylated IL-10 bound to SW 1116, HT-29, T84, and normal colonic epithelial cells. IL-10 receptor mRNA was detected in SW 1116 and normal epithelial cells. SW 1116 and HT-29 cells expressed MHC class I and ICAM-1, but not CD80, and SW 1116 constitutively expressed HLA-DR. Interferon-gamma up-regulated HLA-DR and ICAM-1 expression on both cells, whereas lipopolysaccharide increased ICAM-1 expression only on SW 1116. IL-10 failed to modulate these antigens, even after stimulation by lipopolysaccharide or interferon-gamma. Moreover, these molecules decreased IL-10 binding in both lines.

The presence of IL-10 receptor on intestinal epithelial cells suggest that IL-10 may play a role in mucosal physiology, however its effect on the immune response remains to be determined.