Higher concentrations of interferon-gamma enhances uptake and transport of dietary antigens by human intestinal cells: A study using cultured Caco-2 cells

• Published in: Journal of Nutritional Science and Vitaminology 2003, Vol.49(3), pp.179-186
• Main Authors: Koda, T. (Yamaguchi Prefectural Univ. (Japan)), Minami, H, Ogawa, T, Yamano, M, Takeda, E
• Format: Article
• Language: English
• Subjects: Antigen Presentation - immunology; antigen uptake; Antigen-Presenting Cells; ANTIGENS; Biological and medical sciences; Biological Transport - drug effects; Caco-2 Cells; CELL CULTURE; DIET; Epithelial Cells; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Humans; Immunohistochemistry; INTERFERON; interferon (IFN)-γ; Interferon-gamma - pharmacology; Intestinal Mucosa - immunology; Intestinal Mucosa - metabolism; Intestine. Mesentery; INTESTINES; ovalbumin (OVA); Ovalbumin - metabolism; Permeability - drug effects; transcellular transport; Vertebrates: digestive system
• ISSN: 0301-4800; 1881-7742
• DOI: 10.3177/jnsv.49.179

Besides functioning as a mucosal barrier and transporting nutrients, intestinal epithelial cells (IECs) also serve as antigen-presenting cells (APCs). Modification of protein antigens by proteolysis is one of the principal steps in antigen presentation to Th cells. We used a Caco-2 intestinal epithelial cell line to investigate the transepithelial transport of the dietary antigen, ovalbumin (OVA). We also examined the effects of the proinflammatory cytokine interferon-γ (IFN-γ) on the antigen transport process in Caco-2 cell layers. Caco-2 cell layers transferred both intact and degraded OVA from the mucosal to the serosal side. IFN-γ stimulated OVA transport and most of the transported OVA in such cells were degraded. We also examined OVA uptake by Caco-2 cells using immunohistochemical means. Caco-2 cells incorporated OVA in a time-dependent manner and IFN-γ significantly enhanced antigen internalization. Flow cytometry also demonstrated that IFN-γ elevated the internalization of FITC-OVA. We also determined the effects of low and high concentrations of IFN-y on mucosal permeability and internalization of FITC-OVA. Althoughh both 10 and 50ng/mL IFN-γ stimulated mucosal permeability to the same extent, more FITC-OVA was internalized by Caco-2 cells incubated with 50 than with 10ng/mL IFN-y. These results suggest that the effects of IFN-γ on mucosal permeability and the internalization of antigens by intestinal epithelial cells are brought about by different mechanisms. Therefore, higher concentrations of IFN-γ stimulate the uptake, processing, and transport of dietary antigens by IECs.