ANTIGEN-PRESENTING FUNCTION AND B7 EXPRESSION OF MURINE SINUSOIDAL ENDOTHELIAL-CELLS AND KUPFFER CELLS

Background & Aims: Inflammatory liver disease as well as rejection of liver allografts are thought to be mediated by resident antigen-presen ting cells in the liver. At the same time, in vivo antigen presentatio n in the liver appears to be a more tolerogenic than systemic antigen challenge. The aim of this study was to show and characterize the anti gen-presenting capability of sinusoidal endothelial cells and Kupffer cells. Methods: Purified murine sinusoidal endothelial cells and Kupff er cells were studied for their ability to serve as accessory cells an d antigen-presenting cells by proliferation assays. They were also stu died for their expression of interleukin 1 and the B7 costimulatory mo lecules by Northern blotting, polymerase chain reaction, and flow cyto metry. Results: Both cell types expressed interleukin 1 messenger RNA and could serve equally well as accessory and antigen-presenting cells . B7-2 messenger RNA and surface expression on sinusoidal endothelial cells and on Kupffer cells was shown. Antibodies to the B7 molecules i nhibited antigen presentation. Addition of interleukin 10 as a regulat ory cytokine secreted by Kupffer cells was suppressive. Conclusions: S inusoidal endothelial cells carry functional B7-2 molecules and can se rve as effective antigen-presenting cells. However, antigen presentati on by sinusoidal endothelial cells may be locally down-regulated by in terleukin 10.