title: Liver sinusoidal lining cells express class II major histocompatibility antigens but are poor stimulators of fresh allogeneic T lymphocytes.
abstract: Guinea pig liver sinusoidal lining cells (LSLC), a mixture of Kupffer cells (KC) and sinusoidal endothelial cells (EC), were examined for their capacity to function as antigen-presenting cells (APC). LSLC were extremely poor stimulators of freshly isolated allogeneic T lymphocytes even though a large number of them expressed class II major histocompatibility complex (MHC) antigens (Ia). This deficiency could not be explained by a lack of soluble factor production by LSLC, because an interleukin 1-containing macrophage (M phi) supernatant could not restore the capacity of LSLC to stimulate allogeneic T cells. Moreover, LSLC were able to promote mitogen-induced proliferation of accessory cell-depleted T lymphocytes. No evidence of suppression was apparent in experiments in which LSLC were added to cultures of T cells stimulated by allogeneic peritoneal exudate M phi (PEM). The Ia expressed by LSLC was functional because they were able to stimulate an alloreactive T cell line. When LSLC were mixed and co-cultured with either PEM syngeneic to the responding lymphocytes or Ia-negative fibroblasts, the allostimulatory ability of LSLC was greatly augmented. In contrast, the addition of mitogen-activated T cell supernatants had only a minimal effect on the capacity of LSLC to stimulate allogeneic T cells. The data suggest that LSLC lack a biologic property that is necessary for recognition of class II MHC determinants by fresh but not primed allogeneic T cells and that is not required to support T cell activation induced by nonspecific mitogenic lectins. These findings may be important in understanding the reason that antigen introduced into the portal blood appears not to initiate an immune response.
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000502:physiology; D006168:Guinea Pigs; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D007375:Interleukin-1 / Q000276:immunology; D007728:Kupffer Cells / Q000276:immunology; D008099:Liver / Q000166:cytology / Q000276:immunology*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1