Spleen and Liver Dendritic Cells Differ in their Tolerogenic and Cytokine Induction Potential

Dendritic cells (DCs) play an important role in induction of cellular immune responses. It seems that DCs that reside in different organs may be distinct in their ability to  induce immune responses. This study was done to address the differences between spleen and liver DCs in induction of immune response and/or tolerance. CD11c+  DCs were separated from the liver and spleen of C57BL/6 mice and pulsed with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55. 6×105 MOG35-55 pulsed spleen or liver DCs were injected in foot pad of different groups of mice. Control groups received unpulsed DCs. After 5 days, the mononuclear cells (MNCs) of the regional lymph nodes were isolated from immunized mice for cytokine assays and lymphocyte transformation test. To study the immunologic or tolerogenic effects of DCs, three weeks after immunization of mice with MOG  pulsed liver or spleen DCs, experimental autoimmune encephalomyelitis (EAE)  was induced in DC-immunized mice by injection of MOG  along with complete Freund’s adjuvant. Our  results showed that spleen DCs were more potent  in stimulating lymph  node  T  cells as  illustrated in  lymphocyte transformation  test.  Moreover  IL-10 production was higher in mice immunized with liver DCs compared with those immunized with splenic DCs (p=0.017). However, no significant difference in IFN-γ  production  was observed  between  two  groups.  We also found  that  liver DCs+MOG  immunized mice displayed a significantly delayed disease onset compared with spleen DCs+MOG immunized mice and the control groups. The disease score was also milder in liver DCs immunized mice compared with other groups. It seems that the higher IL-10 production induced by the liver DCs may be one of the main factors in down regulation of immune responses in this organ. It can be concluded also that the liver DCs may inhibit the progress of EAE by shifting the cytokines profile.