Razi Journal of Medical Sciences

    Background & Objective: Dendritic cells(DCs) play an important role in directing immune response toward TH₁(T-Helper 1) or TH₂(T-Helper 2). These cells may induce distinct cytokine patterns in different tissues. So the pattern of cytokine induction by liver and spleen DCs may differ from each other. To investigate the difference between immune responses in the liver(as a non-lymphoid organ and tolerogenic tissue) and the spleen(as a lymphoid organ and an immunogenic tissue), we analyzed the function of spleen and liver DCs in the induction of TH₁ and TH₂ immune responses.

Method: DCs were isolated from the liver and spleen of normal C57BL/6 mice by enzymatic digestion and nycodenz centrifugation gradient. Isolated DCs were pulsed with a proper concentration of myelin oligodendrocyte glycoprotein peptide(MOG35-55). About 6 × 10⁵ pulsed DCs from liver and spleen were injected to the footpad of two different groups of mice. Unpulsed DCs were injected to the control group. After 5 days, mononuclear cells(MNCs) of the poplital lymph nodes were isolated from immunized mice and cultured in the presence and absence of MOG35-55 for 96 hours. The supernatant of the cultured cells was collected and the amount of produced cytokines(IL-10: Interleukin-10 and IFN- γ : Interferon gamma ) was measured by ELISA(Enzyme-Linked Immunosorbent Assay).

Results: Our findings showed that IL-10 and IFN- γ production in mice immunized with DCs pulsed with MOG35-55 was significantly higher than the control group(p=0.004). There was no significant difference in IFN- γ production between mice immunized with liver DCs and those immunized with splenic DCs, but the amount of IL-10 production in the first group was higher than the second group(p=0.01).

Conclusion: It seems that higher IL-10 production induced by liver DCs may be one of the main factors in down regulation of immune responses in this organ.