Functional changes of dendritic cells derived from allogeneic partial liver graft undergoing acute rejection in rats

AIM:To investigate functional change of dendritic cells(DCs)derived from allogeneic partial liver graft undergoing acuterejection in rats.METHODS:Allogeneic(SD rat to LEW rat)whole and 50%partial liver transplantation were performed.DCs from livergrafts 0 hr and 4 days after transplantation were isolated andpropagated in the presence of GM-CSF in vitro.Morphologicalcharacteristics of DCs propagated for 4 days and 10 dayswere observed by electron microscopy.Phenotypical featuresof DCs propagated for 10 days were analyzed by flowcytometry.Expression of IL-12 protein and IL-12 receptormRNA in DCs propagated for 10 days was also measured byWestern blotting and semiquantitative RT-PCR,respectively.Histological grading of rejection were determined.RESULTS:Allogeneic whole liver grafts showed no featuresof rejection at day 4 after transplantation.In contrast,allogeneic partial liver grafts demonstrated moderate tosevere rejection at day 4 after transplantation.DCs derivedfrom allogeneic partial liver graft 4 days after transplantationexhibited typical morphological characteristics of DC after 4days’culture in the presence of GM-CSF.DCs from allogeneicwhole liver graft 0 hr and 4 days after transplantation didnot exhibit typical morphological characteristics of DC untilafter 10 days’ culture in the presence of GM-CSF.After 10days’propagation in vitro,DCs derived from allogeneic wholeliver graft exhibited features of immature DC,with absenceof CD40,CD80 and CD86 surface expression,and low levelsof IL-12 proteins(IL-12 p35 and IL-12 p40)and IL-12receptor(IL-12Rβ1and IL-12Rβ2)mRNA,whereas DCs fromallogeneic partial liver graft 4 days after transplantationdisplayed features of mature DC,with high levels of CD40,CD80 and CD86 surface expression,and as a consequence,higher expression of IL-12 proteins(IL-12 p35 and IL-12 p40)and IL-12 receptors(IL-12Rβ1and IL-12Rβ2)mRNA thanthose of DCs both from partial liver graft 0 hr and whole livergraft 4 days after transplantation(P<0.001)was observed.CONCLUSION:DCs derived from allogeneic partial liver graftundergoing acute rejection display features of mature DC.