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 acute rejection in rats. METHODS: Allogeneic (SD rat to LEW rat) whole and 50 % partial liver transplantation were performed. DCs from liver grafts 0 hr and 4 days after transplantation were isolated and propagated in the presence of GM-CSF in vitro. Morphological characteristics of DCs propagated for 4 days and 10 days were observed by electron microscopy. Phenotypical features of DCs propagated for 10 days were analyzed by flow cytometry. Expression of IL-12 protein and IL-12 receptor mRNA in DCs propagated for 10 days was also measured by Western blotting and semiquantitative RT-PCR, respectively. Histological grading of rejection were determined. RESULTS: Allogeneic whole liver grafts showed no features of rejection at day 4 after transplantation. In contrast, allogeneic partial liver grafts demonstrated moderate to severe rejection at day 4 after transplantation. DCs derived from allogeneic partial liver graft 4 days after transplantation exhibited typical morphological characteristics of DC after 4 days' culture in the presence of GM-CSF. DCs from allogeneic whole liver graft 0 hr and 4 days after transplantation did not exhibit typical morphological characteristics of DC until after 10 days' culture in the presence of GM-CSF. After 10 days' propagation in vitro, DCs derived from allogeneic whole liver graft exhibited features of immature DC, with absence of CD40, CD80 and CD86 surface expression, and low levels of IL-12 proteins (IL-12 p35 and IL-12 p40) and IL-12 receptor (IL-12Rbeta(1) and IL-12Rbeta(2)) mRNA, whereas DCs from allogeneic partial liver graft 4 days after transplantation displayed 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-12Rbeta(1) and IL-12Rbeta(2)) mRNA than those of DCs both from partial liver graft 0 hr and whole liver graft 4 days after transplantation (P<0.001) was observed. CONCLUSION: DCs derived from allogeneic partial liver graft undergoing acute rejection display features of mature DC.