Infusion of donor hepatic non-parenchymal cells prolongs survival of skin allografts in mice:role of microchimerism and IL-4

BACKGROUND: In the mouse skin allograft model, specific immune tolerance to the donor was induced by injection of donor hepatic non-parenchymal cells (NPCs). This markedly prolonged the survival time of the allograft. The mechanism of the induction of immune tolerance with donor hepatic NPCs is thought to be related to microchimerism and the IL-4 level. This work aimed at exploring the way of inducing immune tolerance and understanding the mechanism. METHODS: C57BL/6 (B6) mice were primed by intravenous injection of 2 X10(7) NPCs from C3H mice. Cyclophosphamide (200 mg/kg) was injected intraperitoneally 48 hours later. Eighteen days after the NPC injection, skin from C3H mice was transplanted to B6 mice and the survival of the grafts was assessed. The immune reaction of splenocytes from the treated B6 mice to donor-specific T-cells was measured by H-3-TdR incorporation. Microchimerism in the spleen was determined by flow cytometric analysis sytem (FCAS) analysis, and the serum level of IL-4 was assayed by ELISA at designed times. RESULTS: The survival time of the skin graft was markedly prolonged from 10 days to 70 days in controls. Microchimerism. in the spleen was found as early as day I post-NPC injection, then it increased steadily, and there was a positive relationship between graft survival and the quantity of microchimerism. The ELISA results showed that NPC infusion enhanced IL-4 production, especially in the mice with longer graft survival. CONCLUSION: Donor NPC infusion pre-transplant can prolong the survival of the skin graft and microchimerism and high levels of IL-4 may be involved.

The effects of tumor necrosis factor on cultured hepatocytes and non-parenchymal liver ceils in the mouse

The effects of tumor necrosis factor(TNF)on the cultured mouse hepa-tocytes and non-parenchymal liver cells were observed.It was found that therewere no significant changes of the morphological integrity and viability of thehepatocytes and the aspartate transferase level in the culture supernate after theaddition of TNF into the culture medium as compared with those of the normalcontrol,which indicates that TNF exerts no obvious cytotoxocity on the culturedmouse hepatocytes. In addition,there were also no significant changes of theabove mentioned parameters after TNF was added to the cocultures of hepato-cytes and non-parenchymal liver cells,which implies that the unactivated non-parenchymal liver cells are not involved in the TNF-related hepatocyte injury.

Immunohistochemical Aspects of Ito and Kupffer Cells in the Liver of Domesticated and Wild Ruminants

The mammalian liver is a morphologically and functionally complex organ, made up of not only of the largely predominant parenchymal cells (hepatocytes) but also non-parenchymal cells. Although there are less non-parenchymal cells than hepatocytes, they nevertheless play an important role in regulating many hepatocyte functions, as well as in the immunology of the liver. We investigated the structural aspects of the liver and the morpho-functional characteristics of Ito and Kupffer cells in two domesticated ruminant species (cattle and goat) in comparison with four wild ruminant species living in captivity in a zoo in northern Italy. The liver specimens were studied using histological, histochemical and immunohistochemical methods. The liver parenchyma was structurally normal. Immunohistochemistry was performed for desmin, glial fibrillary acidic protein (GFAP), vimentin, α-smooth muscle actin (α-SMA), collagen I, lysozyme, CD 68 and tumor necrosis factor α (TNF-α). In all the studied ruminants, Ito cells reacted with desmin and vimentin antibodies, Kupffer cells were evidenced only with lysozyme-immunopositivity, and both displayed a characteristic distribution in the hepatic lobular/acinar structure. The results obtained, not only contribute to the knowledge of ruminant wild species, but also help to define a normal structure reference for the diagnosis and treatment of liver diseases.