Plasma transaminase levels were measured 12 hr after injection of Con A (a,b). (XLP).2 Patients with XLP disease are highly susceptible to the EpsteinCBarr virus infection and suffer from infectious mononucleosis, malignant lymphoma and hypergammaglobulinaemia or hypogammaglobulinaemia. This SAP-mediated signal is essential for the development of NKT cells (i.e. unconventional CD1d-restricted T cells with invariant V14 T-cell receptors).3 These V14 NKT cells recognize glycolipid antigens on CD1d molecules, such as -galactosylceramide (-GalCer) derived from a marine sponge or endogenous isoglobotrihexosyl ceramide, and secrete massive amounts of interleukin (IL)-4 and interferon- (IFN-).4,5 Concanavalin A (Con A)-induced hepatitis is a murine experimental model of autoimmune hepatitis. Systemic injection of the plant lectin causes haemagglutination; activation of lymphocytes; secretion of cytokines such as tumour necrosis factor- (TNF-), IL-6, IFN- and IL-4; and subsequent hepatocyte injury.6 Severe combined immunodeficiency mice and athymic mice are less sensitive to Con A-induced hepatitis, indicating that T cells are involved in hepatitis. This phenomenon is also known to be dependent on the FasCFas ligand (FasL) axis and V14 NKT cells.7C9 Several studies have reported that molecules involved in Con A-induced hepatitis are P-selectin, LIGHT (homologous to lymphotoxin, exhibits inducible expression and competes with HSV glycoprotein D for herpes virus entry mediator, a receptor expressed by T lymphocytes), osteopontin, IL-4, IFN- and CD1d. 8C14 The Fas antigen is a member of the TNF superfamily and mediates signals that induce apoptotic cell death. The MRL/Mp-(MRL/lpr) strain, in which the gene is disrupted by the insertion of a retroposon, is a lupus-prone strain.15,16 MRL/lpr mice show severe lymphadenopathy and splenomegaly as a result of the abnormal expansion of T cells, CD4? CD8? B220+ Thy12+ T cells. We previously reported new mutant mice found among the MRL/lpr PDE-9 inhibitor mice and revealed that SAP deficiency regresses the autoimmune phenotypes in the mutant mice MRL/Mp-(MRL/lpr/rpl).17 It was reported that MRL/lpr mice are less sensitive to Con A-induced hepatitis.7 Furthermore, SAP-deficient mice were thought to be less sensitive to Con A-induced hepatitis because they lack V14 NKT cells.3 Here, we report that MRL/lpr/rpl mice are sensitive to Con A-induced hepatitis and attempted to shed light on the mechanisms underlying this paradoxical Con A-induced hepatitis in MRL/lpr/rpl mice, which is independent of Fas and V14 NKT cells. Materials and methods Mice, cells and reagents MRL mice were bred under specific pathogen-free conditions in Tohoku University. MRL/+ and MRL/lpr mice Rabbit Polyclonal to CXCR4 were purchased from Charles River Japan (Tokyo, Japan). MRL/lpr/rpl mice have previously been described.17 The MRL/+/rpl mice were generated by crossing the MRL/+ mice with the MRL/lpr/rpl mice and by subsequent intercrossing of the resulting PDE-9 inhibitor heterozygous F1 mice. The F2 mice were genotyped using the following primer sets: 5-GAGAAGCTCTTACTCGGTA and PDE-9 inhibitor 5-CCACTACCACGAGATATACT with loci. In all animal experiments, we adhered to the Tohoku University guidelines for animal experiments. Hybridoma cells for PDE-9 inhibitor anti-CD4 (GK15) or anti-CD8 (53-672) monoclonal antibodies (mAbs) were provided by Tohoku University, Institute of Development, Aging and Cancer, Cell Resource Center for Biomedical Research. Antibody to asialo GM1 and antibody to Con A were purchased from Wako Pure Chemical Industries (Osaka, Japan). -GalCer was provided by KIRIN brewery (Gunma, Japan). The other mAbs were purchased from BD Bioscience (Franklin Lakes, NJ). Con A-induced hepatitis We used five mice per group for all Con A-induced hepatitis experiments. Con A was dissolved in phosphate-buffered saline (PBS) and 200 l of the solution was injected intravenously into the tail vein of MRL mice. Plasma glutamate oxalate transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels were monitored 12 hr after the injection using a Fuji Drichem 3500v (Fuji film Co., Tokyo, Japan) with slides of GOT/AST-PIII and GPT/ALT-PIII, according to the manufacturers instructions. CD4+ or CD8+ T cells, or NK cells, were depleted using monoclonal anti-CD4 or anti-CD8 or anti-asialo GM1, respectively, 3, 2 and 1 day before injection of Con A. The depletion efficiency was confirmed in the peripheral blood using a FACSCalbur flow.
