ovalbumin and Hepatitis

ImmTOR biodegradable nanoparticles encapsulating rapamycin have been shown to induce a durable tolerogenic immune response to co-administered biologics and gene therapy vectors. Prior mechanism of action studies have demonstrated selective biodistribution of ImmTOR to the spleen and liver following intravenous (IV) administration. In the spleen, ImmTOR has been shown to induce tolerogenic dendritic cells and antigen-specific regulatory T cells and inhibit antigen-specific B cell activation. Splenectomy of mice resulted in partial but incomplete abrogation of the tolerogenic immune response induced by ImmTOR. Here we investigated the ability of ImmTOR to enhance the tolerogenic environment in the liver. All the major resident populations of liver cells, including liver sinusoidal endothelial cells (LSECs), Kupffer cells (KC), stellate cells (SC), and hepatocytes, actively took up fluorescent-labeled ImmTOR particles, which resulted in downregulation of MHC class II and co-stimulatory molecules and upregulation of the PD-L1 checkpoint molecule. The LSEC, known to play an important role in hepatic tolerance induction, emerged as a key target cell for ImmTOR. LSEC isolated from ImmTOR treated mice inhibited antigen-specific activation of ovalbumin-specific OT-II T cells. The tolerogenic environment led to a multi-pronged modulation of hepatic T cell populations, resulting in an increase in T cells with a regulatory phenotype, upregulation of PD-1 on CD4

Topics: Animals; B-Lymphocytes; B7-H1 Antigen; CD8-Positive T-Lymphocytes; Cells, Cultured; CTLA-4 Antigen; Dendritic Cells; Endothelial Cells; Female; Hepatic Stellate Cells; Hepatitis; Hepatocytes; Histocompatibility Antigens Class II; Immune Tolerance; Kupffer Cells; Liver; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Nanoparticles; Ovalbumin; Polyesters; Programmed Cell Death 1 Receptor; Sirolimus; T-Lymphocytes, Regulatory

The cause of most hypertensive disease is unclear, but inflammation appears critical in disease progression. However, how elevated blood pressure initiates inflammation is unknown, as are the effects of high blood pressure on innate and adaptive immune responses. We now report that hypertensive mice have increased T cell responses to antigenic challenge and develop more severe T cell-mediated immunopathology. A root cause for this is hypertension-induced erythrocyte adenosine 5'-triphosphate (ATP) release, leading to an increase in plasma ATP levels, which begins soon after the onset of hypertension and stimulates P2X7 receptors on antigen-presenting cells (APCs), increasing APC expression of CD86. Hydrolyzing ATP or blocking the P2X7 receptor eliminated hypertension-induced T cell hyperactivation. In addition, pharmacologic or genetic blockade of P2X7 receptor activity suppressed the progression of hypertension. Consistent with the results in mice, we also found that untreated human hypertensive patients have significantly elevated plasma ATP levels compared with treated hypertensive patients or normotensive controls. Thus, a hypertension-induced increase in extracellular ATP triggers augmented APC and T cell function and contributes to the immune-mediated pathologic changes associated with hypertensive disease.

Topics: Adenosine Triphosphate; Adult; Aged; Animals; Antigens; B7-2 Antigen; Dendritic Cells; Diabetes Mellitus, Type 1; Female; Hepatitis; Humans; Hypertension; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Ovalbumin; Receptors, Purinergic P2X7; T-Lymphocytes

Primary biliary cirrhosis (PBC) is a progressive autoimmune liver disease with a long natural history. The pathogenesis of PBC is thought to be orchestrated by Th1 and/or Th17. In this study, we investigated the role of CD4

Topics: Animals; Autoimmune Diseases; Cholangitis; Dependovirus; Disease Models, Animal; Fatty Acids, Monounsaturated; Female; Fibrosis; Hepatitis; Interferon-gamma; Interleukin-4; Interleukins; Liver; Mice, Inbred C57BL; Ovalbumin; Precision Medicine; Th1 Cells

Autoimmune liver diseases predominantly affect women. In this study, we aimed to elucidate how sex affects autoimmune hepatic inflammation. Acute experimental cholangitis was induced by adoptive transfer of OVA-specific CD8(+) T cells into mice, which express the cognate Ag on cholangiocytes. In contrast to previous mouse models of cholangitis, this model displayed a strong sexual dimorphism: female mice developed marked cholangitis, whereas male mice were resistant to cholangitis induction. The recruitment of endogenous CD4(+) T cells, but not transferred CD8(+) T cells into female livers was strongly increased. These cells expressed higher amounts of the proinflammatory cytokine IL-17, which was at least in part responsible for the liver inflammation observed. The recruitment of endogenous CD4(+) T cells was associated with increased expression of the chemokines CXCL-9 and CXCL-10 in female livers. The sex-specific factor responsible for the observed differences was found to be testosterone: male mice could be rendered susceptible to liver inflammation by castration, and testosterone treatment was sufficient to completely suppress liver inflammation in female mice. Accordingly, testosterone treatment of female mice significantly reduced the expression of IL-17A, CXCL-9, and CXCL-10 within the liver. Serum testosterone levels of untreated mice negatively correlated with the IL-17, CXCL-9, and CXCL-10 expression in the liver, further supporting a role for testosterone in hepatic immune homeostasis. In conclusion, testosterone was found to be the major determinant of the observed sexual dimorphism. Further study into the role of testosterone for liver inflammation could lead to novel treatment targets in human autoimmune liver diseases.

Topics: Acute Disease; Adoptive Transfer; Androgens; Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Chemokine CXCL10; Chemokine CXCL9; Cholangitis; Disease Models, Animal; Down-Regulation; Female; Flow Cytometry; Hepatitis; Interleukin-17; Liver; Male; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Ovalbumin; Peptide Fragments; Reverse Transcriptase Polymerase Chain Reaction; Sex Factors; Testosterone

The liver has the ability to prime immune responses against neo antigens provided upon infections. However, T cell immunity in liver is uniquely modulated by the complex tolerogenic property of this organ that has to also cope with foreign agents such as endotoxins or food antigens. In this respect, the nature of intrahepatic T cell responses remains to be fully characterized. To gain deeper insight into the mechanisms that regulate the CD8+ T cell responses in the liver, we established a novel OVA_X_CreER(T2) mouse model. Upon tamoxifen administration OVA antigen expression is observed in a fraction of hepatocytes, resulting in a mosaic expression pattern. To elucidate the cross-talk of CD8+ T cells with antigen-expressing hepatocytes, we adoptively transferred K(b)/OVA257-264-specific OT-I T cells to OVA_X_CreER(T2) mice or generated triple transgenic OVA_X CreER(T2)_X_OT-I mice. OT-I T cells become activated in OVA_X_CreER(T2) mice and induce an acute and transient hepatitis accompanied by liver damage. In OVA_X_CreER(T2)_X_OT-I mice, OVA induction triggers an OT-I T cell mediated, fulminant hepatitis resulting in 50% mortality. Surviving mice manifest a long lasting hepatitis, and recover after 9 weeks. In these experimental settings, recovery from hepatitis correlates with a complete loss of OVA expression indicating efficient clearance of the antigen-expressing hepatocytes. Moreover, a relapse of hepatitis can be induced upon re-induction of cured OVA_X_CreER(T2)_X_OT-I mice indicating absence of tolerogenic mechanisms. This pathogen-free, conditional mouse model has the advantage of tamoxifen inducible tissue specific antigen expression that reflects the heterogeneity of viral antigen expression and enables the study of intrahepatic immune responses to both de novo and persistent antigen. It allows following the course of intrahepatic immune responses: initiation, the acute phase and antigen clearance.

Topics: Animals; Antigens; CD8-Positive T-Lymphocytes; Disease Models, Animal; Female; Hepatitis; Hepatocytes; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Models, Immunological; Ovalbumin; Tamoxifen

V-set and Ig domain-containing 4 (VSIG4, CRIg, or Z39Ig), a newly identified B7-related cosignaling molecule, is a complement receptor and a coinhibitory ligand that negatively regulates T-cell immunity. Despite its exclusive expression on liver Kupffer cells (KCs) that play key roles in liver tolerance, the physiological role of VSIG4 in liver tolerance remains undefined. Mice lacking VSIG4 had poor survival rates and severe liver pathology in a concanavalin A (ConA)-induced hepatitis (CIH) model, which could be prevented by adoptive transfer of VSIG4(+) KCs. The absence of VSIG4 rendered endogenous liver T- and natural killer T (NKT)-cells more responsive to antigen-specific stimulation and impaired tolerance induction in those cells against their cognate antigens. T-cell costimulation with VSIG4.Ig suppressed Th1-, Th2-, and Th17-type cytokine production and arrested the cell cycle at the G(0) /G(1) phase but did not induce apoptosis in vitro. VSIG4-mediated tolerance induction and cell-cycle arrest were further supported by down-regulation of G(1) phase-specific Cdk2, Cdk4, and Cdk6, and up-regulation of tolerance-inducing p27(KIP-1) in VSIG4.Ig-stimulated T-cells. Administration of soluble VSIG4.Ig to wildtype mice prevented CIH development and prolonged the survival of mice with established CIH.. Collectively, our results suggest that VSIG4(+) KCs play a critical role in the induction and maintenance of liver T- and NKT-cell tolerance, and that modulation of the VSIG4 pathway using a VSIG4.Ig fusion protein may provide useful immunological therapies against immune-mediated liver injury including autoimmune hepatitis.

Topics: Animals; Cell Proliferation; Cells, Cultured; Chemical and Drug Induced Liver Injury; Coculture Techniques; Concanavalin A; Cytokines; Galactosylceramides; Hepatitis; Immune Tolerance; Immunoglobulin G; Kupffer Cells; Liver; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Ovalbumin; Receptors, Complement; Signal Transduction; T-Lymphocytes

Topics: Acute Disease; Animals; Autoantibodies; Chronic Disease; Erythrocytes; Graft vs Host Disease; Hemagglutination; Hepatitis; Hypersensitivity, Delayed; Immunity, Cellular; Immunoglobulins; Jaundice; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Muscle, Smooth; Ovalbumin; Reoviridae Infections; Sheep; Time Factors