• hepatocellular carcinoma
• immunotherapy
• inflammation
• tumor immunology
• tumor microenvironment

• Immunity, Innate
• Virion
• Viruses/genetics

• R01 AI148144 NIAID NIH HHS
• F32 AI161866 NIAID NIH HHS
• F32 AI140567 NIAID NIH HHS
• F30 AI160828 NIAID NIH HHS
• T32 AI007405 NIAID NIH HHS
• National Institute of Allergy and Infectious Diseases

• Atlas
• Immune-mediated liver disease
• Naive T cells
• Primary Sclerosing Cholangitis
• Single-cell sequencing
• T cells
• T(H)17 cells
• Tissue residency

• Cholangitis, Sclerosing/enzymology
• Cholangitis, Sclerosing/physiopathology
• Hepatocytes/physiology
• Humans
• Liver/pathology
• Liver/physiopathology
• T-Lymphocytes/physiology
• Exome Sequencing/methods

• Antibody
• Chronic hepatitis B virus
• Hepatitis B
• Immune response
• Interleukin-21
• T follicular helper cells

• Activation
• CD4+
• CD8+
• Cytokine
• Exhaustion
• Human
• Liver
• T lymphocyte
• Tolerance

Liver allograft rejection remains a significant cause of morbidity and graft failure in liver transplant recipients. Rejection is caused by the recognition of non-self donor alloantigens by recipient T-cells. Antigen recognition results in proliferation and activation of T-cells in lymphoid tissue before migration to the allograft. Activated T-cells have a variety of effector mechanisms including direct T-cell mediated damage to bile ducts, endothelium and hepatocytes and indirect effects through cytokine production and recruitment of tissue-destructive inflammatory cells. These effects explain the histological appearances of typical acute T-cell mediated rejection. In addition, donor specific antibodies, most typically against HLA antigens, may give rise to antibody-mediated rejection causing damage to the allograft primarily through endothelial injury. However, as an immune-privileged site there are several mechanisms in the liver capable of overcoming rejection and promoting tolerance to the graft, particularly in the context of recruitment of regulatory T-cells and promotors of an immunosuppressive environment. Indeed, around 20% of transplant recipients can be successfully weaned from immunosuppression. Hence, the host immunological response to the liver allograft is best regarded as a balance between rejection-promoting and tolerance-promoting factors. Understanding this balance provides insight into potential mechanisms for novel anti-rejection therapies.

• dendritic cells
• immunomodulatory
• regulatory T cell
• tolerance
• transplantation

Liver transplantation (LT) is currently the only effective treatment option for end-stage liver disease. The importance of animal models in transplantation is widely recognized among researchers. Because of the well-characterized mouse genome and the greater diversity and availability of both genetically modified animals and research reagents, mouse orthotopic LT (MOLT) has become an ideal model for the investigation of liver biology, tissue injury, regulation of alloimmunity and tolerance induction, and the pathogenesis of specific liver diseases. However, due to its complicated and technically demanding procedure, the model has merely been used by only a few research groups in the world for years. For a new learner, training lasting at least a couple of months or even years is required. Most of the investigators have emphasized the importance of elaborate techniques and dedicated instruments in establishing a MOLT model, but some details are often neglected. The nontechnical details are also significant, especially for researchers who have little experience in mouse microsurgery. Here, we review and summarize the crucial technical and nontechnical details in establishing the model of MOLT based on scientific articles and our experience in six aspects: animal selection, anesthesia, perioperative management, organ procurement, back-table preparation, and implantation surgery. We aim to enable research groups to shorten the learning curve and implement the mouse LT procedure with high technical success.

• Mouse orthotopic liver transplantation
• Animal selection
• Anesthesia
• Perioperative management
• Organ procurement
• Back-table preparation
• Implantation surgery

• Animals
• Disease Models, Animal
• Humans
• Liver Diseases
• Liver Transplantation
• Mice
• Microsurgery

The liver is an immunologically tolerant organ that is uniquely equipped to limit hypersensitivity to food-derived antigens and bacterial products through the portal vein and can feasibly accept liver allografts. The adaptive immune response is a major branch of the immune system that induces organ/tissue-localized and systematic responses against pathogens and tumors while promoting self-tolerance. Persistent infection of the liver with a virus or other pathogen typically results in tolerance, which is a key feature of the liver. The liver's immunosuppressive microenvironment means that hepatic adaptive immune cells become readily tolerogenic, promoting the death of effector cells and the “education” of regulatory cells. The above mechanisms may result in the clonal deletion, exhaustion, or inhibition of peripheral T cells, which are key players in the adaptive immune response. These tolerance mechanisms are believed to be responsible for almost all liver diseases. However, optimal protective adaptive immune responses may be achieved through checkpoint immunotherapy and the modulation of hepatic innate immune cells in the host. In this review, we focus on the mechanisms involved in hepatic adaptive immune tolerance, the liver diseases caused thereby, and the therapeutic strategies needed to overcome this tolerance.

• T cell dysfunction
• immune regulation
• innate cell dysfunction
• liver diseases
• liver tolerance
• liver-draining lymph node

• T cells
• autoantibodies
• autoimmune hepatitis
• autoimmunity
• cirrhosis
• hepatocyte

• T cell priming
• cross-presentation
• endogenous antigen presentation
• hepatitis B virus
• intrahepatic lymphocytes
• liver
• tolerance

• Animals
• Antigen Presentation/immunology
• CD8-Positive T-Lymphocytes/immunology
• Cross-Priming/immunology
• Dendritic Cells/immunology
• Hepatitis B virus/immunology
• Hepatitis B, Chronic/immunology
• Histocompatibility Antigens Class I/immunology
• Liver/immunology
• Lymphocyte Activation/immunology
• Male
• Mice
• Mice, Knockout

• R01 AI079060 NIAID NIH HHS
• HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)
• Japan Agency for Medical Research and Development (AMED)
• Ministry of Education, Culture, Sports, Science and Technology (MEXT)

• Tregs
• immunosuppression
• liver transplantation
• tolerance

• Animals
• CD8-Positive T-Lymphocytes/immunology
• Female
• Immunity, Mucosal/immunology
• Immunologic Memory/immunology
• Immunologic Surveillance/immunology
• Intravital Microscopy
• Mice
• Mucous Membrane/cytology
• Mucous Membrane/immunology
• Skin/immunology

• R37 AI084913 NIAID NIH HHS
• T32 AI007313 NIAID NIH HHS
• R01 AI084913 NIAID NIH HHS
• R01 AI111671 NIAID NIH HHS
• R21 AI123600 NIAID NIH HHS

• Liver
• Stellate cell
• Vitamin A

• Acute and Chronic Liver inflammation
• Kupffer Cells
• Liver macrophages

• Humans
• Immune Tolerance/immunology
• Liver/immunology
• Liver/pathology
• Liver Transplantation/methods

• R01 DK084192 NIDDK NIH HHS
• R21 AI090468 NIAID NIH HHS

Both experimental and clinical studies have shown that the liver possesses unique tolerogenic properties. Liver allografts can be spontaneously accepted across complete major histocompatibility mismatch in some animal models. In addition, some liver transplant patients can be successfully withdrawn from immunosuppressive medications, developing ‘operational tolerance'. Multiple mechanisms have been shown to be involved in inducing and maintaining alloimmune tolerance associated with liver transplantation. Here, we focus on CD8 T-cell tolerance in this setting. We first discuss how alloreactive cytotoxic T-cell responses are generated against allografts, before reviewing how the liver parenchyma, donor passenger leucocytes and the host immune system function together to attenuate alloreactive CD8 T-cell responses to promote the long-term survival of liver transplants.

• immune cells
• ischemia-reperfusion injury
• transplant tolerance

• Antigen load
• CD4 T cell help
• CD8 T cell exhaustion
• Cytotoxic T cells
• Immunity
• Tolerance
• Viral hepatitis

• ifn-γ
• b7-h1
• immune regulation
• t effector cell
• apoptosis

• Animals
• Cytokines/immunology
• Disease Models, Animal
• Graft Rejection/immunology
• Graft Survival/immunology
• Immune Tolerance/immunology
• Immunologic Factors/metabolism
• Liver Transplantation/adverse effects
• Male
• Mesoderm/immunology
• Mesoderm/metabolism
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Mice, Transgenic
• Receptors, Interferon/immunology
• Receptors, Interferon/metabolism
• Sensitivity and Specificity
• T-Lymphocytes, Regulatory/immunology
• T-Lymphocytes, Regulatory/metabolism
• Transplantation Immunology/physiology
• Transplantation, Homologous
• Interferon gamma Receptor

• R01 DK084192 NIDDK NIH HHS
• R21 AI090468 NIAID NIH HHS
• AI090468 NIAID NIH HHS
• R01 DK058316 NIDDK NIH HHS
• DK084192 NIDDK NIH HHS

During the pre-erythrocytic asymptomatic phase of malarial infection, sporozoites develop transiently inside less than 100 hepatocytes that subsequently release thousands of merozoites. Killing of these hepatocytes by cytotoxic T cells (CTLs) confers protection to subsequent malarial infection, suggesting that this bottleneck phase in the parasite life cycle can be targeted by vaccination. During natural transmission, although some CTLs are generated in the skin draining lymph nodes, they are unable to eliminate the parasite, suggesting that the liver is important for the sporozoite to escape immune surveillance. The contribution of the organ to this process is unclear. Based on the known ability of several hepatic antigen-presenting cells (APCs) to induce primary activation of CD8 T cells and tolerance, malarial antigens presented by both infected hepatocytes and/or hepatic cross-presenting APCs should result in tolerance. However, our latest model predicts that due to the low frequency of infected hepatocytes, some T cells recognizing sporozoite epitopes with high affinity should differentiate into CTLs. In this review, we discuss two possible models to explain why CTLs generated in the liver and skin draining lymph nodes are unable to eliminate the parasite: (1) sporozoites harness the tolerogenic property of the liver; (2) CTLs are not tolerized but fail to detect infected cells due to sparse infection of hepatocytes and the very short liver stage. We propose that while malaria sporozoites might use the ability of the liver to tolerize both naive and effector cells, they have also developed strategies to decrease the probability of encounter between CTLs and infected liver cells. Thus, we predict that to achieve protection, vaccination strategies should aim to boost intrahepatic activation and/or increase the chance of encounter between sporozoite-specific CTLs and infected hepatocytes.

• Kupffer cells
• LSEC
• T cells
• dendritic cells
• hepatic stellate cells
• hepatocytes
• sporozoite
• tolerance

Malaria parasites spend a critical phase of their life cycle inside hepatocytes, in an environment with complex and distinctive immunological features. Here I will discuss how the immunological features of the liver and the adaptations of malaria parasites interact, resulting in defective CD8+ T cell immunity. These processes are explored with a focus on the mechanism by which CD4+ T cells deliver help to CD8+ T cells, and specifically through their interaction with antigen-presenting cells (APCs), resulting in “licensing” of the APCs and enhanced capacity to optimally activate CD8+ T cells. Synthesis of the available evidence supports a model in which the parasite-mediated manipulation of programmed cell death in infected hepatocytes impairs the capacity of the liver’s immune system to successfully license APCs and fully activate T cell immunity.

• CD4+ T cell help
• CD8+ T cell
• antigen-presenting cells
• hepatocyte
• immunity
• licensing
• liver
• malaria parasite

• CTL
• TCR
• cytotoxicity
• rAAV

The appearance of donor-derived lymphocytes in liver transplant patients suggests that adult livers may contain cells capable of lymphopoiesis. However, only a few published studies have addressed the lymphopoietic capacity of adult liver cells, and its kinetics and features remain unclear. Herein, we investigated the lymphopoietic capacity of adult liver mononuclear cells (MNCs) and purified liver hematopoietic progenitor cells (HPCs) in vivo. Similar to bone-marrow transplantation (BMT), transplantation of liver MNCs alone was able to rescue survival of lethally irradiated mice. In terms of kinetics, liver MNC-derived myeloid lineage cells reconstituted more slowly than those from BMT. Liver MNC-derived lymphocyte lineage cells in the blood, spleen and BM also reconstituted more slowly than BMT, but lymphocytes in the liver recovered at a similar rate. Interestingly, liver MNCs predominantly gave rise to CD3⁺CD19⁻ T cells in both irradiated WT and non-irradiated lymphocyte-deficient Rag-1^−/−Il2rg^−/− recipients. To define the lymphopoietic potential of various cell populations within liver MNCs, we transplanted purified lineage-negative (Lin⁻) liver HPCs into recipient mice. Unlike total liver MNCs, liver HPCs reconstituted T and B cells in similar frequencies to BMT. We further determined that the predominance of T cells observed after transplanting total liver MNCs likely originated from mature T cells, as purified donor liver T cells proliferated in the recipients and gave rise to CD8⁺ T cells. Thus, the capacity of donor adult liver cells to reconstitute lymphocytes in recipients derives from both HPCs and mature T cells contained in the liver MNC population.

• Animals
• CD8-Positive T-Lymphocytes/cytology
• CD8-Positive T-Lymphocytes/immunology
• Cell Proliferation
• Hematopoietic Stem Cells/cytology
• Kinetics
• Liver/cytology
• Liver/immunology
• Liver Transplantation
• Lymphopoiesis
• Mice
• Mice, Inbred C57BL
• Myeloid Cells/cytology

Immunologic memory induced by pathogenic agents or vaccinations is inextricably linked to long-lasting protection. Adequately maintained memory T and B cell pools assure a fast, effective, and specific response against re-infections. Studies of immune responses amongst residents of malaria endemic areas suggest that memory responses to Plasmodia antigens appear to be neither adequately developed nor maintained, because persons who survive episodes of childhood malaria remain vulnerable to persistent or intermittent malaria infections. By contrast, multiple exposures of humans and laboratory rodents to radiation-attenuated Plasmodia sporozoites (γ-spz) induces sterile and long-lasting protection against experimental sporozoite challenge. Protection is associated with MHC-class I-dependent CD8 T cells, the key effectors against pre-erythrocytic stage infection. We have adopted the P. berghei γ-spz mouse model to study memory CD8 T cells that are specific for antigens expressed by Pb liver-stage (LS) parasites and are found predominantly in the liver. On the basis of phenotypic and functional characteristics, we have demonstrated that liver CD8 T cells form two subsets: CD44^hiCD62L^loKLRG-1⁺CD107⁺CD127⁻CD122^loCD8 T effector/effector memory (T_E/EM) cells that are the dominant IFN-γ producers and CD44^hiCD62L^hiKLRG-1⁻CD107⁻CD127⁺CD122^hiCD8 T central memory (T_CM) cells. In this review, we discuss our observations concerning the role of CD8 T_E/EM and CD8 T_CM cells in the maintenance of protracted protective immunity against experimental malaria infection. Finally, we present a hypothesis consistent with a model whereby intrahepatic CD8 T_CM cells, that are maintained in part by LS-Ag depot and by IL-15-mediated survival and homeostatic proliferation, form a reservoir of cells ready for conscription to CD8 T_E/EM cells needed to prevent re-infections.

• CD8 T cells
• IL-15
• Plasmodium
• liver
• malaria
• memory T cells
• mouse model

The liver is an immunologically unique organ containing tolerogenic dendritic cells (DC) that maintain an immunosuppressive microenvironment. Although systemic IL-12 administration can improve responses to tumors, the effects of IL-12-based treatments on DC, in particular hepatic DC, remain incompletely understood. In this study, we demonstrate systemic IL-12 administration induces a 2–3 fold increase in conventional, but not plasmacytoid, DC subsets in the liver. Following IL-12 administration, hepatic DC became more phenotypically and functionally mature, resembling the function of splenic DC, but differed as compared to their splenic counterparts in the production of IL-12 following co-stimulation with toll-like receptor (TLR) agonists. Hepatic DCs from IL-12 treated mice acquired enhanced T cell proliferative capabilities similar to levels observed using splenic DCs. Furthermore, IL-12 administration preferentially increased hepatic T cell activation and IFNγ expression in the RENCA mouse model of renal cell carcinoma. Collectively, the data shows systemic IL-12 administration enables hepatic DCs to overcome at least some aspects of the inherently suppressive milieu of the hepatic environment that could have important implications for the design of IL-12-based immunotherapeutic strategies targeting hepatic malignancies and infections.

• Animals
• Carcinoma, Renal Cell/immunology
• Dendritic Cells/drug effects
• Dendritic Cells/immunology
• Flow Cytometry
• Interferon-gamma/metabolism
• Interleukin-12/administration & dosage
• Interleukin-12/pharmacology
• Liver/cytology
• Liver/immunology
• Lymphocyte Activation/drug effects
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Statistics, Nonparametric
• T-Lymphocytes/immunology

• Intramural NIH HHS

• liver
• animal models
• t lymphocytes and co-stimulation