InVivoMAb anti-mouse IFNγ

Catalog #BE0054
Product Citations:
47
Clone:
R4-6A2
Reactivities:
Mouse

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Product Details

The R4-6A2 monoclonal antibody reacts with mouse IFNγ (interferon gamma) a 20 kDa soluble pleiotropic cytokine and the sole member of the type II class of interferons. IFNγ is primarily produced by activated lymphocytes including T, B, NK cells, and ILCs. IFNγ exerts immunoregulatory, anti-proliferative, anti-viral, and proinflammatory activities and plays an important role in activation, growth, and differentiation of T and B lymphocytes, macrophages, NK cells and other non-hematopoietic cell types. Additionally, IFNγ induces the production of cytokines, Fc receptor, and adhesion molecules and up-regulates MHC class I and II antigen expression by antigen presenting cells during an immune response. IFNγ has also been shown to modulate macrophage effector functions, influence isotype switching and induce the secretion of immunoglobulins by B cells. IFNγ signals through the IFN gamma receptor which exists as a heterodimer composed of CD119 (IFNγ receptor 1) and AF-1 (IFNγ receptor 2). The IFNγ receptor is expressed ubiquitously on almost all cell types with the exception of mature erythrocytes. The R4-6A2 antibody has been shown to neutralize both natural and recombinant IFNγ.

Specifications

Isotype Rat IgG1, κ
Recommended Isotype Control(s) InVivoMAb rat IgG1 isotype control, anti-horseradish peroxidase
Recommended Dilution Buffer InVivoPure pH 8.0 Dilution Buffer
Conjugation This product is unconjugated. Conjugation is available via our Antibody Conjugation Services.
Immunogen Partially-purified native mouse IFNγ
Reported Applications in vivo IFNγ neutralization
in vitro IFNγ neutralization
Formulation PBS, pH 8.0
Contains no stabilizers or preservatives
Endotoxin <2EU/mg (<0.002EU/μg)
Determined by LAL gel clotting assay
Purity >95%
Determined by SDS-PAGE
Sterility 0.2 µm filtration
Production Purified from cell culture supernatant in an animal-free facility
Purification Protein G
RRID AB_1107692
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.
in vivo IFNγ neutralization
Clemente-Casares, X., et al. (2016). "Expanding antigen-specific regulatory networks to treat autoimmunity" Nature 530(7591): 434-440. PubMed

Regulatory T cells hold promise as targets for therapeutic intervention in autoimmunity, but approaches capable of expanding antigen-specific regulatory T cells in vivo are currently not available. Here we show that systemic delivery of nanoparticles coated with autoimmune-disease-relevant peptides bound to major histocompatibility complex class II (pMHCII) molecules triggers the generation and expansion of antigen-specific regulatory CD4(+) T cell type 1 (TR1)-like cells in different mouse models, including mice humanized with lymphocytes from patients, leading to resolution of established autoimmune phenomena. Ten pMHCII-based nanomedicines show similar biological effects, regardless of genetic background, prevalence of the cognate T-cell population or MHC restriction. These nanomedicines promote the differentiation of disease-primed autoreactive T cells into TR1-like cells, which in turn suppress autoantigen-loaded antigen-presenting cells and drive the differentiation of cognate B cells into disease-suppressing regulatory B cells, without compromising systemic immunity. pMHCII-based nanomedicines thus represent a new class of drugs, potentially useful for treating a broad spectrum of autoimmune conditions in a disease-specific manner.

in vivo IFNγ neutralization
Deligne, C., et al. (2015). "Anti-CD20 therapy induces a memory Th1 response through the IFN-gamma/IL-12 axis and prevents protumor regulatory T-cell expansion in mice" Leukemia 29(4): 947-957. PubMed

The long-lasting clinical response by lymphoma patients to anti-CD20 therapy has been attributed to the induction of an anti-tumor adaptive immunity. We previously demonstrated that a CD4-dependent mechanism is responsible for the long-term protection of CD20(+) tumor-bearing mice by anti-CD20 treatment. Here, we compare tumor immunity in tumor-bearing animals that did or did not receive anti-CD20 treatment. Splenic CD4(+)FoxP3(+) regulatory T cells (Tregs) expanded substantially in untreated mice that exhibited then a reduced survival, whereas Tregs depletion led to long-term survival of the animals, suggesting the establishment of a Treg-dependent immunosuppressive environment after tumor injection. Strikingly, anti-CD20 therapy reversed the initial expansion of Tregs, and was accompanied by a marked increase in the number of Th1 cells, with no detectable change in Th2 and Th17 cell numbers. Interleukin-12 serum level was also increased by the anti-CD20 treatment, and activated myeloid dendritic cells producing interleukin-12 could be detected in lymph nodes of treated animals, while interferon-gamma blockade strongly reduced survival. Also, CD4(+) effector memory T cells were evidenced in surviving animals, and the transfer of CD4(+) T cells induced long-term protection. Thus, anti-CD20 therapy promotes strong anti-tumor adaptive immunity, opposes Treg expansion and inhibits tumor cells from maintaining an immunosuppressive environment.

in vivo IFNγ neutralization
Conde, P., et al. (2015). "DC-SIGN(+) Macrophages Control the Induction of Transplantation Tolerance" Immunity 42(6): 1143-1158. PubMed

Tissue effector cells of the monocyte lineage can differentiate into different cell types with specific cell function depending on their environment. The phenotype, developmental requirements, and functional mechanisms of immune protective macrophages that mediate the induction of transplantation tolerance remain elusive. Here, we demonstrate that costimulatory blockade favored accumulation of DC-SIGN-expressing macrophages that inhibited CD8(+) T cell immunity and promoted CD4(+)Foxp3(+) Treg cell expansion in numbers. Mechanistically, that simultaneous DC-SIGN engagement by fucosylated ligands and TLR4 signaling was required for production of immunoregulatory IL-10 associated with prolonged allograft survival. Deletion of DC-SIGN-expressing macrophages in vivo, interfering with their CSF1-dependent development, or preventing the DC-SIGN signaling pathway abrogated tolerance. Together, the results provide new insights into the tolerogenic effects of costimulatory blockade and identify DC-SIGN(+) suppressive macrophages as crucial mediators of immunological tolerance with the concomitant therapeutic implications in the clinic.

in vitro IFNγ neutralization
Wensveen, F. M., et al. (2015). "NK cells link obesity-induced adipose stress to inflammation and insulin resistance" Nat Immunol 16(4): 376-385. PubMed

An important cause of obesity-induced insulin resistance is chronic systemic inflammation originating in visceral adipose tissue (VAT). VAT inflammation is associated with the accumulation of proinflammatory macrophages in adipose tissue, but the immunological signals that trigger their accumulation remain unknown. We found that a phenotypically distinct population of tissue-resident natural killer (NK) cells represented a crucial link between obesity-induced adipose stress and VAT inflammation. Obesity drove the upregulation of ligands of the NK cell-activating receptor NCR1 on adipocytes; this stimulated NK cell proliferation and interferon-gamma (IFN-gamma) production, which in turn triggered the differentiation of proinflammatory macrophages and promoted insulin resistance. Deficiency of NK cells, NCR1 or IFN-gamma prevented the accumulation of proinflammatory macrophages in VAT and greatly ameliorated insulin sensitivity. Thus NK cells are key regulators of macrophage polarization and insulin resistance in response to obesity-induced adipocyte stress.

in vivo IFNγ neutralization
Walsh, K. B., et al. (2014). "Animal model of respiratory syncytial virus: CD8+ T cells cause a cytokine storm that is chemically tractable by sphingosine-1-phosphate 1 receptor agonist therapy" J Virol 88(11): 6281-6293. PubMed

The cytokine storm is an intensified, dysregulated, tissue-injurious inflammatory response driven by cytokine and immune cell components. The cytokine storm during influenza virus infection, whereby the amplified innate immune response is primarily responsible for pulmonary damage, has been well characterized. Now we describe a novel event where virus-specific T cells induce a cytokine storm. The paramyxovirus pneumonia virus of mice (PVM) is a model of human respiratory syncytial virus (hRSV). Unexpectedly, when C57BL/6 mice were infected with PVM, the innate inflammatory response was undetectable until day 5 postinfection, at which time CD8(+) T cells infiltrated into the lung, initiating a cytokine storm by their production of gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha). Administration of an immunomodulatory sphingosine-1-phosphate (S1P) receptor 1 (S1P1R) agonist significantly inhibited PVM-elicited cytokine storm by blunting the PVM-specific CD8(+) T cell response, resulting in diminished pulmonary disease and enhanced survival. IMPORTANCE: A dysregulated overly exuberant immune response, termed a “cytokine storm,” accompanies virus-induced acute respiratory diseases (VARV), is primarily responsible for the accompanying high morbidity and mortality, and can be controlled therapeutically in influenza virus infection of mice and ferrets by administration of sphingosine-1-phosphate 1 receptor (S1P1R) agonists. Here, two novel findings are recorded. First, in contrast to influenza infection, where the cytokine storm is initiated early by the innate immune system, for pneumonia virus of mice (PVM), a model of RSV, the cytokine storm is initiated late in infection by the adaptive immune response: specifically, by virus-specific CD8 T cells via their release of IFN-gamma and TNF-alpha. Blockading these cytokines with neutralizing antibodies blunts the cytokine storm and protects the host. Second, PVM infection is controlled by administration of an S1P1R agonist.

in vivo IFNγ neutralization
Hock, K., et al. (2014). "Donor CD4 T cells trigger costimulation blockade-resistant donor bone marrow rejection through bystander activation requiring IL-6" Am J Transplant 14(9): 2011-2022. PubMed

Bone marrow (BM) transplantation under costimulation blockade induces chimerism and tolerance. Cotransplantation of donor T cells (contained in substantial numbers in mobilized peripheral blood stem cells and donor lymphocyte infusions) together with donor BM paradoxically triggers rejection of donor BM through undefined mechanisms. Here, nonmyeloablatively irradiated C57BL/6 recipients simultaneously received donor BM (BALB/c) and donor T cells under costimulation blockade (anti-CD154 and CTLA4Ig). Donor CD4, but not CD8 cells, triggered natural killer-independent donor BM rejection which was associated with increased production of IL-6, interferon gamma (IFN-gamma) and IL-17A. BM rejection was prevented through neutralization of IL-6, but not of IFN-gamma or IL-17A. IL-6 counteracted the antiproliferative effect of anti-CD154 in vitro. Rapamycin and anti-lymphocyte function-associated antigen 1 negated this effect of IL-6 in vitro and prevented BM rejection in vivo. Simultaneous cotransplantation of (BALB/cxB6)F1, recipient or irradiated donor CD4 cells, or late transfer of donor CD4 cells did not lead to BM rejection, whereas cotransplantation of third party CD4 cells did. Transferred donor CD4 cells became activated, rapidly underwent apoptosis and triggered activation and proliferation of recipient T cells. Collectively, these results provide evidence that donor T cells recognizing the recipient as allogeneic lead to the release of IL-6, which abolishes the effect of anti-CD154, triggering donor BM rejection through bystander activation.

in vivo IFNγ neutralization
Maltby, S., et al. (2014). "Production and differentiation of myeloid cells driven by proinflammatory cytokines in response to acute pneumovirus infection in mice" J Immunol 193(8): 4072-4082. PubMed

Respiratory virus infections are often pathogenic, driving severe inflammatory responses. Most research has focused on localized effects of virus infection and inflammation. However, infection can induce broad-reaching, systemic changes that are only beginning to be characterized. In this study, we assessed the impact of acute pneumovirus infection in C57BL/6 mice on bone marrow hematopoiesis. We hypothesized that inflammatory cytokine production in the lung upregulates myeloid cell production in response to infection. We demonstrate a dramatic increase in the percentages of circulating myeloid cells, which is associated with pronounced elevations in inflammatory cytokines in serum (IFN-gamma, IL-6, CCL2), bone (TNF-alpha), and lung tissue (TNF-alpha, IFN-gamma, IL-6, CCL2, CCL3, G-CSF, osteopontin). Increased hematopoietic stem/progenitor cell percentages (Lineage(-)Sca-I(+)c-kit(+)) were also detected in the bone marrow. This increase was accompanied by an increase in the proportions of committed myeloid progenitors, as determined by colony-forming unit assays. However, no functional changes in hematopoietic stem cells occurred, as assessed by competitive bone marrow reconstitution. Systemic administration of neutralizing Abs to either TNF-alpha or IFN-gamma blocked expansion of myeloid progenitors in the bone marrow and also limited virus clearance from the lung. These findings suggest that acute inflammatory cytokines drive production and differentiation of myeloid cells in the bone marrow by inducing differentiation of committed myeloid progenitors. Our findings provide insight into the mechanisms via which innate immune responses regulate myeloid cell progenitor numbers in response to acute respiratory virus infection.

in vivo IFNγ neutralization
Choi, I. K., et al. (2013). "Oncolytic adenovirus expressing IL-23 and p35 elicits IFN-gamma- and TNF-alpha-co-producing T cell-mediated antitumor immunity" PLoS One 8(7): e67512. PubMed

Cytokine immunogene therapy is a promising strategy for cancer treatment. Interleukin (IL)-12 boosts potent antitumor immunity by inducing T helper 1 cell differentiation and stimulating cytotoxic T lymphocyte and natural killer cell cytotoxicity. IL-23 has been proposed to have similar but not overlapping functions with IL-12 in inducing Th1 cell differentiation and antitumor immunity. However, the therapeutic effects of intratumoral co-expression of IL-12 and IL-23 in a cancer model have yet to be investigated. Therefore, we investigated for the first time an effective cancer immunogene therapy of syngeneic tumors via intratumoral inoculation of oncolytic adenovirus co-expressing IL-23 and p35, RdB/IL23/p35. Intratumoral administration of RdB/IL23/p35 elicited strong antitumor effects and increased survival in a murine B16-F10 syngeneic tumor model. The levels of IL-12, IL-23, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) were elevated in RdB/IL23/p35-treated tumors. Moreover, the proportion of regulatory T cells was markedly decreased in mice treated with RdB/IL23/p35. Consistent with these data, mice injected with RdB/IL23/p35 showed massive infiltration of CD4(+) and CD8(+) T cells into the tumor as well as enhanced induction of tumor-specific immunity. Importantly, therapeutic mechanism of antitumor immunity mediated by RdB/IL23/p35 is associated with the generation and recruitment of IFN-gamma- and TNF-alpha-co-producing T cells in tumor microenvironment. These results provide a new insight into therapeutic mechanisms of IL-12 plus IL-23 and provide a potential clinical cancer immunotherapeutic agent for improved antitumor immunity.

in vitro IFNγ neutralization
Wu, H. Y., et al. (2011). "In vivo induction of Tr1 cells via mucosal dendritic cells and AHR signaling" PLoS One 6(8): e23618. PubMed

BACKGROUND: Type 1 regulatory T (Tr1) cells, characterized by the secretion of high levels of the anti-inflammatory cytokine interleukin-10 (IL-10), play an important role in the regulation of autoimmune diseases and transplantation. However, effective strategies that specifically induce Tr1 cells in vivo are limited. Furthermore, the pathways controlling the induction of these cells in vivo are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that nasal administration of anti-CD3 antibody induces suppressive Tr1 cells in mice. The in vivo induction of Tr1 cells by nasal anti-CD3 is dependent on IL-27 produced by upper airway resident dendritic cells (DCs), and is controlled by the transcription factors aryl hydrocarbon receptor (AHR) and c-Maf. Subsequently, IL-21 acts in an autocrine fashion to expand and maintain the Tr1 cells induced in vivo by nasally administered anti-CD3. CONCLUSIONS/SIGNIFICANCE: Our findings identify a unique approach to generate Tr1 cells in vivo and provide insights into the mechanisms by which these cells are induced.

in vivo IFNγ neutralization
Coley, S. M., et al. (2009). "IFN-gamma dictates allograft fate via opposing effects on the graft and on recipient CD8 T cell responses" J Immunol 182(1): 225-233. PubMed

CD8 T cells are necessary for costimulation blockade-resistant rejection. However, the mechanism by which CD8 T cells mediate rejection in the absence of major costimulatory signals is poorly understood. IFN-gamma promotes CD8 T cell-mediated immune responses, but IFN-gamma-deficient mice show early graft loss despite costimulation blockade. In contrast, we found that IFN-gamma receptor knockout mice show dramatically prolonged graft survival under costimulation blockade. To investigate this paradox, we addressed the effects of IFN-gamma on T cell alloresponses in vivo independent of the effects of IFN-gamma on graft survival. We identified a donor-specific CD8 T cell breakthrough response temporally correlated with costimulation blockade-resistant rejection. Neither IFN-gamma receptor knockout recipients nor IFN-gamma-deficient recipients showed a CD8 breakthrough response. Graft death on IFN-gamma-deficient recipients despite costimulation blockade could be explained by the lack of IFN-gamma available to act on the graft. Indeed, the presence of IFN-gamma was necessary for graft survival on IFN-gamma receptor knockout recipients, as either IFN-gamma neutralization or the lack of the IFN-gamma receptor on the graft precipitated early graft loss. Thus, IFN-gamma is required both for the recipient to mount a donor-specific CD8 T cell response under costimulation blockade as well as for the graft to survive after allotransplantation.

    • Neuroscience
    • ,
    Oral pathogens exacerbate Parkinson's disease by promoting Th1 cell infiltration in mice.

    In Microbiome on 17 November 2023 by Bai, X. B., Xu, S., et al.

    PubMed

    Parkinson's disease (PD) is a common chronic neurological disorder with a high risk of disability and no cure. Periodontitis is an infectious bacterial disease occurring in periodontal supporting tissues. Studies have shown that periodontitis is closely related to PD. However, direct evidence of the effect of periodontitis on PD is lacking. Here, we demonstrated that ligature-induced periodontitis with application of subgingival plaque (LIP-SP) exacerbated motor dysfunction, microglial activation, and dopaminergic neuron loss in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. The 16S rRNA gene sequencing revealed that LIP-SP induced oral and gut dysbiosis. Particularly, Veillonella parvula (V. parvula) and Streptococcus mutans (S. mutans) from oral ligatures were increased in the fecal samples of MPTP + LIP-SP treated mice. We further demonstrated that V. parvula and S. mutans played crucial roles in LIP-SP mediated exacerbation of motor dysfunction and neurodegeneration in PD mice. V. parvula and S. mutans caused microglial activation in the brain, as well as T helper 1 (Th1) cells infiltration in the brain, cervical lymph nodes, ileum and colon in PD mice. Moreover, we observed a protective effect of IFNγ neutralization on dopaminergic neurons in V. parvula- and S. mutans-treated PD mice. Our study demonstrates that oral pathogens V. parvula and S. mutans necessitate the existence of periodontitis to exacerbate motor dysfunction and neurodegeneration in MPTP-induced PD mice. The underlying mechanisms include alterations of oral and gut microbiota, along with immune activation in both brain and peripheral regions. Video Abstract. © 2023. The Author(s).

    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    RORγt-Raftlin1 complex regulates the pathogenicity of Th17 cells and colonic inflammation.

    In Nature Communications on 17 August 2023 by Singh, A. K., Kumar, R., et al.

    PubMed

    Th17 cells that produce Interleukin IL-17 are pathogenic in many human diseases, including inflammatory bowel disease, but are, paradoxically, essential for maintaining the integrity of the intestinal barrier in a non-inflammatory state. However, the intracellular mechanisms that regulate distinct transcriptional profiles and functional diversity of Th17 cells remain unclear. Here we show Raftlin1, a lipid raft protein, specifically upregulates and forms a complex with RORγt in pathogenic Th17 cells. Disruption of the RORγt-Raftlin1 complex results in the reduction of pathogenic Th17 cells in response to Citrobacter rodentium; however, there is no effect on nonpathogenic Th17 cells in response to commensal segmented filamentous bacteria. Mechanistically, we show that Raftlin1 recruits distinct phospholipids to RORγt and promotes the pathogenicity of Th17 cells. Thus, we have identified a mechanism that drives the pathogenic function of Th17 cells, which could provide a platform for advanced therapeutic strategies to dampen Th17-mediated inflammatory diseases. © 2023. Springer Nature Limited.

    • Immunology and Microbiology
    Lysophosphatidylcholine facilitates the pathogenesis of psoriasis through activating keratinocytes and T cells differentiation via glycolysis.

    In Journal of the European Academy of Dermatology and Venereology : JEADV on 1 July 2023 by Liu, P., Zhou, Y., et al.

    PubMed

    Although abnormal metabolism plays a critical role in the pathogenesis of psoriasis, the details are unclear. Here, we identified to explore the role and mechanism of lysophosphatidylcholine (LPC) on the pathogenesis of psoriasis. The level of LPC in plasma and skin lesions and the expression of G2A on skin lesions of psoriasis patients were detected by enzyme-linked immunosorbent assay, liquid chromatography-tandem mass spectrometry, or immunohistochemistry, respectively. The glycolysis in the skin lesions of imiquimod (IMQ)-induced psoriasis-like mouse model was detected by extracellular acidification rate. LPC was subcutaneously injected into IMQ-treated mouse ears, and the phenotype as well as the glycolysis were evaluated. Exploring the effects and mechanism of LPC on keratinocytes and CD4+ T cells by culturing primary keratinocytes and CD4+ T in vitro. We found that LPC was significantly increased both in the plasma and skin lesions of psoriatic patients, while G2A, exerting an essential role in LPC-inducing biological functions, was increased in psoriatic lesions. The abundance of LPC was positively correlated with glycolytic activity in the psoriasis-like mouse model. LPC treatment facilitated psoriasis-like inflammation and glycolytic activity in skin lesions. Mechanistically, the LPC/G2A axis significantly triggered glycolytic activity and produced inflammatory factors in keratinocytes, and blockade of glycolysis abrogated LPC-induced expression of inflammatory mediators in keratinocytes. LPC activated STAT1, resulting in recognition and binding to the promoters of GCK and PKLR, which are glycolytic rate-limiting enzymes. Furthermore, the LPC/G2A axis directly benefited Th1 differentiation, which was dependent on LPC-induced glycolytic activity. Notably, LPC indirectly facilitated Th17 differentiation by inducing the secretion of IL-1β in keratinocytes-T cells coculture system. Taken together, our findings revealed the role of the LPC/G2A axis in the pathogenesis of psoriasis; targeting LPC/G2A is a potential strategy for psoriasis therapy. © 2023 European Academy of Dermatology and Venereology.

    • FC/FACS
    • ,
    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    • ,
    • Immunology and Microbiology
    Enhancement of T cell infiltration via tumor-targeted Th9 cell delivery improves the efficacy of antitumor immunotherapy of solid tumors.

    In Bioactive Materials on 1 May 2023 by Chen, T., Xue, Y., et al.

    PubMed

    Insufficient infiltration of T cells severely compromises the antitumor efficacy of adoptive cell therapy (ACT) against solid tumors. Here, we present a facile immune cell surface engineering strategy aiming to substantially enhance the anti-tumor efficacy of Th9-mediated ACT by rapidly identifying tumor-specific binding ligands and improving the infiltration of infused cells into solid tumors. Non-genetic decoration of Th9 cells with tumor-targeting peptide screened from phage display not only allowed precise targeted ACT against highly heterogeneous solid tumors but also substantially enhanced infiltration of CD8+ T cells, which led to improved antitumor outcomes. Mechanistically, infusion of Th9 cells modified with tumor-specific binding ligands facilitated the enhanced distribution of tumor-killing cells and remodeled the immunosuppressive microenvironment of solid tumors via IL-9 mediated immunomodulation. Overall, we presented a simple, cost-effective, and cell-friendly strategy to enhance the efficacy of ACT against solid tumors with the potential to complement the current ACT. © 2022 The Authors.

    • Biochemistry and Molecular biology
    • ,
    • Cell Biology
    • ,
    • Immunology and Microbiology
    Lipidomic profiling reveals metabolic signatures in psoriatic skin lesions.

    In Clinical Immunology (Orlando, Fla.) on 1 January 2023 by Liu, P., Hou, G., et al.

    PubMed

    Psoriasis is a chronic immune-mediated inflammatory disease. Lipids play an important role in regulating the inflammatory response. However, the alteration of lipids involved in psoriasis particular in skin lesions remain unclear. Here, we performed the lipidomics to investigate lipid profiling in the skin lesions of the imiquimod-induced psoriasis-like dermatitis and psoriasis patients. The findings showed that ceramides phosphate (CerP) and ceramides were enriched in psoriatic lesions compared with controls from both psoriasis patients and psoriasis-like mouse model. Psoriasis patients were classified into two subtypes, the CC1 and CC2, by consensus clustering of these lipid signatures. The CC1 was characterized by the higher levels of CerP, uric acid, and more severe psoriasis, compared with CC2 subtype. Interestingly, ceramide-1-phosphate (C1P), dramatically enriched in CC1 subtype, facilitated imiquimod-induced psoriasis-like inflammatory responses. Mechanistically, C1P induced the expression of inflammatory factors and activated DNA replication and cell cycle signaling pathways in the primary keratinocytes. Inhibiting the production of C1P with ceramide kinase inhibitor effectively alleviated the imiquimod-induced psoriasis-like inflammation. Taken together, we described the landscape of lipids alteration and established lipids classification based on pattern of abundance of lipids in psoriatic skin lesions. Suppression of C1P pathway is a novel potential strategy for psoriasis treatment. Copyright © 2022. Published by Elsevier Inc.

    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    Pak2-mediated phosphorylation promotes RORγt ubiquitination and inhibits colonic inflammation.

    In Cell Reports on 13 September 2022 by Kathania, M., Kumar, R., et al.

    PubMed

    Dysregulated interleukin-17 (IL-17) expression and its downstream signaling is strongly linked to inflammatory bowel diseases (IBDs). However, the molecular mechanisms by which the function of RORγt, the transcription factor of IL-17, is regulated remains elusive. By a mass spectrometry-based approach, we identify that Pak2, a serine (S)/threonine (T) kinase, directly associates with RORγt. Pak2 recognizes a conserved KRLS motif within RORγt and phosphorylates the S-316 within this motif. Genetic deletion of Pak2 in Th17 cells reduces RORγt phosphorylation, increases IL-17 expression, and induces severe colitis upon adoptive transfer to Rag1-/- mice. Similarly, reconstitution of RORγt-S316A mutant in Rorc-/- Th17 cells enhances IL-17 expression and colitis severity. Mechanistically, we demonstrate that Pak2-mediated phosphorylation causes a conformational change resulting in exposure of the ubiquitin ligase Itch interacting PPLY motif and degradation of RORγt. Thus, we have uncovered a mechanism by which the activity of RORγt is regulated that can be exploited therapeutically. Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.

    • Immunology and Microbiology
    Evaluation of Glutaminolysis in T Cells.

    In Current Protocols on 1 September 2022 by Tajima, M. & Strober, W.

    PubMed

    The activity of living cells is necessarily dependent on the amount of available bioenergy. In T cells, the latter is mainly derived from ATP, a molecular energy "coin" generated by one of several metabolic processes that differ in their ability to satisfy energy demand. Thus, whereas naïve or quiescent T cells efficiently utilize oxidative phosphorylation to generate ATP, T cells subjected to antigenic stimulation followed by clonal expansion and cytokine production meet their increased need for energy by supplementing ATP generation by oxidative phosphorylation with ATP generation by glycolysis. Yet additional need for ATP can be met by other basic biologic sources of energy such as glutamine, an amino acid that is metabolized through a process called glutaminolysis to result in end products that flows into the TCA cycle and augment ATP generation by oxidative phosphorylation. It is now possible to track the dominant energy supplying processes (i.e., the ATP generation process) in differentiating or activated T cells in a real-time manner. Here, we provide one element of such tracking by describing protocols for the assessment of the contribution of glutaminolysis to overall ATP production within different T cell subsets. © 2022 Wiley Periodicals LLC. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Basic Protocol 1: Evaluation of the role of glutaminolysis during T cell activation/differentiation Basic Protocol 2: Evaluation of the role of glutaminolysis in T cell responses utilizing glutaminolysis inhibitors Basic Protocol 3: Evaluation of the effect of glutaminolysis on cellular oxidative phosphorylation/glycolysis. © 2022 Wiley Periodicals LLC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

    • Biochemistry and Molecular biology
    • ,
    • Cell Biology
    Lipidomic profiling reveals metabolic signatures in psoriatic skin lesions

    Preprint on Research Square on 27 July 2022 by Peng, C., Liu, P., et al.

    PubMed

    Psoriasis is a chronic immune-mediated inflammatory disease. Lipids play an important role in regulating the inflammatory response. However, the alteration of lipids involved in psoriasis particular in skin lesions remain unclear. Here, we performed the lipidomics to investigate lipid profiling in the skin lesions of the imiquimod-induced psoriasis-like dermatitis and psoriasis patients. The findings showed that ceramides phosphate (CerP) and ceramides were enriched in psoriatic lesions compared with controls from both psoriasis patients and psoriasis-like mouse model. Psoriasis patients were classified into two subtypes, the CC1 and CC2, by consensus clustering of these lipid signatures. The CC1 was characterized by the higher levels of CerP, uric acid, and more severe psoriasis, compared with CC2 subtype. Interestingly, ceramide-1-phosphate (C1P), dramatically enriched in CC1 subtype, facilitated imiquimod-induced psoriasis-like inflammatory responses. Mechanistically, C1P induced the expression of inflammatory factors and activated DNA replication and cell cycle signaling pathways in the primary keratinocytes. Inhibiting the production of C1P with ceramide kinase inhibitor effectively alleviated the imiquimod-induced psoriasis-like inflammation. Taken together, we described the landscape of lipids alteration and established lipids classification based on pattern of abundance of lipids in psoriatic skin lesions. Suppression of C1P pathway is a novel potential strategy for psoriasis treatment.

    • FC/FACS
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Re-programming mouse liver-resident invariant natural killer T cells for suppressing hepatic and diabetogenic autoimmunity.

    In Nature Communications on 7 June 2022 by Umeshappa, C. S., Solé, P., et al.

    PubMed

    Invariant NKT (iNKT) cells comprise a heterogeneous group of non-circulating, tissue-resident T lymphocytes that recognize glycolipids, including alpha-galactosylceramide (αGalCer), in the context of CD1d, but whether peripheral iNKT cell subsets are terminally differentiated remains unclear. Here we show that mouse and human liver-resident αGalCer/CD1d-binding iNKTs largely correspond to a novel Zbtb16+Tbx21+Gata3+MaflowRorc- subset that exhibits profound transcriptional, phenotypic and functional plasticity. Repetitive in vivo encounters of these liver iNKT (LiNKT) cells with intravenously delivered αGalCer/CD1d-coated nanoparticles (NP) trigger their differentiation into immunoregulatory, IL-10+IL-21-producing Zbtb16highMafhighTbx21+Gata3+Rorc- cells, termed LiNKTR1, expressing a T regulatory type 1 (TR1)-like transcriptional signature. This response is LiNKT-specific, since neither lung nor splenic tissue-resident iNKT cells from αGalCer/CD1d-NP-treated mice produce IL-10 or IL-21. Additionally, these LiNKTR1 cells suppress autoantigen presentation, and recognize CD1d expressed on conventional B cells to induce IL-10+IL-35-producing regulatory B (Breg) cells, leading to the suppression of liver and pancreas autoimmunity. Our results thus suggest that LiNKT cells are plastic for further functional diversification, with such plasticity potentially targetable for suppressing tissue-specific inflammatory phenomena. © 2022. The Author(s).

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Commensal Cryptosporidium colonization elicits a cDC1-dependent Th1 response that promotes intestinal homeostasis and limits other infections.

    In Immunity on 9 November 2021 by Russler-Germain, E. V., Jung, J., et al.

    PubMed

    Cryptosporidium can cause severe diarrhea and morbidity, but many infections are asymptomatic. Here, we studied the immune response to a commensal strain of Cryptosporidium tyzzeri (Ct-STL) serendipitously discovered when conventional type 1 dendritic cell (cDC1)-deficient mice developed cryptosporidiosis. Ct-STL was vertically transmitted without negative health effects in wild-type mice. Yet, Ct-STL provoked profound changes in the intestinal immune system, including induction of an IFN-γ-producing Th1 response. TCR sequencing coupled with in vitro and in vivo analysis of common Th1 TCRs revealed that Ct-STL elicited a dominant antigen-specific Th1 response. In contrast, deficiency in cDC1s skewed the Ct-STL CD4 T cell response toward Th17 and regulatory T cells. Although Ct-STL predominantly colonized the small intestine, colon Th1 responses were enhanced and associated with protection against Citrobacter rodentium infection and exacerbation of dextran sodium sulfate and anti-IL10R-triggered colitis. Thus, Ct-STL represents a commensal pathobiont that elicits Th1-mediated intestinal homeostasis that may reflect asymptomatic human Cryptosporidium infection. Copyright © 2021 Elsevier Inc. All rights reserved.

    • Cancer Research
    Immunogenic camptothesome nanovesicles comprising sphingomyelin-derived camptothecin bilayers for safe and synergistic cancer immunochemotherapy.

    In Nature Nanotechnology on 1 October 2021 by Wang, Z., Little, N., et al.

    PubMed

    Despite the enormous therapeutic potential of immune checkpoint blockade (ICB), it benefits only a small subset of patients. Some chemotherapeutics can switch 'immune-cold' tumours to 'immune-hot' to synergize with ICB. However, safe and universal therapeutic platforms implementing such immune effects remain scarce. We demonstrate that sphingomyelin-derived camptothecin nanovesicles (camptothesomes) elicit potent granzyme-B- and perforin-mediated cytotoxic T lymphocyte (CTL) responses, potentiating PD-L1/PD-1 co-blockade to eradicate subcutaneous MC38 adenocarcinoma with developed memory immunity. In addition, camptothesomes improve the pharmacokinetics and lactone stability of camptothecin, avoid systemic toxicities, penetrate deeply into the tumour and outperform the antitumour efficacy of Onivyde. Camptothesome co-load the indoleamine 2,3-dioxygenase inhibitor indoximod into its interior using the lipid-bilayer-crossing capability of the immunogenic cell death inducer doxorubicin, eliminating clinically relevant advanced orthotopic CT26-Luc tumours and late-stage B16-F10-Luc2 melanoma, and achieving complete metastasis remission when combined with ICB and folate targeting. The sphingomyelin-derived nanotherapeutic platform and doxorubicin-enabled transmembrane transporting technology are generalizable to various therapeutics, paving the way for transformation of the cancer immunochemotherapy paradigm. © 2021. The Author(s), under exclusive licence to Springer Nature Limited.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Epithelium-autonomous NAIP/NLRC4 prevents TNF-driven inflammatory destruction of the gut epithelial barrier in Salmonella-infected mice.

    In Mucosal Immunology on 1 May 2021 by Fattinger, S. A., Geiser, P., et al.

    PubMed

    The gut epithelium is a critical protective barrier. Its NAIP/NLRC4 inflammasome senses infection by Gram-negative bacteria, including Salmonella Typhimurium (S.Tm) and promotes expulsion of infected enterocytes. During the first ~12-24 h, this reduces mucosal S.Tm loads at the price of moderate enteropathy. It remained unknown how this NAIP/NLRC4-dependent tradeoff would develop during subsequent infection stages. In NAIP/NLRC4-deficient mice, S.Tm elicited severe enteropathy within 72 h, characterized by elevated mucosal TNF (>20 pg/mg) production from bone marrow-derived cells, reduced regeneration, excessive enterocyte loss, and a collapse of the epithelial barrier. TNF-depleting antibodies prevented this destructive pathology. In hosts proficient for epithelial NAIP/NLRC4, a heterogeneous enterocyte death response with both apoptotic and pyroptotic features kept S.Tm loads persistently in check, thereby preventing this dire outcome altogether. Our results demonstrate that immediate and selective removal of infected enterocytes, by locally acting epithelium-autonomous NAIP/NLRC4, is required to avoid a TNF-driven inflammatory hyper-reaction that otherwise destroys the epithelial barrier.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Niche-specific MHC II and PD-L1 regulate CD4+CD8αα+ intraepithelial lymphocyte differentiation.

    In The Journal of Experimental Medicine on 5 April 2021 by Moon, S., Park, Y., et al.

    PubMed

    Conventional CD4+ T cells are differentiated into CD4+CD8αα+ intraepithelial lymphocytes (IELs) in the intestine; however, the roles of intestinal epithelial cells (IECs) are poorly understood. Here, we showed that IECs expressed MHC class II (MHC II) and programmed death-ligand 1 (PD-L1) induced by the microbiota and IFN-γ in the distal part of the small intestine, where CD4+ T cells were transformed into CD4+CD8αα+ IELs. Therefore, IEC-specific deletion of MHC II and PD-L1 hindered the development of CD4+CD8αα+ IELs. Intracellularly, PD-1 signals supported the acquisition of CD8αα by down-regulating the CD4-lineage transcription factor, T helper-inducing POZ/Krüppel-like factor (ThPOK), via the Src homology 2 domain-containing tyrosine phosphatase (SHP) pathway. Our results demonstrate that noncanonical antigen presentation with cosignals from IECs constitutes niche adaptation signals to develop tissue-resident CD4+CD8αα+ IELs. © 2021 Moon et al.

    • In Vitro
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Gut Helicobacter presentation by multiple dendritic cell subsets enables context-specific regulatory T cell generation.

    In eLife on 3 February 2021 by Russler-Germain, E. V., Yi, J., et al.

    PubMed

    Generation of tolerogenic peripheral regulatory T (pTreg) cells is commonly thought to involve CD103+ gut dendritic cells (DCs), yet their role in commensal-reactive pTreg development is unclear. Using two Helicobacter-specific T cell receptor (TCR) transgenic mouse lines, we found that both CD103+ and CD103- migratory, but not resident, DCs from the colon-draining mesenteric lymph node presented Helicobacter antigens to T cells ex vivo. Loss of most CD103+ migratory DCs in vivo using murine genetic models did not affect the frequency of Helicobacter-specific pTreg cell generation or induce compensatory tolerogenic changes in the remaining CD103- DCs. By contrast, activation in a Th1-promoting niche in vivo blocked Helicobacter-specific pTreg generation. Thus, these data suggest a model where DC-mediated effector T cell differentiation is 'dominant', necessitating that all DC subsets presenting antigen are permissive for pTreg cell induction to maintain gut tolerance.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    STING agonist promotes CAR T cell trafficking and persistence in breast cancer.

    In The Journal of Experimental Medicine on 1 February 2021 by Xu, N., Palmer, D. C., et al.

    PubMed

    CAR T therapy targeting solid tumors is restrained by limited infiltration and persistence of those cells in the tumor microenvironment (TME). Here, we developed approaches to enhance the activity of CAR T cells using an orthotopic model of locally advanced breast cancer. CAR T cells generated from Th/Tc17 cells given with the STING agonists DMXAA or cGAMP greatly enhanced tumor control, which was associated with enhanced CAR T cell persistence in the TME. Using single-cell RNA sequencing, we demonstrate that DMXAA promoted CAR T cell trafficking and persistence, supported by the generation of a chemokine milieu that promoted CAR T cell recruitment and modulation of the immunosuppressive TME through alterations in the balance of immune-stimulatory and suppressive myeloid cells. However, sustained tumor regression was accomplished only with the addition of anti-PD-1 and anti-GR-1 mAb to Th/Tc17 CAR T cell therapy given with STING agonists. This study provides new approaches to enhance adoptive T cell therapy in solid tumors. © 2020 Xu et al.

    • Cell Culture
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Urolithin A ameliorates experimental autoimmune encephalomyelitis by targeting aryl hydrocarbon receptor.

    In EBioMedicine on 1 February 2021 by Shen, P. X., Li, X., et al.

    PubMed

    Urolithin A (URA) is an intestinal microbiota metabolic product from ellagitannin-containing foods with multiple biological activities. However, its role in autoimmune diseases is largely unknown. Here, for first time, we demonstrate the therapeutic effect of URA in an experimental autoimmune encephalomyelitis (EAE) animal model. Therapeutic effect was evaluated via an active and passive EAE animal model in vivo. The function of URA on bone marrow-derived dendritic cells (BM-DCs), T cells, and microglia were tested in vitro. Oral URA (25 mg/kg/d) suppressed disease progression at prevention, induction, and effector phases of preclinical EAE. Histological evaluation showed that significantly fewer inflammatory cells, decreased demyelination, lower numbers of M1-type microglia and activated DCs, as well as reduced infiltrating Th1/Th17 cells were present in the central nervous system (CNS) of the URA-treated group. URA treatment at 25 μM inhibited the activation of BM-DCs in vitro, restrained Th17 cell differentiation in T cell polarization conditions, and in a DC-CD4+ T cell co-culture system. Moreover, we confirmed URA inhibited pathogenicity of Th17 cells in adoptive EAE. Mechanism of URA action was directly targeting Aryl Hydrocarbon Receptor (AhR) and modulating the signaling pathways. Collectively, our study offers new evidence that URA, as a human microbial metabolite, is valuable to use as a prospective therapeutic candidate for autoimmune diseases. Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.

    • Genetics
    • ,
    • Immunology and Microbiology
    Dynamic single-cell RNA sequencing identifies immunotherapy persister cells following PD-1 blockade.

    In The Journal of Clinical Investigation on 19 January 2021 by Sehgal, K., Portell, A. J., et al.

    PubMed

    Resistance to oncogene-targeted therapies involves discrete drug-tolerant persister cells, originally discovered through in vitro assays. Whether a similar phenomenon limits efficacy of programmed cell death 1 (PD-1) blockade is poorly understood. Here, we performed dynamic single-cell RNA-Seq of murine organotypic tumor spheroids undergoing PD-1 blockade, identifying a discrete subpopulation of immunotherapy persister cells (IPCs) that resisted CD8+ T cell-mediated killing. These cells expressed Snai1 and stem cell antigen 1 (Sca-1) and exhibited hybrid epithelial-mesenchymal features characteristic of a stem cell-like state. IPCs were expanded by IL-6 but were vulnerable to TNF-α-induced cytotoxicity, relying on baculoviral IAP repeat-containing protein 2 (Birc2) and Birc3 as survival factors. Combining PD-1 blockade with Birc2/3 antagonism in mice reduced IPCs and enhanced tumor cell killing in vivo, resulting in durable responsiveness that matched TNF cytotoxicity thresholds in vitro. Together, these data demonstrate the power of high-resolution functional ex vivo profiling to uncover fundamental mechanisms of immune escape from durable anti-PD-1 responses, while identifying IPCs as a cancer cell subpopulation targetable by specific therapeutic combinations.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    • ,
    • Neuroscience
    Control of B Cell Lymphoma by Gammaherpesvirus-Induced Memory CD8 T Cells.

    In The Journal of Immunology on 15 December 2020 by Preiss, N. K., Kang, T., et al.

    PubMed

    Persistent infection with gammaherpesviruses (γHV) can cause lymphomagenesis in immunocompromised patients. Murine γHV-68 (MHV-68) is an important tool for understanding immune factors contributing to γHV control; however, modeling control of γHV-associated lymphomagenesis has been challenging. Current model systems require very long incubation times or severe immune suppression, and tumor penetrance is low. In this report, we describe the generation of a B cell lymphoma on the C57BL/6 background, which is driven by the Myc oncogene and expresses an immunodominant CD8 T cell epitope from MHV-68. We determined MHV-68-specific CD8 T cells in latently infected mice use either IFN-γ or perforin/granzyme to control γHV-associated lymphoma, but perforin/granzyme is a more potent effector mechanism for lymphoma control than IFN-γ. Consistent with previous reports, CD4-depleted mice lost control of virus replication in persistently infected mice. However, control of lymphoma remained intact in the absence of CD4 T cells. Collectively, these data show the mechanisms of T cell control of B cell lymphoma in γHV-infected mice overlap with those necessary for control of virus replication, but there are also important differences. This study establishes a tool for further dissecting immune surveillance against, and optimizing adoptive T cell therapies for, γHV-associated lymphomas. Copyright © 2020 by The American Association of Immunologists, Inc.

    • Immunology and Microbiology
    Interferon-γ/Interleukin-27 Axis Induces Programmed Death Ligand 1 Expression in Monocyte-Derived Dendritic Cells and Restores Immune Tolerance in Central Nervous System Autoimmunity.

    In Frontiers in Immunology on 17 November 2020 by Casella, G., Rasouli, J., et al.

    PubMed

    Antigen (Ag)-specific tolerance induction by intravenous (i. v.) injection of high-dose auto-Ags has been explored for therapy of autoimmune diseases, including multiple sclerosis (MS). It is thought that the advantage of such Ag-specific therapy over non-specific immunomodulatory treatments would be selective suppression of a pathogenic immune response without impairing systemic immunity, thus avoiding adverse effects of immunosuppression. Auto-Ag i.v. tolerance induction has been extensively studied in experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and limited clinical trials demonstrated that it is safe and beneficial to a subset of MS patients. Nonetheless, the mechanisms of i.v. tolerance induction are incompletely understood, hampering the development of better approaches and their clinical application. Here, we describe a pathway whereby auto-Ag i.v. injected into mice with ongoing clinical EAE induces interferon-gamma (IFN-γ) secretion by auto-Ag-specific CD4+ T cells, triggering interleukin (IL)-27 production by conventional dendritic cells type 1 (cDC1). IL-27 then, via signal transducer and activator of transcription 3 activation, induces programmed death ligand 1 (PD-L1) expression by monocyte-derived dendritic cells (moDCs) in the central nervous system of mice with EAE. PD-L1 interaction with programmed cell death protein 1 on pathogenic CD4+ T cells leads to their apoptosis/anergy, resulting in disease amelioration. These findings identify a key role of the IFN-γ/IL-27/PD-L1 axis, involving T cells/cDC1/moDCs in the induction of i.v. tolerance. Copyright © 2020 Casella, Rasouli, Thome, Descamps, Vattikonda, Ishikawa, Boehm, Hwang, Zhang, Xiao, Park, Zhang, Alvarez, Rostami and Ciric.

    Th2 Cytokine Modulates Herpesvirus Reactivation in a Cell Type Specific Manner

    Preprint on BioRxiv : the Preprint Server for Biology on 1 October 2020 by Wang, G., Zarek, C., et al.

    PubMed

    Gammaherpesviruses, such as Epstein-Barr virus (EBV), Kaposi’s sarcoma associated virus (KSHV), and murine γ-herpesvirus 68 (MHV68), establish latent infection in B cells, macrophages, and non-lymphoid cells, and can induce both lymphoid and non-lymphoid cancers. Research on these viruses has relied heavily on immortalized B cell and endothelial cell lines. Therefore, we know very little about the cell type specific regulation of virus infection. We have previously shown that treatment of MHV68-infected macrophages with the cytokine interleukin-4 (IL-4) or challenge of MHV68-infected mice with an IL-4-inducing parasite leads to virus reactivation. However, we do not know if all latent reservoirs of the virus, including B cells, reactivate the virus in response to IL-4. Here we used an in vivo approach to address the question of whether all latently infected cell types reactivate MHV68 in response to a particular stimulus. We found that IL-4 receptor expression on macrophages was required for IL-4 to induce virus reactivation, but that it was dispensable on B cells. We further demonstrated that the transcription factor, STAT6, which is downstream of the IL-4 receptor and binds a viral promoter in macrophages, did not bind to the viral promoter in B cells. These data suggest that stimuli that promote herpesvirus reactivation may only affect latent virus in particular cell types, but not in others. h4>Importance/h4> Herpesviruses establish life-long quiescent infections in specific cells in the body, and only reactivate to produce infectious virus when precise signals induce them to do so. The signals that induce herpesvirus reactivation are often studied only in one particular cell type infected with the virus. However, herpesviruses establish latency in multiple cell types in their hosts. Using murine gammaherpesvirus-68 (MHV68) and conditional knockout mice, we examined the cell type specificity of a particular reactivation signal, interleukin-4 (IL-4). We found that IL-4 only induced herpesvirus reactivation from macrophages, but not from B cells. This work indicates that regulation of virus latency and reactivation is cell type specific. This has important implications for therapies aimed at either promoting or inhibiting reactivation for the control or elimination of chronic viral infections.

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