Myd88 Initiates Early Innate Immune Responses and Promotes CD4 T Cells during Coronavirus Encephalomyelitis

ABSTRACTMyd88 signaling is critical to the control of numerous central nervous system (CNS) infections by promoting both innate and adaptive immune responses. Nevertheless, the extent to which Myd88 regulates type I interferon (IFN) versus proinflammatory factors and T cell function, as well as the anatomical site of action, varies extensively with the pathogen. CNS infection by neurotropic coronavirus with replication confined to the brain and spinal cord induces protective IFN-α/β via Myd88-independent activation of melanoma differentiation-associated gene 5 (MDA5). However, a contribution of Myd88-dependent signals to CNS pathogenesis has not been assessed. Infected Myd88−/−mice failed to control virus, exhibited enhanced clinical disease coincident with increased demyelination, and succumbed to infection within 3 weeks. The induction of IFN-α/β, as well as of proinflammatory cytokines and chemokines, was impaired early during infection. However, defects in both IFN-α/β and select proinflammatory factors were rapidly overcome prior to T cell recruitment. Myd88 deficiency also specifically blunted myeloid and CD4 T cell recruitment into the CNS without affecting CD8 T cells. Moreover, CD4 T cells but not CD8 T cells were impaired in IFN-γ production. Ineffective virus control indeed correlated most prominently with reduced antiviral IFN-γ in the CNS of Myd88−/−mice. The results demonstrate a crucial role for Myd88 both in early induction of innate immune responses during coronavirus-induced encephalomyelitis and in specifically promoting protective CD4 T cell activation. In the absence of these responses, functional CD8 T cells are insufficient to control viral spread within the CNS, resulting in severe demyelination.IMPORTANCEDuring central nervous system (CNS) infections, signaling through the adaptor protein Myd88 promotes both innate and adaptive immune responses. The extent to which Myd88 regulates antiviral type I IFN, proinflammatory factors, adaptive immunity, and pathology is pathogen dependent. These results reveal that Myd88 protects from lethal neurotropic coronavirus-induced encephalomyelitis by accelerating but not enhancing the induction of IFN-α/β, as well as by promoting peripheral activation and CNS accumulation of virus-specific CD4 T cells secreting IFN-γ. By controlling both early innate immune responses and CD4 T cell-mediated antiviral IFN-γ, Myd88 signaling limits the initial viral dissemination and is vital for T cell-mediated control of viral loads. Uncontrolled viral replication in the absence of Myd88 leads to severe demyelination and pathology despite overall reduced inflammatory responses. These data support a vital role of Myd88 signaling in protective antimicrobial functions in the CNS by promoting proinflammatory mediators and T cell-mediated IFN-γ production.

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CD8 T Cells in Innate Immune Responses: Using STAT4-Dependent but Antigen-Independent Pathways to Gamma Interferon during Viral Infection

mBio ◽

10.1128/mbio.01978-14 ◽

2014 ◽

Vol 5 (5) ◽

Cited By ~ 15

Author(s):

Jenny E. Suarez-Ramirez ◽

Margarite L. Tarrio ◽

Kwangsin Kim ◽

Delia A. Demers ◽

Christine A. Biron

Keyword(s):

Innate Immunity ◽

T Cells ◽

Immune Responses ◽

Cd8 T Cells ◽

Gamma Interferon ◽

Innate Immune ◽

Interleukin 12 ◽

Innate Immune Responses ◽

Ifn Γ

ABSTRACT The cytokine gamma interferon (IFN-γ), with antimicrobial and immunoregulatory functions, can be produced by T cells following stimulation through their T cell receptors (TCRs) for antigen. The innate cytokines type 1 IFNs and interleukin-12 (IL-12) can also stimulate IFN-γ production by natural killer (NK) but not naive T cells. High basal expression of signal transducer and activator of transcription 4 (STAT4), used by type 1 IFN and IL-12 to induce IFN-γ as well as CD25, contributes to the NK cell responses. During acute viral infections, antigen-specific CD8 T cells are stimulated to express elevated STAT4 and respond to the innate factors with IFN-γ production. Little is known about the requirements for cytokine compared to TCR stimulation. Primary infections of mice with lymphocytic choriomeningitis virus (LCMV) demonstrated that although the elicited antigen-specific CD8 T cells acquired STAT4-dependent innate cytokine responsiveness for IFN-γ and CD25 induction ex vivo, TCR stimulation induced these through STAT4-independent pathways. During secondary infections, LCMV-immune CD8 T cells had STAT4-dependent IFN-γ expression at times of innate cytokine induction but subsequently expanded through STAT4-independent pathways. At times of innate cytokine responses during infection with the antigen-distinct murine cytomegalovirus virus (MCMV), NK and LCMV-immune CD8 T cells both had activation of pSTAT4 and IFN-γ. The T cell IFN-γ response was STAT4 and IL-12 dependent, but antigen-dependent expansion was absent. By dissecting requirements for STAT4 and antigen, this work provides novel insights into the endogenous regulation of cytokine and proliferative responses and demonstrates conditioning of innate immunity by experience. IMPORTANCE Understanding the regulation and function of adaptive immunity is key to the development of new and improved vaccines. Its CD8 T cells are activated through antigen-specific receptors to contribute to long-lasting immunity after natural infections or purposeful immunization. The antigen-receptor pathway of stimulation can lead to production of gamma interferon (IFN-γ), a cytokine having both direct antimicrobial and immunoregulatory functions. Natural killer cells can also produce IFN-γ in response to the innate cytokines type 1 IFNs and/or interleukin-12. This work demonstrates that CD8 T cells acquire parallel responsiveness to innate cytokine signaling for IFN-γ expression during their selection and development and maintain this capability to participate in innate immune responses as long-lived memory cells. Thus, CD8 T cells are conditioned to play a role in innate immunity, and their presence under immune conditions has the potential to regulate resistance to either secondary challenges or primary infections with unrelated agents.

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Identification of the AAV2 Capsid CD8+ T Cell Epitope in C57BL/6 Mice.

Blood ◽

10.1182/blood.v104.11.3188.3188 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3188-3188

Author(s):

Denise E. Sabatino ◽

Federico Mingozzi ◽

Haifeng Chen ◽

Peter Colosi ◽

Hildegund C.J. Ertl ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Responses ◽

Capsid Protein ◽

Cd8 T Cells ◽

Cell Epitope ◽

T Cell Response ◽

Cd8 Cells ◽

Media Control ◽

Ifn Γ

Abstract Recently, a clinical trial for adeno-associated virus serotype 2 (AAV2) mediated liver directed gene transfer of human Factor IX to subjects with severe hemophilia B revealed that two patients developed transient asymptomatic transaminitis following vector administration. Immunology studies in the second patient demonstrated a transient T cell response to AAV2 capsid peptides suggesting that the immune response to the AAV capsid may be related to the transient transaminitis. We hypothesized that the observations made in the human subjects were due to a CD8 T cell response to AAV2 capsid protein. Preclinical studies in mice and dogs, which are not naturally infected by wild type AAV2 viruses, did not predict these findings in the clinical study. Thus, we developed a mouse model in which we were able to mimic this phenomenon (Blood 102:493a). In an effort to further characterize the immune responses to AAV2 capsid proteins in this mouse model, we identified the T cell epitope in the AAV capsid protein recognized by murine C57Bl/6 CD8 T cells. A peptide library of AAV2 VP1 capsid peptides (n=145) that were synthesized as 15mers overlapping by 10 amino acids were divided into 6 pools each containing 24–25 peptides. C57Bl/6 mice were immunized intramuscularly with an adenovirus expressing AAV2 capsid protein. Nine days later the spleen was harvested and intracellular cytokine staining (ICS) was used to assess release of IFN-γ from CD8 T cells in response to 6 AAV2 capsid peptide pools. ICS demonstrated CD8 cells from mice immunized with Ad-AAV2 produced IFN-γ (3.5% of the CD8 cells) in response to Pool F (amino acid 119–145) while no IFN-γ release in CD8 cells was detected with Pool A to E (mean 0.28%±0.25%) compared to the media control (0.16%). This detection of IFN-γ release from CD8 T cells indicates a specific proliferation to a peptide(s) within this peptide pool (Pool F). A matrix approach was used to further define which peptide(s) contained the immunodominant epitope. Eleven small peptide pools of Pool F were created in which each peptide was represented in 2 pools. ICS of splenocytes from immunized (Ad-AAV2 capsid) C57Bl/6 mice demonstrated IFN-γ response from CD8 cells to 3 of the matrix pools corresponding to peptide 140 (PEIQYTSNYNKSVNV) and 141 (TSNYNKSVNVDFTVD) compared with media controls. To determine the exact peptide sequence that binds to the MHC Class I molecule, 9 amino acid peptides (n=7) were created that overlap peptide 140 and 141. Peptide SNYNKSVNV showed positive staining for both CD8 and IFN- γ(3.2%) compared with the six other peptides (0.14%±0.08%), media control (0.08%) and mice that were not immunized (0.11%). This epitope lies in the C terminus of the AAV2 VP1 capsid protein. Current studies using strains of mice with different MHC H2 haplotypes will allow us to determine which of the C57Bl/6 MHC alleles the epitope binds. These findings will provide us with a powerful tool for assessing immune responses to AAV capsid in the context of gene therapy. Specifically, they will allow us to determine how long immunologically detectable capsid sequences persist in an animal injected with AAV vectors. This in turn will provide a basis for a clinical study in which subjects are transiently immunosuppressed, from the time of vector injection until capsid epitopes are no longer detectable by the immune system.

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Donor Immunization with WT1 Peptide Augments Anti-Leukemic Activity After MHC-Matched Bone Marrow Transplantation

Blood ◽

10.1182/blood.v118.21.1896.1896 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1896-1896

Author(s):

Holbrook E Kohrt ◽

Antonia MS Mueller ◽

Jeanette B Baker ◽

Matthew J Goldstein ◽

Evan Newell ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Tumor Antigen ◽

Cd4 T Cell ◽

Leukemia Cells ◽

Peptide Vaccination ◽

Tumor Bearing ◽

Ifn Γ ◽

Anti Tumor Activity

Abstract Abstract 1896 The curative potential of MHC-matched allogeneic bone marrow transplantation (BMT) is in part due to immunologic graft-versus-tumor (GvT) reactions mediated by donor T cells that recognize host minor histocompatibility antigens. Immunization with leukemia-associated antigens, such as Wilm's Tumor 1 (WT1) peptides, induces a T cell population that is tumor antigen specific. We determined whether BMT combined with immunotherapy using WT1 peptide vaccination of donors induced more potent anti-tumor activity when combined with allotransplantation. WT1 peptide vaccinations of healthy syngeneic or allogeneic donor mice with a 9-mer WT1 peptide (amino acids 126–134, the WT1 9-mer which has the highest binding affinity for H-2Db) and Incomplete Freund's Adjuvant induced CD8+ T cells that were specifically reactive to WT1-expressing FBL3 leukemia cells. We found that compared to vaccination with IFA alone, four weekly WT1 vaccinations induced an increased percentage of WT1-tetramer+CD8 T-cells (0.15% vs. 1%) in the peripheral blood 28 days following the first vaccination (Figure A *p<.001). CD8 T-cells producing IFN-γ+ after co-culture with tumor cells were similarly increased (0.11% vs. 13.6%) at this timepoint (Figure B *p<.001). They were CD44hi suggesting a memory phenotype, specifically reactive to WT1-expressing tumor (FBL3 and not H11), and increased in a vaccination dose-dependent fashion (Figure A and B). Four weekly WT1 vaccinations prevented tumor growth in donors following intravenous leukemia challenge. In contrast, in tumor-bearing mice, WT1 vaccinations failed to induce WT1-tetramer+ or IFN-γ+ CD8 T-cells and were ineffective as a therapeutic vaccine based on intensity of bioluminescence from luciferase-labeled FBL3 leukemia and mortality. BMT from WT1 vaccinated MHC-matched donors including LP/J and C3H.SW, but not C57BL/6 syngeneic donors, into C57BL/6 recipient tumor-bearing mice was effective as a therapeutic maneuver and resulted in eradication of luciferase-labeled FBL3 leukemia and survival of 70–90% of mice. Interestingly, the transfer of total CD8+ T cells from immunized donors was more effective than the transfer of WT1-tetramer+CD8+ T cells, likely as a result of alloreactive and tumor-antigen reactive T cells contained with the donor total CD8+ T cells. Total and tetramer+CD8+ T cells required CD4+ T cell help for maximal anti-tumor activity, which was equivalent in efficacy from immunized or unimmunized CD4+ T cell donors. Total CD4+ T cells, alone, from immunized donors provided no anti-tumor activity. The infused donor LP/J or C3H.SW CD8+ T cells collected from cured C57BL/6 recipients, were highly reactive against WT1-expressing FBL3 leukemia cells (14% IFN-γ+) compared to non-WT1-expressing H11 leukemia cells (5% IFN-γ+). The circulating, WT1-tetramer+CD8+ T cell population expanded in cured recipients, peaking at 3.5% on day 50 and contracting through day 100 post-BMT to 0.56%. These findings show that peptide vaccination of donor mice with a tumor antigen dramatically enhances GvT activity and is synergistic with allogeneic BMT. This novel and broadly applicable approach, using leukemia-associated antigen immunization to enhance GvT by creating an “educated” donor T cell graft for allogeneic transplantation of patients with acute myeloid leukemia and myelodysplastic syndrome, is currently being translated to a Phase 1 clinical trial at our institution. Disclosures: No relevant conflicts of interest to declare.

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Organ- and Disease-Stage-Specific Regulation of Toxoplasma gondii-Specific CD8-T-Cell Responses by CD4 T Cells

Infection and Immunity ◽

10.1128/iai.00098-06 ◽

2006 ◽

Vol 74 (10) ◽

pp. 5790-5801 ◽

Cited By ~ 26

Author(s):

Sonja Lütjen ◽

Sabine Soltek ◽

Simona Virna ◽

Martina Deckert ◽

Dirk Schlüter

Keyword(s):

T Cells ◽

T Cell ◽

Toxoplasma Gondii ◽

Cd8 T Cells ◽

Functional Activity ◽

Cd4 T Cells ◽

Cd8 T Cell ◽

Cd4 T Cell ◽

Ifn Γ

ABSTRACT Toxoplasma gondii induces a persistent central nervous system infection, which may be lethally reactivated in AIDS patients with low CD4 T-cell numbers. To analyze the role of CD4 T cells for the regulation of parasite-specific CD8 T cells, mice were infected with transgenic T. gondii expressing the CD8 T-cell antigen β-galactosidase (β-Gal). Depletion of CD4 T cells prior to infection did not affect frequencies of β-Gal876-884-specific (consisting of residues 876 to 884 of β-Gal) CD8 T cells but resulted in a pronounced reduction of intracerebral β-Gal-specific gamma interferon (IFN-γ)-producing and cytolytic CD8 T cells. After cessation of anti-CD4 treatment a normal T. gondii-specific CD4 T-cell response developed, but IFN-γ production of intracerebral β-Gal-specific CD8 T cells remained impaired. The important supportive role of CD4 T cells for the optimal functional activity of intracerebral CD8 T cells was also observed in mice that had been depleted of CD4 T cells during chronic toxoplasmosis. Reinfection of chronically infected mice that had been depleted of CD4 T cells during either the acute or chronic stage of infection resulted in an enhanced proliferation of β-Gal-specific IFN-γ-producing splenic CD8 T cells. However, reinfection of chronically infected mice that had been depleted of CD4 T cells in the acute stage of infection did not reverse the impaired IFN-γ production of intracerebral CD8 T cells. Collectively, these findings illustrate that CD4 T cells are not required for the induction and maintenance of parasite-specific CD8 T cells but, depending on the stage of infection, the infected organ and parasite challenge infection regulate the functional activity of intracerebral CD8 T cells.

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The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

Journal of Immunology Research ◽

10.1155/2021/6625855 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Kunlong Xiong ◽

Jinxia Niu ◽

Ruijuan Zheng ◽

Zhonghua Liu ◽

Yanzheng Song ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Mononuclear Cells ◽

Cd4 T Cell ◽

Cell Frequency ◽

Tnf Α ◽

Ifn Γ

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4+ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4+ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37RV with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4+ and CD8+ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4+ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4+ and CD8+ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4+ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4+ T cells. β-Catenin along with PD-1 and IFN-γ in CD4+ T cells had a high correlation with those in CD8+ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4+ T cell frequency in TB.

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Faculty Opinions recommendation of CD8 T cells in innate immune responses: using STAT4-dependent but antigen-independent pathways to gamma interferon during viral infection.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.723553947.793501609 ◽

2014 ◽

Author(s):

Tian Wang

Keyword(s):

T Cells ◽

Immune Responses ◽

Viral Infection ◽

Cd8 T Cells ◽

Gamma Interferon ◽

Innate Immune ◽

Innate Immune Responses

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Donor CD8 T Cells and IFN-γ Are Critical for Sex-Based Differences in Donor CD4 T Cell Engraftment and Lupus-Like Phenotype in Short-Term Chronic Graft-Versus-Host Disease Mice

The Journal of Immunology ◽

10.4049/jimmunol.1001074 ◽

2011 ◽

Vol 186 (11) ◽

pp. 6238-6254 ◽

Cited By ~ 10

Author(s):

Anthony D. Foster ◽

Kateryna Soloviova ◽

Irina Puliaeva ◽

Maksym Puliaiev ◽

Roman Puliaev ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Graft Versus Host Disease ◽

Cd8 T Cells ◽

Cd4 T Cell ◽

Short Term ◽

Host Disease ◽

Graft Versus Host ◽

Cell Engraftment ◽

Ifn Γ

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IFN-γ expression in CD8+ T cells regulated by IL-6 signal is involved in superantigen-mediated CD4+ T cell death

International Immunology ◽

10.1093/intimm/dxn125 ◽

2008 ◽

Vol 21 (1) ◽

pp. 73-80 ◽

Cited By ~ 9

Author(s):

Toru Atsumi ◽

Masae Sato ◽

Daisuke Kamimura ◽

Arisa Moroi ◽

Yoichiro Iwakura ◽

...

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cell ◽

Ifn Γ

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Persistent numbers of tetramer+ CD8+ T cells, but loss of interferon-γ+ HIV-specific T cells during progression to AIDS

Blood ◽

10.1182/blood.v99.7.2505 ◽

2002 ◽

Vol 99 (7) ◽

pp. 2505-2511 ◽

Cited By ~ 138

Author(s):

Stefan Kostense ◽

Kristin Vandenberghe ◽

Jeanine Joling ◽

Debbie Van Baarle ◽

Nening Nanlohy ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cell Activity ◽

Cd8 T Cell ◽

Interferon Γ ◽

Cd4 T Cell ◽

Cytotoxic T Cell ◽

Cell Counts ◽

Ifn Γ

Although CD8+ T cells initially suppress human immunodeficiency virus (HIV) replication, cytotoxic T-cell precursor frequencies eventually decline and fail to prevent disease progression. In a longitudinal study including 16 individuals infected with HIV-1, we studied both the number and function of HIV-specific CD8+ T cells by comparing HLA-peptide tetramer staining and peptide-induced interferon-γ (IFN-γ) production. Numbers of IFN-γ–producing T cells declined during progression to acquired immunodeficiency syndrome (AIDS), whereas the number of tetramer+ T cells in many individuals persisted at high frequencies. Loss of IFN-γ–producing T cells correlated with declining CD4+ T-cell counts, consistent with the need of CD4+ T-cell help in maintaining adequate CD8+T-cell function. These data indicate that the loss of HIV-specific CD8+ T-cell activity is not due to physical depletion, but is mainly due to progressively impaired function of HIV-specific CD8+ T cells.

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