Susceptible Mouse Strains Research Articles

Cytotoxic CD8+ T cell ablation enhances the capacity of regulatory T cells to delay viral elimination in Theiler's murine encephalomyelitis.

Theiler's murine encephalomyelitis (TME) of susceptible mouse strains is a commonly used infectious animal model for multiple sclerosis. The study aim was to test the hypothesis whether cytotoxic T cell responses account for the limited impact of regulatory T cells on antiviral immunity in TME virus-induced demyelinating disease (TMEV-IDD) resistant C57BL/6 mice. TME virus-infected C57BL/6 mice were treated with (i) interleukin-2/-anti-interleukin-2-antibody-complexes to expand regulatory T cells ("Treg-expansion"), (ii) anti-CD8-antibodies to deplete cytotoxic T cells ("CD8-depletion") or (iii) with a combination of Treg-expansion and CD8-depletion ("combined treatment") prior to infection. Results showed that "combined treatment", but neither sole "Treg-expansion" nor "CD8-depletion," leads to sustained hippocampal infection and virus spread to the spinal cord in C57BL/6 mice. Prolonged infection reduces myelin basic protein expression in the spinal cord together with increased accumulation of β-amyloid precursor protein in axons, characteristic of myelin loss and axonal damage, respectively. Chronic spinal cord infection upon "combined treatment" was also associated with increased T and B cell recruitment, accumulation of CD107b+ microglia/macrophages and enhanced mRNA expression of interleukin (IL)-1α, IL-10 and tumor necrosis factor α. In conclusion, data revealed that the suppressive capacity of Treg on viral elimination is efficiently boosted by CD8-depletion, which renders C57BL/6 mice susceptible to develop chronic neuroinfection and TMEV-IDD.

Engagement of TLR4 with MAM superantigen promotes HMGB1-mediated induction of IRF7 and IFNα in synoviocytes of a mouse model of human RA

Abstract Mycoplasma arthritidis mitogen (MAM), a potent superantigen (SAg) secreted by M. arthritidis, is known to contribute to arthritis in mouse models of human rheumatoid arthritis (RA). Type I interferons (IFNs) are known to play an important role in RA. IFN gene transcription is activated by IFN-regulatory factors (IRFs) in response to innate immune recognition. We previously demonstrated that mouse strains with differing expression of the innate immune receptor TLR4 or/and TLR2 differ in their response to MAM. In this study, we investigated if MAM, or MAM with an autoantigen collagen II, can stimulate synovial fibroblasts (SF) to mount inflammatory responses in a mouse arthritis model. We found that in vitro stimulation of naïve SF with MAM in an arthritis susceptible mouse strain greatly increased level of IRF7 and IFNα. HMGB1, a heat-shock stress protein was also detected to produce in the cell culture of MAM-stimulated SF. In vivo studies showed mice injected with CII and MAM developed severe arthritis and exhibited a high HMGB1 level. An increased HMGB1 level was linked to the upregulation of the intracellular IRF7 and IFNα, and IRF7 was effectively inhibited by an anti-HMGB1 treatment, suggesting HMGB1 dependence. This led to the reduction of inflammatory mediators IL-6 and MMPs in inflamed joints of arthritis mice. Thus, our results suggest that MAM is capable of selecting the SF for local joint inflammation by promoting HMGB1 and IRF7 following interaction with TLR4. Our findings clearly demonstrates microbial agents, such as MAM SAg, can modify host tissue components, such as CII and stimulate synoviocytes, thus promoting local joint inflammation in autoimmune arthritis.

The balance between Treg and TH17 cells: CD11b and interleukin-6.

One of the gold standards for animal models of rheumatoid arthritis is the murine collagen-induced arthritis model. Native type II collagen together with CFA is injected into susceptible mouse strains. Unfortunately, only mice with H-2q or H-2r MHC haplotypes are susceptible, making the widely used C57BL/6 mouse strain, which carries the H-2b haplotype, resistant against the disease. In this issue of the European Journal of Immunology, Stevanin etal. [Eur. J. Immunol. 2017. 47: 637-645] now convincingly show that although WT C57BL/6 mice are resistant to collagen-induced arthritis, mice with a homozygous deletion of CD11b on the same genetic background are fully susceptible in this important animal model of rheumatoid arthritis. They clearly demonstrate that the injection of type II collagen together with CFA leads to early onset of the disease with high incidence and with sustained severity. The authors further characterize this disease with an increase of leukocyte infiltration and enhanced TH17 differentiation.

Host Genetic Background Strongly Affects Pulmonary microRNA Expression before and during Influenza A Virus Infection.

Expression of host microRNAs (miRNAs) changes markedly during influenza A virus (IAV) infection of natural and adaptive hosts, but their role in genetically determined host susceptibility to IAV infection has not been explored. We, therefore, compared pulmonary miRNA expression during IAV infection in two inbred mouse strains with differential susceptibility to IAV infection. miRNA expression profiles were determined in lungs of the more susceptible strain DBA/2J and the less susceptible strain C57BL/6J within 120 h post infection (hpi) with IAV (H1N1) PR8. Even the miRNomes of uninfected lungs differed substantially between the two strains. After a period of relative quiescence, major miRNome reprogramming was detected in both strains by 48 hpi and increased through 120 hpi. Distinct groups of miRNAs regulated by IAV infection could be defined: (1) miRNAs (n = 39) whose expression correlated with hemagglutinin (HA) mRNA expression and represented the general response to IAV infection independent of host genetic background; (2) miRNAs (n = 20) whose expression correlated with HA mRNA expression but differed between the two strains; and (3) remarkably, miR-147-3p, miR-208b-3p, miR-3096a-5p, miR-3069b-3p, and the miR-467 family, whose abundance even in uninfected lungs differentiated nearly perfectly (area under the ROC curve > 0.99) between the two strains throughout the time course, suggesting a particularly strong association with the differential susceptibility of the two mouse strains. Expression of subsets of miRNAs correlated significantly with peripheral blood granulocyte and monocyte numbers, particularly in DBA/2J mice; miR-223-3p, miR-142-3p, and miR-20b-5p correlated most positively with these cell types in both mouse strains. Higher abundance of antiapoptotic (e.g., miR-467 family) and lower abundance of proapoptotic miRNAs (e.g., miR-34 family) and those regulating the PI3K-Akt pathway (e.g., miR-31-5p) were associated with the more susceptible DBA/2J strain. Substantial differences in pulmonary miRNA expression between the two differentially susceptible mouse strains were evident even before infection, but evolved further throughout infection and could in part be attributed to differences in peripheral blood leukocyte populations. Thus, pulmonary miRNA expression both before and during IAV infection is in part determined genetically and contributes to susceptibility to IAV infection in this murine host, and likely in humans.

Matrix Metalloproteinase Activity in Infections by an Encephalitic Virus, Mouse Adenovirus Type 1.

Mouse adenovirus type 1 (MAV-1) infection causes encephalitis in susceptible strains of mice and alters the permeability of infected brains to small molecules, which indicates disruption of the blood-brain barrier (BBB). Under pathological conditions, matrix metalloproteinases (MMPs) can disrupt the BBB through their proteolytic activity on basement membrane and tight junction proteins. We examined whether MAV-1 infection alters MMP activity in vivo and in vitro Infected MAV-1-susceptible SJL mice had higher MMP2 and MMP9 activity in brains, measured by gelatin zymography, than mock-infected mice. Infected MAV-1-resistant BALB/c mice had MMP activity levels equivalent to those in mock infection. Primary SJL mouse brain endothelial cells (a target of MAV-1 in vivo) infected ex vivo with MAV-1 had no difference in activities of secreted MMP2 and MMP9 from mock cells. We show for the first time that astrocytes and microglia are also infected in vivo by MAV-1. Infected mixed primary cultures of astrocytes and microglia had higher levels of MMP2 and MMP9 activity than mock-infected cells. These results indicate that increased MMP activity in the brains of MAV-1-infected susceptible mice may be due to MMP activity produced by endothelial cells, astrocytes, and microglia, which in turn may contribute to BBB disruption and encephalitis in susceptible mice.IMPORTANCE RNA and DNA viruses can cause encephalitis; in some cases, this is accompanied by MMP-mediated disruption of the BBB. Activated MMPs degrade extracellular matrix and cleave tight-junction proteins and cytokines, modulating their functions. MAV-1 infection of susceptible mice is a tractable small-animal model for encephalitis, and the virus causes disruption of the BBB. We showed that MAV-1 infection increases enzymatic activity of two key MMPs known to be secreted and activated in neuroinflammation, MMP2 and MMP9, in brains of susceptible mice. MAV-1 infects endothelial cells, astrocytes, and microglia, cell types in the neurovascular unit that can secrete MMPs. Ex vivo MAV-1 infection of these cell types caused higher MMP activity than mock infection, suggesting that they may contribute to the higher MMP activity seen in vivo To our knowledge, this provides the first evidence of an encephalitic DNA virus in its natural host causing increased MMP activity in brains.

Comparison of Host Gene Expression Profiles in Spleen Tissues of Genetically Susceptible and Resistant Mice during ECTV Infection.

Ectromelia virus (ECTV), the causative agent of mousepox, has emerged as a valuable model for investigating the host-Orthopoxvirus relationship as it relates to pathogenesis and the immune response. ECTV is a mouse-specific virus and causes high mortality in susceptible mice strains, including BALB/c and C3H, whereas C57BL/6 and 129 strains are resistant to the disease. To understand the host genetic factors in different mouse strains during the ECTV infection, we carried out a microarray analysis of spleen tissues derived from BALB/c and C57BL/6 mice, respectively, at 3 and 10 days after ECTV infection. Differential Expression of Genes (DEGs) analyses revealed distinct differences in the gene profiles of susceptible and resistant mice. The susceptible BALB/c mice generated more DEGs than the resistant C57BL/6 mice. Additionally, gene ontology and KEGG pathway analysis showed the DEGs of susceptible mice were involved in innate immunity, apoptosis, metabolism, and cancer-related pathways, while the DEGs of resistant mice were largely involved in MAPK signaling and leukocyte transendothelial migration. Furthermore, the BALB/c mice showed a strong induction of interferon-induced genes, which, however, were weaker in the C57BL/6 mice. Collectively, the differential transcriptome profiles of susceptible and resistant mouse strains with ECTV infection will be crucial for further uncovering the molecular mechanisms of the host-Orthopoxvirus interaction.

Admixing of MPTP-Resistant and Susceptible Mice Strains Augments Nigrostriatal Neuronal Correlates to Resist MPTP-Induced Neurodegeneration.

Disease genetics in admixed populations like Hispanic-Americans, African-Americans, etc. are gaining importance due to high disease burden in them. Furthermore, epidemiological studies conclusively prove ethnicity-based differential prevalence of Parkinson's disease (PD), since the American-Caucasians are more susceptible than Asian-Indians and Africans. Contradictorily, Anglo-Indians, an admixture of Europeans and Asian-Indians are five-times less susceptible than Indians. We evaluated the neural basis of this phenomenon using the cytomorphological features of susceptibility to nigrostriatal neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The nigral dopaminergic neuronal numbers, their size and tyrosine hydroxylase (TH), PitX3 and Nurr1 expression were compared in MPTP-susceptible C57BL/6J mice, MPTP-resistant CD-1 mice and their crossbreds using stereology, morphometry and densitometry. Apoptotic index was evaluated by TUNEL-assay and caspase-3 expression. Striatal volume, TH and glial derived neurotrophic factor (GDNF) expression were studied. The normal CD-1 and crossbreds had significantly more, although smaller, nigral dopaminergic neurons than C57BL/6J, and a larger striatum. The crossbreds had higher TH, Nurr1 and PitX3 levels. MPTP administration caused loss of ~50-60% nigral dopaminergic neurons in C57BL/6J and ~15% in CD-1, but none in crossbreds. MPTP-induced cellular shrinkage in C57BL/6J was contrasted by nuclear enlargement without somal alterations in resistant strains. MPTP lowered the striatal TH and GDNF in C57BL/6J. Elevated striatal GDNF in CD-1 and crossbreds could be of compensatory nature and complemented the reduced nigral caspase-3 expression to attenuate and/or block apoptosis. Similar neural correlates of resilience are envisaged in the Anglo-Indian population. Thus, we present the core neuroanatomical features of resilience against PD and evidence for ethnicity-based differential prevalence.

Deficiency of the adaptor protein SLy1 results in a natural killer cell ribosomopathy affecting tumor clearance

ABSTRACTIndividuals with robust natural killer (NK) cell function incur lower rates of malignancies. To expand our understanding of genetic factors contributing to this phenomenon, we analyzed NK cells from cancer resistant and susceptible strains of mice. We identified a correlation between NK levels of the X-chromosome-located adaptor protein SLy1 and immunologic susceptibility to cancer. Unlike the case for T or B lymphocytes, where SLy1 shuttles between the cytoplasm and nucleus to facilitate signal transduction, in NK cells SLy1 functions as a ribosomal protein and is located solely in the cytoplasm. In its absence, ribosomal instability results in p53-mediated NK cell senescence and decreased clearance of malignancies. NK defects are reversible under inflammatory conditions and viral clearance is not impacted by SLy1 deficiency. Our work defines a previously unappreciated X-linked ribosomopathy that results in a specific and subtle NK cell dysfunction leading to immunologic susceptibility to cancer.

Differences in susceptibility of mouse strains to tetrodotoxin

The mouse bioassay for tetrodotoxin has been used for many years in Japan. To the best of our knowledge, however, there have only been a few reports that have specifically investigated differences in susceptibility to tetrodotoxin among mouse strains. In this study, we investigated the response of various mouse strains to tetrodotoxin. Tetrodotoxin solution was injected intraperitoneally into male mice of 5 inbred strains (A/J, BALB/c, C3H/He, C57BL/6, and DBA/2) and male and female mice of 2 non-inbred strains (ddY and ICR). Significant differences in susceptibility to tetrodotoxin were found among the mouse strains tested. In comparison to the ddY male mice, which are designated to be used in the Japanese reference method, the 5 inbred strains of mice tested were significantly more resistant to tetrodotoxin. However, no significant differences in tetrodotoxin susceptibility were observed between ddY male and female mice or between ddY male mice and ICR male and female mice. These results indicate that the users of the mouse bioassay should pay attention to differences in mouse strain in susceptibility to tetrodotoxin.

IL-15 complex-stimulated NK cells protect mice from cerebral malaria

Abstract Cerebral malaria (CM) is one of the most lethal complications of Plasmodium falciparum infection, responsible for a large fraction of the nearly one million malaria-related deaths annually. Infection of susceptible mouse strains such as C57BL/6 with Plasmodium berghei ANKA (PbA) induces a fatal neurological syndrome from 6–10 days post-infection (dpi) resulting from CD8 T cell-mediated damage to the CNS. We found that treatment of C57BL/6 mice with interleukin (IL)-15 complexes (IL-15C; IL-15 bound to an IL-15Rα-Fc fusion protein) prevented the development of PbA-induced CM. Rescue from CM was not associated with reduced parasitemia at 5 dpi. Instead, IL-15C treatment resulted in reduced CD8 T cell activation in the brain at 6 dpi and reduced blood brain barrier breakdown. In addition, adoptive transfer of IL-15C-stimulated natural killer (NK) cells (but not CD8+ T cells) was sufficient to prevent CM. IL-15C and similar complexes formed with IL-2 (IL-2C; IL-2 bound to the anti-IL-2 S4B6 antibody) both cause robust expansion and activation of NK cells but, unexpectedly, NK cells from mice treated with IL-2C failed to protect against CM. Comparative RNAseq analysis of IL-15C and IL-2C-treated NK cells identified novel gene expression patterns, demonstrating previously unappreciated differences between these cytokine complex signaling cascades in NK cells; the functional significance of these differences is being assessed. These data indicate that NK cells – which are typically involved in promoting inflammatory responses – can restrain damaging immune responses, and that differences between the activation of NK cells by IL-2C and IL-15C regulates their capacity to control the inflammatory response to blood stage malaria infection.

A monoclonal natural human IgM protects axons in the absence of remyelination.

BackgroundWhereas demyelination underlies early neurological symptoms in multiple sclerosis (MS), axonal damage is considered critical for permanent chronic deficits. Intracerebral infection of susceptible mouse strains with Theiler’s murine encephalomyelitis virus (TMEV) results in chronic induced demyelinating disease (TMEV-IDD) with progressive axonal loss and neurologic dysfunction similar to progressive forms of MS. We previously reported that treatment of chronic TMEV-IDD mice with a neurite outgrowth-promoting natural human antibody, HIgM12, improved brainstem NAA concentrations and preserved functional motor activity. In order to translate this antibody toward clinical trial, we generated a fully human recombinant form of HIgM12, rHIgM12, determined the optimal in vivo dose for functional improvement in TMEV-IDD, and evaluated the functional preservation of descending spinal cord axons by retrograde labeling.FindingsSJL/J mice at 45 to 90 days post infection (dpi) were studied. A single intraperitoneal dose of 0.25 mg/kg of rHIgM12 per mouse is sufficient to preserve motor function in TMEV-IDD. The optimal dose was 10 mg/kg. rHIgM12 treatment protected the functional transport in spinal cord axons and led to 40 % more Fluoro-Gold-labeled brainstem neurons in retrograde transport studies. This suggests that axons are not only present but also functionally competent. rHIgM12-treated mice also contained more mid-thoracic (T6) spinal cord axons than controls.ConclusionsThis study confirms that a fully human recombinant neurite outgrowth-promoting monoclonal IgM is therapeutic in a model of progressive MS using multiple reparative readouts. The minimum effective dose is similar to that of a remyelination-promoting monoclonal human IgM discovered by our group that is presently in clinical trials for MS.

P-135 YI IL-22 Promotes Helicobacter Hepaticus-Induced H2AX Phosphorylation and Dysbiosis in the Large Bowel

Interleukin-22 (IL-22) plays an essential role in the innate immunity to enteric pathogens, at least in part through induction of anti-microbial peptides (AMP). Helicobacter hepaticus (Hh) induces chronic colitis and colon cancer in susceptible mouse strains. Previous studies have described high levels of IL-22 mRNA within the lower bowel of Rag2−/− mice chronically infected with Hh. However, the role of IL-22 in modulating the early innate immune response to Hh infection has not been fully explored. Female and male 129S6/SvEvTac-Rag2tm1Fwa mice were infected with H. hepaticus and the inflammatory response in the lower bowel examined 2 weeks later. Inflammation was evaluated by scoring of H&E stained slides of the cecum and colon, and immune cell populations within the intestine were evaluated using flow cytometry. Pro-inflammatory cytokine expression within the lower bowel was evaluated by quantitative-PCR, and DNA damage within colonic epithelial was assessed by immunostaining for γH2AX, a marker of DNA double-stranded breaks. To evaluate the role of IL-22 in this system, mice were treated with anti-IL-22 antibody following Hh infection. The influence of Hh infection and IL-22-depletion on the colonic microbiome was evaluated by sequencing of bacterial 16S rRNA genes. We found that Hh infection rapidly induced inflammation that was significantly more severe in the cecocolic junction than either the proximal or distal colon, associated with increases in the percentages of CD45+CD11b+CD64+Ly6c+MHCII+ inflammatory monocytes and Ly6G+Ly6c+ neutrophils, as well as increases in absolute numbers of ThyHigh type-3 innate lymphoid cells (ILCs). Infection was associated with increase expression of IL-22 and AMP RegIIIβ and RegIIIγ, and AMP expression was inhibited by treatment with an anti-IL-22 antibody. Depletion of IL-22 did not influence the severity of inflammation within the cecum, although it did mildly reduce inflammation in the colon. Unexpectedly, mice infected with Hh exhibited accumulation of γH2AX+ intestinal crypt epithelial cells suggesting that Hh infection may acutely induce DNA damage, and remarkably γH2AX staining was inhibited by depletion of IL-22. Interestingly, Hh infection induced dysbiosis characterized by reduced species diversity and expansion of the phylum Proteobacteria, which was partially reversed by depletion of IL-22. These results indicated that IL-22 has a limited role in regulating Hh-induced inflammation within the cecum. However, the observation that Hh infection acutely induces γH2AX staining which is inhibited by depletion of IL-22, raises the possibility that IL-22 mediates the accumulation of epithelial cells that contain damaged DNA following Hh infection. These observations could have important implications for understanding of the relationship between inflammation, dysbiosis, and neoplasia within the lower bowel.

Evidence for Persistence of Ectromelia Virus in Inbred Mice, Recrudescence Following Immunosuppression and Transmission to Naïve Mice.

Orthopoxviruses (OPV), including variola, vaccinia, monkeypox, cowpox and ectromelia viruses cause acute infections in their hosts. With the exception of variola virus (VARV), the etiological agent of smallpox, other OPV have been reported to persist in a variety of animal species following natural or experimental infection. Despite the implications and significance for the ecology and epidemiology of diseases these viruses cause, those reports have never been thoroughly investigated. We used the mouse pathogen ectromelia virus (ECTV), the agent of mousepox and a close relative of VARV to investigate virus persistence in inbred mice. We provide evidence that ECTV causes a persistent infection in some susceptible strains of mice in which low levels of virus genomes were detected in various tissues late in infection. The bone marrow (BM) and blood appeared to be key sites of persistence. Contemporaneous with virus persistence, antiviral CD8 T cell responses were demonstrable over the entire 25-week study period, with a change in the immunodominance hierarchy evident during the first 3 weeks. Some virus-encoded host response modifiers were found to modulate virus persistence whereas host genes encoded by the NKC and MHC class I reduced the potential for persistence. When susceptible strains of mice that had apparently recovered from infection were subjected to sustained immunosuppression with cyclophosphamide (CTX), animals succumbed to mousepox with high titers of infectious virus in various organs. CTX treated index mice transmitted virus to, and caused disease in, co-housed naïve mice. The most surprising but significant finding was that immunosuppression of disease-resistant C57BL/6 mice several weeks after recovery from primary infection generated high titers of virus in multiple tissues. Resistant mice showed no evidence of a persistent infection. This is the strongest evidence that ECTV can persist in inbred mice, regardless of their resistance status.

Time-Dependent Progression of Demyelination and Axonal Pathology in MP4-Induced Experimental Autoimmune Encephalomyelitis.

BackgroundMultiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by inflammation, demyelination and axonal pathology. Myelin basic protein/proteolipid protein (MBP-PLP) fusion protein MP4 is capable of inducing chronic experimental autoimmune encephalomyelitis (EAE) in susceptible mouse strains mirroring diverse histopathological and immunological hallmarks of MS. Limited availability of human tissue underscores the importance of animal models to study the pathology of MS.MethodsTwenty-two female C57BL/6 (B6) mice were immunized with MP4 and the clinical development of experimental autoimmune encephalomyelitis (EAE) was observed. Methylene blue-stained semi-thin and ultra-thin sections of the lumbar spinal cord were assessed at the peak of acute EAE, three months (chronic EAE) and six months after onset of EAE (long-term EAE). The extent of lesional area and inflammation were analyzed in semi-thin sections on a light microscopic level. The magnitude of demyelination and axonal damage were determined using electron microscopy. Emphasis was put on the ventrolateral tract (VLT) of the spinal cord.ResultsB6 mice demonstrated increasing demyelination and severe axonal pathology in the course of MP4-induced EAE. In addition, mitochondrial swelling and a decrease in the nearest neighbor neurofilament distance (NNND) as early signs of axonal damage were evident with the onset of EAE. In semi-thin sections we observed the maximum of lesional area in the chronic state of EAE while inflammation was found to a similar extent in acute and chronic EAE. In contrast to the well-established myelin oligodendrocyte glycoprotein (MOG) model, disease stages of MP4-induced EAE could not be distinguished by assessing the extent of parenchymal edema or the grade of inflammation.ConclusionsOur results complement our previous ultrastructural studies of B6 EAE models and suggest that B6 mice immunized with different antigens constitute useful instruments to study the diverse histopathological aspects of MS.

Interferon-stimulated genes-essential antiviral effectors implicated in resistance to Theiler's virus-induced demyelinating disease.

BackgroundExperimental infection of mice with Theiler’s murine encephalomyelitis virus (TMEV) is used as an animal model of human multiple sclerosis. TMEV persists in susceptible mouse strains and causes a biphasic disease consisting of acute polioencephalomyelitis and chronic demyelinating leukomyelitis. In contrast, resistant mice eliminate the virus within 2 to 4 weeks, which seems to be based on a strong antiviral innate immune response including the activation of the type I interferon (IFN) pathway. Several interferon-stimulated genes (ISGs) such as IFN-stimulated protein of 15 kDa (ISG15), protein kinase R (PKR), and 2′5′-oligoadenylate synthetase (OAS) function as antiviral effectors and might contribute to virus elimination. Nevertheless, detailed investigations of the type I IFN pathway during TMEV-induced demyelinating disease (TMEV-IDD) are lacking.MethodsThe present study evaluated microarray data of the spinal cord obtained from susceptible SJL/J mice after TMEV infection focusing on IFN-related genes. Moreover, ISG gene and protein expression was determined in mock- and TMEV-infected SJL/J mice and compared to its expression in resistant C57BL/6 mice using real- time PCR, immunohistochemistry, and immunofluorescence.ResultsInterestingly, despite of increased ISG gene expression during TMEV-IDD, ISG protein expression was impaired in SJL/J mice and mainly restricted to demyelinated lesions. In contrast, high ISG protein levels were found in spinal cord gray and white matter of C57BL/6 compared to SJL/J mice in the acute and chronic phase of TMEV-IDD. In both mouse strains, ISG15 was mainly found in astrocytes and endothelial cells, whereas PKR was predominantly expressed by microglia/macrophages, oligodendrocytes, and neurons. Only few cells were immunopositive for OAS proteins.ConclusionsHigh levels of antiviral ISG15 and PKR proteins in the spinal cord of C57BL/6 mice might block virus replication and play an important role in the resistance to TMEV-IDD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-015-0462-x) contains supplementary material, which is available to authorized users.

Autoimmunity: The good, the bad, and the ugly.

Some readers may remember, as I do, that we were taught to consider autoimmunity as the result of an imbalance of the immune system, often with bad or ugly (translation: very bad) consequences, including refractoriness to treatment, irreversible deficits, or death. We now know that there is protective (good) autoimmunity that can prevent the development of disease, at least in animal models. Indeed, an article by Ortega et al.1 shows that, depending on the type of antigen and mouse strain, it is possible to generate CD8+ T cells that suppress the development of experimental autoimmune encephalitis (EAE). The authors had previously reported this protective effect in C57BL/6 mice showing that MOG35-55-specific CD8+ T cells suppressed EAE development. In the current article, they demonstrate that using other myelin peptides, such as PLP178-191 and other susceptible mouse strains (SJL), the generated myelin-specific CD8+ T cells were able to suppress disease. The disease-preventing function of these cells was dependent on the specific cognate myelin antigen. Moreover, the generation of the T cells depended on the presence of both CD4+ and CD8+ T-cell epitopes in the antigen used to immunize the mice, and did not appear to be affected by thymic selection. Findings from these models improve our understanding of autoregulatory CD8+ T cells, and have implications for the development of novel therapies for immune-mediated diseases. In contrast, most common treatment approaches to autoimmune disorders use drugs that rebalance the abnormal immune response toward suppressive mechanisms. Molnarfi et al.2 show in another article in this issue that glatiramer acetate inhibits the type I interferon (IFN) pathway in monocyte type II (M2) polarization.

Autoregulatory CD8 T cells depend on cognate antigen recognition and CD4/CD8 myelin determinants.

Objective:To determine the antigenic determinants and specific molecular requirements for the generation of autoregulatory neuroantigen-specific CD8+ T cells in models of multiple sclerosis (MS).Methods:We have previously shown that MOG35-55-specific CD8+ T cells suppress experimental autoimmune encephalomyelitis (EAE) in the C57BL/6 model. In this study, we utilized multiple models of EAE to assess the ability to generate autoregulatory CD8+ T cells.Results:We demonstrate that alternative myelin peptides (PLP178-191) and other susceptible mouse strains (SJL) generated myelin-specific CD8+ T cells, which were fully capable of suppressing disease. The disease-ameliorating function of these cells was dependent on the specific cognate myelin antigen. Generation of these autoregulatory CD8+ T cells was not affected by thymic selection, but was dependent on the presence of both CD4+ and CD8+ T-cell epitopes in the immunizing encephalitogenic antigen.Conclusions:These studies show that the generation of autoregulatory CD8+ T cells is a more generalized, antigen-specific phenomenon across multiple neuroantigens and mouse strains, with significant implications in understanding disease regulation.

Mouse model of ulcerative colitis using trinitrobenzene sulfonic acid

<p>Animal model of intestinal inflammation is of paramount significance that aids in discerning the pathologies underlying ulcerative colitis and Crohn’s disease, the two clinical presentations of inflammatory bowel disease. The 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis model represents one such intestinal inflammation-prototype that is generated in susceptible strains of mice through intra-rectal instillation of compound TNBS. In this paper, we demonstrate the experimental induction of TNBS-mediated colitis in a susceptible strain of ICR mice. This can be done by the following steps: a) acclimation, b) induction and c) observation. TNBS-mouse model provides the information in shortest possible time and simultaneously represents a cost effective and highly reproducible model method of studying the pathogenesis of inflammatory bowel disease.</p><p><strong>Video Clips</strong></p><p><a href="https://youtube.com/v/6MsuIGzH3uA">Acclimation and induction of TNBS</a>: 4.5 min</p><p><a href="https://youtube.com/v/ya66SNwoVag">Observation and drug administration</a>: 1.5 min</p>

A vaccine formulated with the major outer membrane protein can protect C3H/HeN, a highly susceptible strain of mice, from a Chlamydia muridarum genital challenge.

C3H/HeN female mice were vaccinated with native Chlamydia muridarum major outer membrane protein (MOMP), using Montanide+CpG or Alum+CpG as adjuvants. Negative control groups were immunized with ovalbumin (OVA) and the same adjuvants. As positive control, mice were inoculated intranasally with live Chlamydia. Mice were challenged in the ovarian bursa with 10(5) C.muridarum inclusion forming units. Six weeks after the genital challenge the animals were caged with male mice and monitored for pregnancy. Mice vaccinated with MOMP+Montanide+CpG developed high levels of C.muridarum-specific antibodies, with a high IgG2a/IgG1 ratio and neutralizing titres. Animals immunized using Alum+CpG had low antibody levels. Cellular immune responses were significantly higher in mice vaccinated with MOMP and Montanide+CpG, but not with Alum+CpG, when compared with negative controls. Following the genital challenge, only 20% (4/20) of mice vaccinated with MOMP+CpG+Montanide had positive vaginal cultures whereas 100% (9/9) of mice immunized with MOMP+CpG+Alum had positive cultures. Of the positive control animals inoculated with live Chlamydia only 15% (3/20) had positive vaginal cultures. In contrast, 100% (20/20) of mice immunized with OVA+CpG+Montanide, or minimal essential medium, had positive cultures. Following mating, 80% (16/20) of mice vaccinated with MOMP+CpG+Montanide, and 85% (17/20) of animals inoculated intranasally with live C.muridarum carried embryos in both uterine horns. No protection against infertility was observed in mice immunized with MOMP and CpG+Alum or OVA. In conclusion, this is the first time that a subunit vaccine has been shown to elicit a protective immune response in the highly susceptible C3H/HeN strain of mice against an upper genital challenge.

Investigation of the relationship between the onset of arthritis and uveitis in genetically predisposed SKG mice.

IntroductionSystemic rheumatic conditions are often accompanied by intraocular inflammatory disease (termed uveitis). Despite the frequent manifestation of uveitis with arthritis, very little is understood of the underlying mechanisms that mediate the eye’s susceptibility to disease. The genetically susceptible SKG mouse strain develops arthritis that arises from an inherent mutation that disrupts T-cell antigen receptor signal transduction and thymic selection. The ensuing T-cell–mediated disease is further modulated through exposure to microbial triggers. The purpose of this study was to elucidate how a genetically determined shift in the T-cell repertoire toward self-reactive T cells that drive arthritis influences uveitis in SKG mice.MethodsSKG mice (BALB/c mice that harbor the W163C point mutation in zeta-chain-associated protein kinase 70 [i.e., ZAP-70]) were housed under arthritis-resistant, specific pathogen–free conditions. Arthritis was induced by intraperitoneal injection with fungal glucans (zymosan or curdlan). Arthritis onset and severity were evaluated by clinical scoring, histopathology and infrared imaging within the joints. Periocular traits involving blepharoconjunctivitis were evaluated by clinical scoring and histology. Eyes were evaluated for signs of anterior uveitis using intravital videomicroscopy to document cell-trafficking responses within the iris vasculature and stroma and by histology to detect inflammatory infiltrate and tissue damage within the anterior and posterior eye segments.ResultsExposure to zymosan resulted in the predicted arthritic, sexually dimorphic phenotype in SKG mice. The eyes of SKG mice exhibited episodic intravascular cellular responses to zymosan or curdlan as indicated by significant increases in leukocyte–endothelium interactions akin to ocular vasculitis. However, despite the significant increase in early cell-trafficking responses, cellular infiltration into the iris stroma was not observed and histopathological signs indicative of a sustained uveitis were absent. Instead, eyes of SKG mice developed blepharoconjunctivitis that coincided with arthritis and exhibited sexual dimorphism.ConclusionsThis study underscores the complexity surrounding the pathogenesis of uveitis and its relationship with arthritis. The findings suggest that distinct mechanisms exist by which pathogenic autoimmune T cells target the eyes versus joints, which likely involves the environmental context but nonetheless should be taken into account in the identification and development of effective therapies for each organ.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0725-z) contains supplementary material, which is available to authorized users.