Profound reduction of mature B cell numbers, reactivities and serum lg levels in mice which simultaneously carry the XID and CD40 deficiency gense

It has been known for some time that single mutant nude or CD40T mice have apparently normal numbers of cells in the precursor compartments of bone marrow and the mature B cell compartments of the periphery. X-linked immunodeficiency (XID) mice are deficient only in some of the slgM+slgD+ B cells. We have investigated further the contributions of the xid mutation, of the T cell deficiency of nude and of the inability of CD40T B cells to cooperate with T cells in the generation of the precursor and the mature B cell compartments in mice. Double mutant XIDInu and XIDlCD4OT mice have precursor B cell compartments that are no more deficient than the single mutant XID mice. However, the peripheral B cell compartments of both XIDInu and XIDlCD40T are even more deficient than those of single mutant XID mice. While 10% of the peripheral B cells of wild-type or CD40T, one-third of XID and half of XIDInu mice turn over rapidly, as many as threequarters of those in XIDlCD40T are short-lived. Total numbers of slgM+slgD+ B cells in the spleen are at best 1615% of normal mice at 6-8 weeks of age in XID, XIDInu and XIDICD40T mice. They remain that low at 3 months of age in XIDICD40T mice, while in XID mice these peripheral B cells slowly build up in numbers with age. As expected, double mutant XIDlCD40T mice do not respond to the T-dependent antigen keyhole limpet hemocyanin. Only the responses to the T-independent type I antigen, TNP-lipopolysaccharide (LPS), appear to be normal. In vitro, their splenic B cells respond poorly to LPS or to IgM-specific antibody in either the absence or presence of cytokines. Most notably, serum IgM, lgG2b and lgG3 levels are severely depressed, while IgG1, lgG2a and IgA levels are <I0 pglml. The results suggest a model of mature B cell development in which the peripheral, mature B cell compartments are generated in two parallel, not tandemly organized pathways. They could be selected and/or stimulated at the transition from immature to mature B cells: in btk controlled or in CD40 controlled way

Partial suppression of M1 microglia by Janus kinase 2 inhibitor does not protect against neurodegeneration in animal models of amyotrophic lateral sclerosis

BACKGROUND: Accumulating evidence has shown that the inflammatory process participates in the pathogenesis of amyotrophic lateral sclerosis (ALS), suggesting a therapeutic potential of anti-inflammatory agents. Janus kinase 2 (JAK2), one of the key molecules in inflammation, transduces signals downstream of various inflammatory cytokines, and some Janus kinase inhibitors have already been clinically applied to the treatment of inflammatory diseases. However, the efficacy of JAK2 inhibitors in treatment of ALS remains to be demonstrated. In this study, we examined the role of JAK2 in ALS by administering a selective JAK2 inhibitor, R723, to an animal model of ALS (mSOD1(G93A) mice). FINDINGS: Orally administered R723 had sufficient access to spinal cord tissue of mSOD1(G93A) mice and significantly reduced the number of Ly6c positive blood monocytes, as well as the expression levels of IFN-γ and nitric oxide synthase 2, inducible (iNOS) in the spinal cord tissue. R723 treatment did not alter the expression levels of Il-1β, Il-6, TNF, and NADPH oxidase 2 (NOX2), and suppressed the expression of Retnla, which is one of the markers of neuroprotective M2 microglia. As a result, R723 did not alter disease progression or survival of mSOD1(G93A) mice. CONCLUSIONS: JAK2 inhibitor was not effective against ALS symptoms in mSOD1(G93A) mice, irrespective of suppression in several inflammatory molecules. Simultaneous suppression of anti-inflammatory microglia with a failure to inhibit critical other inflammatory molecules might explain this result. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12974-014-0179-2) contains supplementary material, which is available to authorized users

Accelerated tumor growth in mice deficient in DNAM-1 receptor

Since the identification of ligands for human and mouse DNAM-1, emerging evidence has suggested that DNAM-1 plays an important role in the T cell– and natural killer (NK) cell–mediated recognition and lysis of tumor cells. However, it remains undetermined whether DNAM-1 is involved in tumor immune surveillance in vivo. We addressed this question by using DNAM-1–deficient mice. DNAM-1–deficient cytotoxic T lymphocyte (CTL) and NK cells showed significantly less cytotoxic activity against DNAM-1 ligand-expressing tumors in vitro than wild-type (WT) cells. The methylcholanthrene (MCA)-induced fibrosarcoma cell line Meth A expressed the DNAM-1 ligand CD155, and DNAM-1–deficient mice showed increased tumor development and mortality after transplantation of Meth A cells. Moreover, the DNAM-1–deficient mice developed significantly more DNAM-1 ligand-expressing fibrosarcoma and papilloma cells in response to the chemical carcinogens MCA and 7,12-dimethylbenz[a]anthracene (DMBA), respectively, than did WT mice. These results indicate that DNAM-1 plays an important role in immune surveillance of tumor development

The immunoreceptor adapter protein DAP12 suppresses B lymphocyte–driven adaptive immune responses

Human and mouse B cells lacking functional DAP12 are hyperresponsive, and DAP12 works with MAIR-II (CD300d) to negatively regulate B cell activity

LMP1 Transmembrane Domain 1 and 2 (TM1-2) FWLY Mediates Intermolecular Interactions with TM3-6 To Activate NF-κB

The Epstein-Barr virus oncoprotein LMP1 has six transmembrane domains (TMs) that enable intermolecular aggregation and constitutive signaling through two C-terminal cytosolic domains. Expression of both TMs 1 and 2 without the C terminus (TM1-2ΔC) and TMs 3 to 6 fused to the C terminus (TM3-6) results in partial association, which is substantially decreased by TM1 F(38)WLY(41) mutation to A(38)ALA(41). We now investigate whether TM1-2ΔC can functionally interact with TM3-6. TM1-2ΔC induced TM3-6 to mediate NF-κB activation at 59% of LMP1 levels, and the effect was dependent on TM1-2 F(38)WLY(41). TM1-2ΔC even induced TM3-4 C terminus-mediated NF-κB activation to 44% of LMP1 levels. Surprisingly, this effect was TM1 F(38)WLY(41) independent, indicative of a role for TMs 5 and 6 in TM1 F(38)WLY(41) effects. TM3 W(98) was also important for TM1-2ΔC induction of TM3-6-mediated NF-κB activation, for association, and for TM1 F(38)WLY(41) dependence on C-terminal NF-κB activation. These data support models in which the TM1 F(38)WLY(41) effects are at least partially dependent on TM3 W(98) and a residue(s) in TMs 5 and 6

BS69 negatively regulates the canonical NF-κB activation induced by Epstein-Barr virus-derived LMP1

Epstein–Barr virus (EBV) latent membrane protein 1 (LMP1) activates NF-κB signaling pathways through the two C-terminal regions, CTAR1 and CTAR2. BS69 has previously been shown to be involved in LMP1-induced c-Jun N-terminal kinase activation through CTAR2 by interacting with tumor necrosis factor (TNFR) receptor-associated factor 6. In the present study, our manipulation of BS69 expression clearly indicates that BS69 negatively regulates LMP1-mediated NF-κB activation and up-regulates IL-6 mRNA expression and IκB degradation. Our immunoprecipitation experiments suggest that BS69 decreases complex formation between LMP1 and TNFR-associated death domain protein (TRADD)

Deleterious effects of lymphocytes at the early stage of neurodegeneration in an animal model of amyotrophic lateral sclerosis

<p>Abstract</p> <p>Background</p> <p>Non-neuronal cells, such as microglia and lymphocytes, are thought to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). Previous studies have demonstrated neuroprotective effects of lymphocytes at the end stage of ALS, partly through induction of alternatively activated microglia (M2 microglia), which are neuroprotective. In this study, we investigated the role of lymphocytes in the early stage of the disease using an animal model of inherited ALS.</p> <p>Methods</p> <p>We established a transgenic mouse line overexpressing the familial ALS-associated G93A-SOD1 mutation (harboring a single amino acid substitution of glycine to alanine at codon 93) with depletion of the Rag2 gene (mSOD1/RAG2-/- mice), an animal model of inherited ALS lacking mature lymphocytes. Body weights, clinical scores and motor performance (hanging wire test) of mSOD1/RAG2-/- mice were compared to those of mutant human SOD1 transgenic mice (mSOD1/RAG2+/+ mice). Activation of glial cells in the spinal cords of these mice was determined immunohistochemically, and the expression of mRNA for various inflammatory and anti-inflammatory molecules was evaluated.</p> <p>Results</p> <p>Clinical onset in mSOD1/RAG2-/- mice was significantly delayed, and the number of lectin-positive cells in spinal cord was increased at the early stage of disease when compared to mSOD1/RAG2+/+ mice. Quantitative RT-PCR confirmed that mRNA for Ym1, an M2 microglial-related molecule, was significantly increased in mSOD1/RAG2-/- mouse spinal cords at the early disease stage.</p> <p>Conclusions</p> <p>Compared with mSOD1/RAG2+/+ mice, mSOD1/RAG2-/- mice displayed delayed onset and increased M2 microglial activation at the early stage of disease. Thus, lymphocytes at the early pathological phase of ALS display a deleterious effect via inhibition of M2 microglial activation.</p

Caspase-dependent cleavage regulates protein levels of Epstein-Barr virus-derived latent membrane protein 1

Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP1) plays pathogenic roles in EBV-related diseases. Thus, host cells employ several mechanisms to regulate LMP1 functions, and we previously reported possible regulation by signal transducing adaptor protein-2 as well as BS69. Here, we found that caspase-3 mainly degraded LMP1 proteins in HeLa cells, leading to decreased NF-kappa B and STAT3 activation. Caspase-3 cleaved the consensus DNTD sequences in the CTAR3 region of LMP1. Of importance, LMP1 expression strongly enhanced caspase-3 activity. Taken together, the reduction of LMP1 protein levels by caspases is likely to be a newly identified host defense against EBV infection