Autoantibodies against lamin C, NA14 and CK15 in primary vasculitides or autoimmune diseases with secondary vasculitis

OBJECTIVES

Autoantibodies may play a role in the pathogenesis of primary vasculitides (PVs) like giant cell arteritis (GCA). We recently identified 3 cytoskeletal proteins (lamin C [laC], nuclear autoantigen of 14kD [NA14] and cytokeratin 15 [CK15]) as autoantigens in GCA and postulated a frequent autoantibody response against these antigens in PVs.

METHODS

To test this hypothesis we studied a cohort of patients with PVs (n=61) and healthy individuals (n=27) for the presence of these autoantibodies using a recombinant cDNA expression library. To define their specifity for PV, we also examined patients with other autoimmune diseases such as rheumatoid arthritis (RA) and connective tissue diseases (CTD).

RESULTS

We found no statistically significant differences in autoantibody responses between patients with PV and healthy controls, although there was a trend for an association between PVs and the occurrence of antibodies against laC and CK15. However, in patients with RA (n=33) or Sjögren's syndrome (SS, n=11) with vasculitides we observed more frequently autoantibodies against NA14, laC and CK15 compared to healthy controls. In patients with systemic lupus erythematosus (SLE, n=23) autoantibodies against laC were more frequent. The presence of autoantibodies in RA, SS and SLE was associated with systemic secondary vasculitis (SSV). In RA, laC- and NA14-seropositive patients were in a more advanced disease stage than seronegative patients with more frequent extraarticular manifestations (p=0.004). In SLE laC-autoantibody-positive patients had a higher SLE activity index (p<0.001).

CONCLUSIONS

Serum autoantibodies against laC and NA14 are frequent in patients with RA and CTD and are associated with extensive disease and SSV. The potential pathogenic and prognostic role of these antibodies should be further investigated.

Primary B Lymphocytes Infected with Kaposi's Sarcoma-Associated Herpesvirus Can Be Expanded In Vitro and Are Recognized by LANA-Specific CD4+ T Cells

Kaposi's sarcoma-associated herpesvirus (KSHV) has tropism for B lymphocytes, in which it establishes latency, and can also cause lymphoproliferative disorders of these cells manifesting as primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). T cell immunity is vital for the control of KSHV infection and disease; however, few models of B lymphocyte infection exist to study immune recognition of such cells. Here, we developed a model of B lymphocyte infection with KSHV in which infected tonsillar B lymphocytes were expanded by providing mitogenic stimuli and then challenged with KSHV-specific CD4(+)T cells. The infected cells expressed viral proteins found in PELs, namely, LANA and viral IRF3 (vIRF3), albeit at lower levels, with similar patterns of gene expression for the major latency, viral interleukin 6 (vIL-6), and vIRF3 transcripts. Despite low-level expression of open reading frame 50 (ORF50), transcripts for the immune evasion genes K3 and K5 were detected, with some downregulation of cell surface-expressed CD86 and ICAM. The vast majority of infected lymphocytes expressed IgM heavy chains with Igλ light chains, recapitulating the features seen in infected cells in MCD. We assessed the ability of the infected lymphocytes to be targeted by a panel of major histocompatibility complex (MHC) class II-matched CD4(+)T cells and found that LANA-specific T cells restricted to different epitopes recognized these infected cells. Given that at least some KSHV latent antigens are thought to be poor targets for CD8(+)T cells, we suggest that CD4(+)T cells are potentially important effectors for thein vivocontrol of KSHV-infected B lymphocytes.

IMPORTANCE

KSHV establishes a latent reservoir within B lymphocytes, but few models exist to study KSHV-infected B cells other than the transformed PEL cell lines, which have likely accrued mutations during the transformation process. We developed a model of KSHV-infected primary B lymphocytes that recapitulates features seen in PEL and MCD by gene expression and cell phenotype analysis, allowing the study of T cell recognition of these cells. Challenge of KSHV-infected B cells with CD4(+)T cells specific for LANA, a protein expressed in all KSHV-infected cells and malignanciesin vivo, showed that these effectors could efficiently recognize such targets. Given that the virus expresses immune evasion genes or uses proteins with intrinsic properties, such as LANA, that minimize epitope recognition by CD8(+)T cells, CD4(+)T cell immunity to KSHV may be important for maintaining the virus-host balance.

Production and Characterization of Monoclonal Antibodies against Human Nuclear Protein FAM76B

Human FAM76B (hFAM76B) is a 39 kDa protein that contains homopolymeric histidine tracts, a targeting signal for nuclear speckles. FAM76B is highly conserved among different species, suggesting that it may play an important physiological role in normal cellular functions. However, a lack of appropriate tools has hampered study of this potentially important protein. To facilitate research into the biological function(s) of FAM76B, murine monoclonal antibodies (MAbs) against hFAM76B were generated by using purified, prokaryotically expressed hFAM76B protein. Six strains of MAbs specific for hFAM76B were obtained and characterized. The specificity of MAbs was validated by using FAM76B^-/- HEK 293 cell line. Double immunofluorescence followed by laser confocal microscopy confirmed the nuclear speckle localization of hFAM76B, and the specific domains recognized by different MAbs were further elucidated by Western blot. Due to the high conservation of protein sequences between mouse and human FAM76B, MAbs against hFAM76B were shown to react with mouse FAM76B (mFAM76B) specifically. Lastly, FAM76B was found to be expressed in the normal tissues of most human organs, though to different extents. The MAbs produced in this study should provide a useful tool for investigating the biological function(s) of FAM76B.

Role of PHLPP1 in inflammation response: Its loss contributes to gliomas development and progression

PH domain leucine-rich repeats protein phosphatase 1(PHLPP1) belongs to a novel family of Ser/Thr protein phosphatases: PHLPP serves as tumor suppressor in several cancers. However, little knowledge about the expression of PHLPP1 in human glioma tumor tissue and its role in inflammation response in glioma cells was known. Glioma samples were obtained from a total of 37 patients including 16 males and 21 females with surgical removal of the brain tumor. PHLPP1 protein and inflammatory cytokines were measured by Western blot analysis and immunohistochemistry while mRNA was determined by RT-PCR. The levels of inflammatory cytokines including TNF-α, IL-17, IL-1β in U251 glioma cells were evaluated by siRNA PHLPP1 and PHLPP1 addition. The loss of PHLPP1 expression occurs at high frequency in human gliomas. The highest mean values of PHLPP1 mRNA and protein were found in non-glioma brain tissues whereas the lowest mean values were found in those in glioblastoma with an increase of TNF-α, IL-17, IL-1β (p<0.05). PHLPP1 expression in human glioma was associated negatively with the severity of the tumor and inflammatory cytokines. siRNA PHLPP1 could increase the levels of inflammatory cytokines in U251 glioma cells while PHLPP1 addition could inhibit significantly inflammatory cytokines. We concluded that PHLPP1 played a suppression role in inflammatory response of glioma. The present study indicated that PHLPP1 could be used as a predictor for the prediction of the patients or as a therapeutic target for the treatment of human glioma.

[NUCLEAR STRUCTURE IN THE SECRETORY CELLS OF MAMMARY GLANDS IN LACTATING AND NON-LACTATING RATS]

The features of structural and functional organization of the main nuclear compartments and distribution of their key molecular components (chromatin-remodeling protein ATRX, RNA polymerase I and II, and the splicing factor SC35) has been studied in the nuclei of mammary gland cells at different functional states. No significant differences between the nuclei of the cells in the lactating and non-lactating mammary glands have been revealed at the ultrastructural level. At the same time, photometric analysis has revealed higher intensity of nucleoplasmic immunofluorescent staining of mammary glands in the lactating animals when antibodies against the proteins ATRX and SC35 were used. Apparently, this observation reflects the changes of the structural and functional status of chromatin as well as the redistribution of splicing factors between the sites of their deposition and transcription.

Chaperone BAG6 is dispensable for MHC class I antigen processing and presentation

Antigen processing for direct presentation on MHC class I molecules is a multistep process requiring the concerted activity of several cellular complexes. The essential steps at the beginning of this pathway, namely protein synthesis at the ribosome and degradation via the proteasome, have been known for years. Nevertheless, there is a considerable lack of factors identified to function between protein synthesis and degradation during antigen processing. Here, we analyzed the impact of the chaperone BAG6 on MHC class I cell surface expression and presentation of virus-derived peptides. Although an essential role of BAG6 in antigen processing has been proposed previously, we found BAG6 to be dispensable in this pathway. Still, interaction of BAG6 and the model antigen tyrosinase was enhanced during proteasome inhibition pointing towards a role of BAG6 in antigen degradation. Redundant chaperone pathways potentially mask the contribution of BAG6 to antigen processing and presentation.

An adoptive T cell immunotherapy targeting cancer stem cells in a colon cancer model

PURPOSE

Colon cancer is one of the most common malignancies worldwide. Cancer stem-like cells (CSCs) are a distinct subgroup of cancer cells that play a vital role in the development of cancer and also a role in the development of resistance against therapeutic agents. In this study we investigated the role of CSCs in colon cancer and evaluated the tumor-associated antigen CEP55 for targeting immunotherapeutically CSCs.

METHODS

Side population (SP) cells from colon cancer cell line SW480, were isolated using DNA-binding dye Hoechst 33342. The cytotoxic activity of cytotoxic T lymphocytes (CTL) clone 41 for side population (SP) cells and main population (MP) cells was evaluated using 51Cr release assay. The SP cells, MP cells and presorted cells from the colon cancer cell line were evaluated in NOD/SCID mice.

RESULTS

The isolated SP cells showed resistance to the chemotherapeutic agents irinotecan and oxaliplatin, which suggests that targeting the CSCs can be a better strategy for the treatment of chemotherapy-resistant colon cancer. HLA class I and HLA-A24 in SP cells and MP cells were expressed at the same level. We used CTL clone 41 to corroborate the sensitivity of SP cells to cytotoxic T lymphocyte response. The cytotoxic responses of SP cells were to the same extent as they were in MP cells and pre-sorted cells. Adoptive transfer of CTL clone 41 in immunodeficient mice inhibited SW480-induced tumors, suggesting that this approach can be used for colon cancer immunotherapy.

CONCLUSION

Our novel findings suggest that colon cancer CSCs are sensitive to CTLs, and CEP55, a tumor-associated antigen, can be successfully used as active immunotherapy for targeting CSCs in colon cancer.

Analogue peptides for the immunotherapy of human acute myeloid leukemia

The use of peptide vaccines, enhanced by adjuvants, has shown some efficacy in clinical trials. However, responses are often short-lived and rarely induce notable memory responses. The reason is that self-antigens have already been presented to the immune system as the tumor develops, leading to tolerance or some degree of host tumor cell destruction. To try to break tolerance against self-antigens, one of the methods employed has been to modify peptides at the anchor residues to enhance their ability to bind major histocompatibility complex molecules, extending their exposure to the T-cell receptor. These modified or analogue peptides have been investigated as stimulators of the immune system in patients with different cancers with variable but sometimes notable success. In this review we describe the background and recent developments in the use of analogue peptides for the immunotherapy of acute myeloid leukemia describing knowledge useful for the application of analogue peptide treatments for other malignancies.

The emerging role of nuclear viral DNA sensors

Detecting pathogenic DNA by intracellular receptors termed "sensors" is critical toward galvanizing host immune responses and eliminating microbial infections. Emerging evidence has challenged the dogma that sensing of viral DNA occurs exclusively in sub-cellular compartments normally devoid of cellular DNA. The interferon-inducible protein IFI16 was shown to bind nuclear viral DNA and initiate immune signaling, culminating in antiviral cytokine secretion. Here, we review the newly characterized nucleus-originating immune signaling pathways, their links to other crucial host defenses, and unique mechanisms by which viruses suppress their functions. We frame these findings in the context of human pathologies associated with nuclear replicating DNA viruses.

Structure and binding properties of a cameloid nanobody raised against KDM5B

The histone demethylase KDM5B is considered to be a promising target for anticancer therapy. Single-chain antibodies from llama (nanobodies) have been raised to aid in crystallization and structure determination of this enzyme. The antigen-binding properties of 15 of these nanobodies have been characterized. The crystal structure of one of these (NB17) has been determined to a resolution of 1.85 Å. NB17 crystallizes in space group P4322 with six molecules in the asymmetric unit. The six molecules in the asymmetric unit pack as an entity with approximate D3 symmetry with interactions mediated by the CDR loops, which could act as a crystallization nucleus. NB17 does not bind to monomeric KDM5B residues 1-820, but is found to bind to aggregates formed after incubation at 310 K.

Maintenance of Macrophage Redox Status by ChREBP Limits Inflammation and Apoptosis and Protects against Advanced Atherosclerotic Lesion Formation

Enhanced glucose utilization can be visualized in atherosclerotic lesions and may reflect a high glycolytic rate in lesional macrophages, but its causative role in plaque progression remains unclear. We observe that the activity of the carbohydrate-responsive element binding protein ChREBP is rapidly downregulated upon TLR4 activation in macrophages. ChREBP inactivation refocuses cellular metabolism to a high redox state favoring enhanced inflammatory responses after TLR4 activation and increased cell death after TLR4 activation or oxidized LDL loading. Targeted deletion of ChREBP in bone marrow cells resulted in accelerated atherosclerosis progression in Ldlr(-/-) mice with increased monocytosis, lesional macrophage accumulation, and plaque necrosis. Thus, ChREBP-dependent macrophage metabolic reprogramming hinders plaque progression and establishes a causative role for leukocyte glucose metabolism in atherosclerosis.

Isolation of neoantigen-specific T cells from tumor and peripheral lymphocytes

Adoptively transferred tumor-infiltrating T lymphocytes (TILs) that mediate complete regression of metastatic melanoma have been shown to recognize mutated epitopes expressed by autologous tumors. Here, in an attempt to develop a strategy for facilitating the isolation, expansion, and study of mutated antigen-specific T cells, we performed whole-exome sequencing on matched tumor and normal DNA isolated from 8 patients with metastatic melanoma. Candidate mutated epitopes were identified using a peptide-MHC-binding algorithm, and these epitopes were synthesized and used to generate panels of MHC tetramers that were evaluated for binding to tumor digests and cultured TILs used for the treatment of patients. This strategy resulted in the identification of 9 mutated epitopes from 5 of the 8 patients tested. Cells reactive with 8 of the 9 epitopes could be isolated from autologous peripheral blood, where they were detected at frequencies that were estimated to range between 0.4% and 0.002%. To the best of our knowledge, this represents the first demonstration of the successful isolation of mutation-reactive T cells from patients' peripheral blood prior to immune therapy, potentially providing the basis for designing personalized immunotherapies to treat patients with advanced cancer.

'Medusa-head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 1: Anti-mGluR1, anti-Homer-3, anti-Sj/ITPR1 and anti-CARP VIII

Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa-head antibodies' due to their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects and provides a summary and outlook.

Daxx from Pacific white shrimp Litopenaeus vannamei is involved in activation of NF-κB pathway

Death domain-associated factor 6 (Daxx) is a Fas-binding protein that mediates the activation of Jun amino-terminal kinase (JNK) pathway and Fas-induced apoptosis. In this study, a crustacean Daxx (LvDaxx) was firstly cloned and identified from Pacific white shrimp Litopenaeus vannamei. The LvDaxx cDNA was 2644 bp in length with an Open Reading Frame (ORF) of 2217 bp. Sequence analysis indicated that LvDaxx contained a single Daxx domain and two nuclear localization signals (NLSs) and shared a similarity with Drosophila melanogaster Daxx. LvDaxx was a nuclear-localized protein that was expressed highest in hemocytes and could be up-regulated in pathogen- and stimulant-challenge shrimps. LvDaxx could activate the artificial promoter containing an NF-κB binding site and the promoters of white spot syndrome virus (WSSV) ie1 gene and arthropod antimicrobial peptides (AMPs), suggesting LvDaxx could be involved in the activation of the NF-κB pathway. Knock-down of LvDaxx in vivo resulted in down-regulation of shrimp AMPs and reduction of WSSV copies in tissues. Furthermore, suppression of LvDaxx significantly decreased the mortality of WSSV-infected shrimps, but increased the mortality of Vibrio Parahaemolyticus-infected shrimps. Thus, these suggested that LvDaxx could play a role in the innate immunity against Vibrio parahaemolyticus in L. vannamei, while in the antiviral response, LvDaxx may be hijacked by WSSV and play a complex role in WSSV pathogenesis.

Proteasomal Degradation of Proinsulin Requires Derlin-2, HRD1 and p97

Patients with type 1 diabetes (T1D) suffer from beta-cell destruction by CD8⁺ T-cells that have preproinsulin as an important target autoantigen. It is of great importance to understand the molecular mechanism underlying the processing of preproinsulin into these CD8⁺ T-cell epitopes. We therefore studied a pathway that may contribute to the production of these antigenic peptides: degradation of proinsulin via ER associated protein degradation (ERAD). Analysis of the MHC class I peptide ligandome confirmed the presentation of the most relevant MHC class I-restricted diabetogenic epitopes in our cells: the signal peptide-derived sequence A15-A25 and the insulin B-chain epitopes H29-A38 and H34-V42. We demonstrate that specific silencing of Derlin-2, p97 and HRD1 by shRNAs increases steady state levels of proinsulin. This indicates that these ERAD constituents are critically involved in proinsulin degradation and may therefore also play a role in subsequent antigen generation. These ERAD proteins therefore represent interesting targets for novel therapies aiming at the reduction and possibly also prevention of beta-cell directed auto-immune reactions in T1D.

PRKDC mutations associated with immunodeficiency, granuloma, and autoimmune regulator-dependent autoimmunity

BACKGROUND

PRKDC encodes for DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a kinase that forms part of a complex (DNA-dependent protein kinase [DNA-PK]) crucial for DNA double-strand break repair and V(D)J recombination. In mice DNA-PK also interacts with the transcription factor autoimmune regulator (AIRE) to promote central T-cell tolerance.

OBJECTIVE

We sought to understand the causes of an inflammatory disease with granuloma and autoimmunity associated with decreasing T- and B-cell counts over time that had been diagnosed in 2 unrelated patients.

METHODS

Genetic, molecular, and functional analyses were performed to characterize an inflammatory disease evocative of a combined immunodeficiency.

RESULTS

We identified PRKDC mutations in both patients. These patients exhibited a defect in DNA double-strand break repair and V(D)J recombination. Whole-blood mRNA analysis revealed a strong interferon signature. On activation, memory T cells displayed a skewed cytokine response typical of TH2 and TH1 but not TH17. Moreover, mutated DNA-PKcs did not promote AIRE-dependent transcription of peripheral tissue antigens in vitro. The latter defect correlated in vivo with production of anti-calcium-sensing receptor autoantibodies, which are typically found in AIRE-deficient patients. In addition, 9 months after bone marrow transplantation, patient 1 had Hashimoto thyroiditis, suggesting that organ-specific autoimmunity might be linked to nonhematopoietic cells, such as AIRE-expressing thymic epithelial cells.

CONCLUSION

Deficiency of DNA-PKcs, a key AIRE partner, can present as an inflammatory disease with organ-specific autoimmunity, suggesting a role for DNA-PKcs in regulating autoimmune responses and maintaining AIRE-dependent tolerance in human subjects.

Altered HLA Class I Profile Associated with Type A/D Nucleophosmin Mutation Points to Possible Anti-Nucleophosmin Immune Response in Acute Myeloid Leukemia

Nucleophosmin 1 (NPM1) mutations are frequently found in patients with acute myeloid leukemia (AML) and the newly generated sequences were suggested to induce immune response contributing to the relatively favorable outcome of patients in this AML subset. We hypothesized that if an efficient immune response against mutated nucleophosmin can be induced in vivo, the individuals expressing HLA alleles suitable for presenting NPM-derived peptides should be less prone to developing AML associated with NPM1 mutation. We thus compared HLA class I frequencies in a cohort of patients with mutated NPM1 (63 patients, NPMc+), a cohort of patients with wild-type NPM1 (94 patients, NPMwt) and in normal individuals (large datasets available from Allele Frequency Net Database). Several HLA allelic groups were found to be depleted in NPMc+ patients, but not in NPMwt compared to the normal distribution. The decrease was statistically significant for HLA B*07, B*18, and B*40. Furthermore, statistically significant advantage in the overall survival was found for patients with mutated NPM1 expressing at least one of the depleted allelic groups. The majority of the depleted alleles were predicted to bind potent NPM-derived immunopeptides and, importantly, these peptides were often located in the unmutated part of the protein. Our analysis suggests that individuals expressing specific HLA allelic groups are disposed to develop an efficient anti-AML immune response thanks to aberrant cytoplasmic localization of the mutated NPM protein.

Diagnostic potential of zinc finger protein-specific autoantibodies and associated linear B-cell epitopes in colorectal cancer

Colorectal cancer is one of the most common cancers worldwide with almost 700,000 deaths every year. Detection of colorectal cancer at an early stage significantly improves patient survival. Cancer-specific autoantibodies found in sera of cancer patients can be used for pre-symptomatic detection of the disease. In this study we assess the zinc finger proteins ZNF346, ZNF638, ZNF700 and ZNF768 as capture antigens for the detection of autoantibodies in colorectal cancer. Sera from 96 patients with colorectal cancer and 35 control patients with no evidence of cancer on colonoscopy were analysed for the presence of ZNF-specific autoantibodies using an indirect ELISA. Autoantibodies to individual ZNF proteins were detected in 10–20% of colorectal cancer patients and in 0–5.7% of controls. A panel of all four ZNF proteins resulted in an assay specificity of 91.4% and sensitivity of 41.7% for the detection of cancer patients in a cohort of non-cancer controls and colorectal cancer patients. Clinicopathological and survival analysis revealed that ZNF autoantibodies were independent of disease stage and did not correlate with disease outcome. Since ZNF autoantibodies were shared between patients and corresponding ZNF proteins showed similarities in their zinc finger motifs, we performed an in silico epitope sequence analysis. Zinc finger proteins ZNF700 and ZNF768 showed the highest sequence similarity with a bl2seq score of 262 (E-value 1E-81) and their classical C2H2 ZNF motifs were identified as potential epitopes contributing to their elevated immunogenic potential. Our findings show an enhanced and specific immunogenicity to zinc finger proteins, thereby providing a multiplexed autoantibody assay for minimally invasive detection of colorectal cancer.

Initial in vivo experience of pig artery patch transplantation in baboons using mutant MHC (CIITA-DN) pigs

BACKGROUND

In the pig-to-nonimmunosuppressed baboon artery patch model, a graft from an α1,3-galactosyltransferase gene-knockout pig transgenic for human CD46 (GTKO/CD46) induces a significant adaptive immune response (elicited anti-pig antibody response, increase in T cell proliferation on MLR, cellular infiltration of the graft), which is effectively prevented by anti-CD154mAb-based therapy.

METHODS

As anti-CD154mAb is currently not clinically applicable, we evaluated whether it could be replaced by CD28/B7 pathway blockade or by blockade of both pathways (using belatacept + anti-CD40mAb [2C10R4]). We further investigated whether a patch from a GTKO/CD46 pig with a mutant human MHC class II transactivator (CIITA-DN) gene would allow reduction in the immunosuppressive therapy administered.

RESULTS

When grafts from GTKO/CD46 pigs were transplanted with blockade of both pathways, a minimal or insignificant adaptive response was documented. When a GTKO/CD46/CIITA-DN graft was transplanted, but no immunosuppressive therapy was administered, a marked adaptive response was documented. In the presence of CD28/B7 pathway blockade (abatacept or belatacept), there was a weak adaptive response that was diminished when compared with that to a GTKO/CD46 graft. Blockade of both pathways prevented an adaptive response.

CONCLUSION

Although expression of the mutant MHC CIITA-DN gene was associated with a reduced adaptive immune response when immunosuppressive therapy was inadequate, when blockade of both the CD40/CD154 and CD28/B7 pathways was present, the response even to a GTKO/CD46 graft was suppressed. This was confirmed after GTKO/CD46 heart transplantation in baboons.

Arabidopsis HFR1 is a potential nuclear substrate regulated by the Xanthomonas type III effector XopD(Xcc8004)

XopDXcc8004, a type III effector of Xanthomonas campestris pv. campestris (Xcc) 8004, is considered a shorter version of the XopD, which lacks the N-terminal domain. To understand the functions of XopDXcc8004, in planta, a transgenic approach combined with inducible promoter to analyze the effects of XopDXcc8004 in Arabidopsis was done. Here, the expression of XopDXcc8004, in Arabidopsis elicited the accumulation of host defense-response genes. These molecular changes were dependent on salicylic acid and correlated with lesion-mimic phenotypes observed in XVE::XopDXcc8004 transgenic plants. Moreover, XopDXcc8004 was able to desumoylate HFR1, a basic helix-loop-helix transcription factor involved in photomorphogenesis, through SUMO protease activity. Interestingly, the hfr1-201 mutant increased the expression of host defense-response genes and displayed a resistance phenotype to Xcc8004. These data suggest that HFR1 is involved in plant innate immunity and is potentially regulated by XopDXcc8004.

Adiponectin induces A20 expression in adipose tissue to confer metabolic benefit

Obesity is a major risk factor for metabolic disease, with white adipose tissue (WAT) inflammation emerging as a key underlying pathology. We detail that mice lacking Reverbα exhibit enhanced fat storage without the predicted increased WAT inflammation or loss of insulin sensitivity. In contrast to most animal models of obesity and obese human patients, Reverbα(-/-) mice exhibit elevated serum adiponectin levels and increased adiponectin secretion from WAT explants in vitro, highlighting a potential anti-inflammatory role of this adipokine in hypertrophic WAT. Indeed, adiponectin was found to suppress primary macrophage responses to lipopolysaccharide and proinflammatory fatty acids, and this suppression depended on glycogen synthase kinase 3β activation and induction of A20. Attenuated inflammatory responses in Reverbα(-/-) WAT depots were associated with tonic elevation of A20 protein and ex vivo shown to depend on A20. We also demonstrate that adipose A20 expression in obese human subjects exhibits a negative correlation with measures of insulin sensitivity. Furthermore, bariatric surgery-induced weight loss was accompanied by enhanced WAT A20 expression, which is positively correlated with increased serum adiponectin and improved metabolic and inflammatory markers, including C-reactive protein. The findings identify A20 as a mediator of adiponectin anti-inflammatory action in WAT and a potential target for mitigating obesity-related pathology.

Characterization of two regulators of the TNF-α signaling pathway in Apostichopus japonicus: LPS-induced TNF-α factor and baculoviral inhibitor of apoptosis repeat-containing 2

The TNF-α signaling cascade is involved in the regulation of a variety of biological processes, including cell proliferation, differentiation, apoptosis and the immune response in vertebrates. Here, two regulatory genes, lipopolysaccharide-induced tumor necrosis factor α factor (LITAF) and baculoviral inhibitor of apoptosis repeat-containing 2 (BIRC2), were identified in coelomocytes from the sea cucumber Apostichopus japonicus by RNA-seq and RACE (denoted as AjLITAF and AjBIRC2, respectively). The full-length cDNA of AjLITAF was 1417 bp, with a 5' untranslated region (UTR) of 189 bp, a 3' UTR of 637 bp with one cytokine RNA instability motif (ATTTA) and an open reading frame (ORF) of 591 bp encoding a polypeptide of 196 amino acid residues and a predicted molecular weight of 22.1 kDa. The partial AjBIRC2 cDNA was 2324 bp with a 5' UTR of 145 bp, a 3' UTR of 469 bp and a complete ORF of 1710 bp encoding a polypeptide of 569 amino acid residues. Analysis of the deduced amino acid sequences revealed that both genes shared a remarkably high degree of structural conservation with their mammalian orthologs, including a highly conserved LITAF domain in AjLITAF and three types of BIR domains in AjBIRC2. Spatial expression analysis revealed that AjLITAF and AjBIRC2 were expressed at a slightly lower level in the intestine and tentacle tissues compared with the other four tissues examined. After challenging the sea cucumbers with Vibrio splendidus, the expression levels of AjLITAF and AjBIRC2 in coelomocytes were increased by 2.65-fold at 6 h and 1.76-fold at 24 h compared with the control group. In primary cultured coelomocytes, a significant increase in the expression of AjLITAF and AjBIRC2 was detected after 6 h of exposure to 1 µg mL(-1) LPS. Together, these results suggest that AjLITAF and AjBIRC2 might be involved in the sea cucumber immune response during the course of a pathogenic infection or exposure to pathogen-associated molecular pattern (PAMP) molecules.

The interferon-inducible DNA-sensor protein IFI16: a key player in the antiviral response

IFI16, a member of the IFN-inducible PYHIN-200 gene family, displays multifaceted activity due to its ability to bind to various target proteins and, in turn, modulate a variety cell functions including proliferation, differentiation, apoptosis/pyroptosis, senescence, and in? ammation. The last few year have seen major advances in our knowledge of IFI16 antiviral activity and its role in the immune response. Indeed, a wealth of evidence now supports a key role of IFI16 in the activation of innate immunity and viral restriction against Herpesviruses and Lentiviruses, such that the definition of IFI16 as a "restriction factor" is now widely accepted. However, most viruses have developed their own unique strategy to antagonize IFI16, leading to a modification or disruption of its function. This review summarizes our current understanding of how viral replication is sensed and then inhibited by IFI16 protein and the viral strategies employed to defeat this host defense mechanism. We will focus mainly on Herpesviruses, although recent discoveries on the role of IFI16 in lentiviral infection will also be considered.