Search

The expression of BTB-ZF transcription factors such as ThPOK in CD4 + T cells, Bcl6 in T follicular helper cells, and PLZF in natural killer T cells defines the fundamental nature and characteristics of these cells. Screening for lineage-defining BTB-ZF genes led to the discovery of a subset of T cells that expressed Zbtb20. About half of Zbtb20 + T cells expressed FoxP3, the lineage-defining transcription factor for regulatory T cells (T regs ). Zbtb20 + T regs were phenotypically and genetically distinct from the larger conventional T reg population. Zbtb20 + T regs constitutively expressed mRNA for interleukin-10 and produced high levels of the cytokine upon primary activation. Zbtb20 + T regs were enriched in the intestine and specifically expanded when inflammation was induced by the use of dextran sodium sulfate. Conditional deletion of Zbtb20 in T cells resulted in a loss of intestinal epithelial barrier integrity. Consequently, knockout (KO) mice were acutely sensitive to colitis and often died because of the disease. Adoptive transfer of Zbtb20 + T regs protected the Zbtb20 conditional KO mice from severe colitis and death, whereas non-Zbtb20 T regs did not. Zbtb20 was detected in CD24 hi double-positive and CD62L lo CD4 single-positive thymocytes, suggesting that expression of the transcription factor and the phenotype of these cells were induced during thymic development. However, Zbtb20 expression was not induced in "conventional" T regs by activation in vitro or in vivo. Thus, Zbtb20 expression identified and controlled the function of a distinct subset of T regs that are involved in intestinal homeostasis.

Devil facial tumour disease (DFTD) comprises two genetically distinct transmissible cancers (DFT1 and DFT2) endangering the survival of the Tasmanian devil (Sarcophilus harrisii) in the wild. DFT1 first arose from a cell of the Schwann cell lineage; however, the tissue-of-origin of the recently discovered DFT2 cancer is unknown. In this study, we compared the transcriptome and proteome of DFT2 tumours to DFT1 and normal Tasmanian devil tissues to determine the tissue-of-origin of the DFT2 cancer. Our findings demonstrate that DFT2 expresses a range of Schwann cell markers and exhibits expression patterns consistent with a similar origin to the DFT1 cancer. Furthermore, DFT2 cells express genes associated with the repair response to peripheral nerve damage. These findings suggest that devils may be predisposed to transmissible cancers of Schwann cell origin. The combined effect of factors such as frequent nerve damage from biting, Schwann cell plasticity and low genetic diversity may allow these cancers to develop on rare occasions. The emergence of two independent transmissible cancers from the same tissue in the Tasmanian devil presents an unprecedented opportunity to gain insight into cancer development, evolution and immune evasion in mammalian species.

Spinal dorsal interneurons, which are generated during embryonic development, relay and process sensory inputs from the periphery to the central nervous system. Proper integration of these cells into neuronal circuitry depends on their correct positioning within the spinal parenchyma. Molecular cues that control neuronal migration have been extensively characterized but the genetic programs that regulate their production remain poorly investigated. Onecut (OC) transcription factors have been shown to control the migration of the dorsal interneurons (dINs) during spinal cord development. Here, we report that the OC factors moderate the expression of Pou2f2 , a transcription factor essential for B-cell differentiation, in spinal dINs. Overexpression or inactivation of Pou2f2 leads to alterations in the differentiation of dI2, dI3 and Phox2a-positive dI5 populations and to defects in the distribution of dI2-dI6 interneurons. Thus, an OC-Pou2f2 genetic cascade regulates adequate diversification and distribution of dINs during embryonic development., (Copyright © 2019 Masgutova, Harris, Jacob, Corcoran and Clotman.)

Class-switch recombination (CSR) is a DNA recombination process that replaces the immunoglobulin (Ig) constant region for the isotype that can best protect against the pathogen. Dysregulation of CSR can cause self-reactive BCRs and B cell lymphomas; understanding the timing and location of CSR is therefore important. Although CSR commences upon T cell priming, it is generally considered a hallmark of germinal centers (GCs). Here, we have used multiple approaches to show that CSR is triggered prior to differentiation into GC B cells or plasmablasts and is greatly diminished in GCs. Despite finding a small percentage of GC B cells expressing germline transcripts, phylogenetic trees of GC BCRs from secondary lymphoid organs revealed that the vast majority of CSR events occurred prior to the onset of somatic hypermutation. As such, we have demonstrated the existence of IgM-dominated GCs, which are unlikely to occur under the assumption of ongoing switching., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Acquisition of proper neuronal identity and position is critical for the formation of neural circuits. In the embryonic spinal cord, cardinal populations of interneurons diversify into specialized subsets and migrate to defined locations within the spinal parenchyma. However, the factors that control interneuron diversification and migration remain poorly characterized. Here, we show that the Onecut transcription factors are necessary for proper diversification and distribution of the V2 interneurons in the developing spinal cord. Furthermore, we uncover that these proteins restrict and moderate the expression of spinal isoforms of Pou2f2 , a transcription factor known to regulate B-cell differentiation. By gain- or loss-of-function experiments, we show that Pou2f2 contribute to regulate the position of V2 populations in the developing spinal cord. Thus, we uncovered a genetic pathway that regulates the diversification and the distribution of V2 interneurons during embryonic development.

Dendritic cells (DCs) are can be broadly divided into conventional (cDC) and plasmacytoid (pDC) subsets. Despite the importance of this lineage diversity, its genetic basis is not fully understood. We found that conditional ablation of the Ets-family transcription factor PU.1 in DC-restricted progenitors led to increased pDC production at the expense of cDCs. PU.1 controlled many of the cardinal functions of DCs, such as antigen presentation by cDCs and type I interferon production by pDCs. Conditional ablation of PU.1 de-repressed the pDC transcriptional signature in cDCs. The combination of genome-wide mapping of PU.1 binding and gene expression analysis revealed a key role for PU.1 in maintaining cDC identity through the induction of the transcriptional regulator DC-SCRIPT. PU.1 activated DC-SCRIPT expression, which in turn promoted cDC formation, particularly of cDC1s, and repressed pDC development. Thus, cDC identity is regulated by a transcriptional node requiring PU.1 and DC-SCRIPT., (Copyright © 2018 Elsevier Inc. All rights reserved.)

During haematopoiesis, haematopoietic stem cells differentiate into restricted potential progenitors before maturing into the many lineages required for oxygen transport, wound healing and immune response. We have updated Haemopedia, a database of gene-expression profiles from a broad spectrum of haematopoietic cells, to include RNA-seq gene-expression data from both mice and humans. The Haemopedia RNA-seq data set covers a wide range of lineages and progenitors, with 57 mouse blood cell types (flow sorted populations from healthy mice) and 12 human blood cell types. This data set has been made accessible for exploration and analysis, to researchers and clinicians with limited bioinformatics experience, on our online portal Haemosphere: https://www.haemosphere.org. Haemosphere also includes nine other publicly available high-quality data sets relevant to haematopoiesis. We have added the ability to compare gene expression across data sets and species by curating data sets with shared lineage designations or to view expression gene vs gene, with all plots available for download by the user.

Gain-of-function (GOF) mutations in PIK3CD , encoding the p110δ subunit of phosphatidylinositide 3-kinase (PI3K), cause a primary immunodeficiency. Affected individuals display impaired humoral immune responses following infection or immunization. To establish mechanisms underlying these immune defects, we studied a large cohort of patients with PIK3CD GOF mutations and established a novel mouse model using CRISPR/Cas9-mediated gene editing to introduce a common pathogenic mutation in Pik3cd In both species, hyperactive PI3K severely affected B cell development and differentiation in the bone marrow and the periphery. Furthermore, PI3K GOF B cells exhibited intrinsic defects in class-switch recombination (CSR) due to impaired induction of activation-induced cytidine deaminase (AID) and failure to acquire a plasmablast gene signature and phenotype. Importantly, defects in CSR, AID expression, and Ig secretion were restored by leniolisib, a specific p110δ inhibitor. Our findings reveal key roles for balanced PI3K signaling in B cell development and long-lived humoral immunity and memory and establish the validity of treating affected individuals with p110δ inhibitors., (© 2018 Avery et al.)

Antibody Secreting Cells (ASCs) are a fundamental component of humoral immunity, however, deregulated or excessive antibody production contributes to the pathology of autoimmune diseases, while transformation of ASCs results in the malignancy Multiple Myeloma (MM). Despite substantial recent improvements in treating these conditions, there is as yet no widely used ASC-specific therapeutic approach, highlighting a critical need to identify novel methods of targeting normal and malignant ASCs. Surface molecules specifically expressed by the target cell population represent ideal candidates for a monoclonal antibody-based therapy. By interrogating the ASC gene signature that we previously defined we identified three surface proteins, Plpp5, Clptm1l and Itm2c, which represent potential targets for novel MM treatments. Plpp5 , Clptm1l and Itm2c are highly and selectively expressed by mouse and human ASCs as well as MM cells. To investigate the function of these proteins within the humoral immune system we have generated three novel mouse strains, each carrying a loss-of-function mutation in either Plpp5 , Clptm1l or Itm2c . Through analysis of these novel strains, we have shown that Plpp5, Clptm1l and Itm2c are dispensable for the development, maturation and differentiation of B-lymphocytes, and for the production of antibodies by ASCs. As adult mice lacking either protein showed no apparent disease phenotypes, it is likely that targeting these molecules on ASCs will have minimal on-target adverse effects.

As a topical cancer immunotherapy, the toll-like receptor 7 ligand imiquimod activates tumor regression via stimulation of immune cell infiltration and cytotoxic responses. Imiquimod also exerts direct pro-apoptotic effects on tumor cells in vitro , but a role for these effects in imiquimod-induced tumor regression remains undefined. We previously demonstrated that cell lines derived from devil facial tumor disease (DFTD), a transmissible cancer threatening the survival of the Tasmanian devil ( Sarcophilus harrisii ), are sensitive to imiquimod-induced apoptosis. In this study, the pro-apoptotic effects of imiquimod in DFTD have been investigated using RNA-sequencing and label-free quantitative proteomics. This analysis revealed that changes to gene and protein expression in imiquimod treated DFTD cells are consistent with the onset of oxidative and endoplasmic reticulum stress responses, and subsequent activation of the unfolded protein response, autophagy, cell cycle arrest and apoptosis. Imiquimod also regulates the expression of oncogenic pathways, providing a direct mechanism by which this drug may increase tumor susceptibility to immune cytotoxicity in vivo . Our study has provided the first global analysis of imiquimod-induced effects in any tumor cell line. These findings have highlighted the potential of cell stress pathways as therapeutic targets in DFTD, and will allow for improved mechanistic use of imiquimod as a therapy in both the Tasmanian devil and human cancers., Competing Interests: CONFLICTS OF INTEREST The authors declare no potential conflicts of interest.

Devil facial tumor disease (DFTD) is renowned for its successful evasion of the host immune system. Down regulation of the major histocompatabilty complex class I molecule (MHC-I) on the DFTD cells is a primary mechanism of immune escape. Immunization trials on captive Tasmanian devils have previously demonstrated that an immune response against DFTD can be induced, and that immune-mediated tumor regression can occur. However, these trials were limited by their small sample sizes. Here, we describe the results of two DFTD immunization trials on cohorts of devils prior to their wild release as part of the Tasmanian Government's Wild Devil Recovery project. 95% of the devils developed anti-DFTD antibody responses. Given the relatively large sample sizes of the trials ( N  = 19 and N  = 33), these responses are likely to reflect those of the general devil population. DFTD cells manipulated to express MHC-I were used as the antigenic basis of the immunizations in both trials. Although the adjuvant composition and number of immunizations differed between trials, similar anti-DFTD antibody levels were obtained. The first trial comprised DFTD cells and the adjuvant combination of ISCOMATRIX™, polyIC, and CpG with up to four immunizations given at monthly intervals. This compared to the second trial whereby two immunizations comprising DFTD cells and the adjuvant combination ISCOMATRIX™, polyICLC (Hiltonol ® ) and imiquimod were given a month apart, providing a shorter and, therefore, more practical protocol. Both trials incorporated a booster immunization given up to 5 months after the primary course. A key finding was that devils in the second trial responded more quickly and maintained their antibody levels for longer compared to devils in the first trial. The different adjuvant combination incorporating the RNAase resistant polyICLC and imiquimod used in the second trial is likely to be responsible. The seroconversion in the majority of devils in these anti-DFTD immunization trials was remarkable, especially as DFTD is hallmarked by its immune evasion mechanisms. Microsatellite analyzes of MHC revealed that some MHC-I microsatellites correlated to stronger immune responses. These trials signify the first step in the long-term objective of releasing devils with immunity to DFTD into the wild.

Devil facial tumour disease (DFTD) describes two genetically distinct transmissible tumours that pose a significant threat to the survival of the Tasmanian devil. A prophylactic vaccine could protect devils from DFTD transmission. For this vaccine to be effective, potent immune adjuvants will be required. Toll-like receptors (TLRs) promote robust immune responses in human cancer studies and are highly conserved across mammalian species. In this study, we investigated the proficiency of TLR ligands for immune activation in the Tasmanian devil using in vitro mononuclear cell stimulations and in vivo immunisation trials with a model antigen. We identified two such TLR ligands, polyICLC (Hiltonol ® ) (TLR3) and imiquimod (TLR7), that in combination induced significant IFNγ production from Tasmanian devil lymphocytes in vitro. Immunisation with these ligands and the model antigen keyhole limpet haemocyanin activated robust antigen-specific primary, secondary and long-term memory IgG responses. Our results support the conserved nature of TLR signaling across mammalian species. PolyICLC and imiquimod will be trialed as immune adjuvants in future DFTD vaccine formulations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Bcl6 (B-cell lymphoma 6) is a transcriptional repressor and critical mediator of the germinal center reaction during a T-cell-dependent antibody response, where it enables somatic hypermutation of immunoglobulin genes and inhibits terminal differentiation via repression of Blimp1. It can also contribute to the development of diffuse large B-cell lymphoma when expressed inappropriately. Bcl6 regulation is mediated both at the transcriptional and post-transcriptional levels, and in particular a strong signal through the B-cell receptor causes rapid proteasomal degradation of Bcl6. Despite the importance of Bcl6 in both immunity and cancer, little is known about how other extrinsic factors regulate Bcl6 in B cells. Here we show that Bcl6 is indeed highly unstable in B cells after a B-cell receptor (BCR) signal, but that the T-cell-derived cytokines interleukin 4 (IL4) and IL21 counteract BCR-mediated degradation, preserving Bcl6 protein levels. Stat6, downstream of IL4, can induce Bcl6 transcription directly. In vivo, B-cell intrinsic loss of IL4 or IL21 signaling reduces the magnitude or duration of the GC response, respectively, while their combined loss almost completely eliminates the GC response. This work provides key insights into the effect mediated by T-follicular helper cytokines on Bcl6 regulation.

Devil facial tumour disease (DFTD) is a transmissible cancer devastating the Tasmanian devil (Sarcophilus harrisii) population. The cancer cell is the 'infectious' agent transmitted as an allograft by biting. Animals usually die within a few months with no evidence of antibody or immune cell responses against the DFTD allograft. This lack of anti-tumour immunity is attributed to an absence of cell surface major histocompatibility complex (MHC)-I molecule expression. While the endangerment of the devil population precludes experimentation on large experimental groups, those examined in our study indicated that immunisation and immunotherapy with DFTD cells expressing surface MHC-I corresponded with effective anti-tumour responses. Tumour engraftment did not occur in one of the five immunised Tasmanian devils, and regression followed therapy of experimentally induced DFTD tumours in three Tasmanian devils. Regression correlated with immune cell infiltration and antibody responses against DFTD cells. These data support the concept that immunisation of devils with DFTD cancer cells can successfully induce humoral responses against DFTD and trigger immune-mediated regression of established tumours. Our findings support the feasibility of a protective DFTD vaccine and ultimately the preservation of the species.

T lymphocytes and B lymphocytes integrate activating signals to control the size of their proliferative response. Here we report that such control was achieved by timed changes in the production rate of cell-cycle-regulating proto-oncoprotein Myc, with division cessation occurring when Myc levels fell below a critical threshold. The changing pattern of the level of Myc was not affected by cell division, which identified the regulating mechanism as a cell-intrinsic, heritable temporal controller. Overexpression of Myc in stimulated T cells and B cells did not sustain cell proliferation indefinitely, as a separate 'time-to-die' mechanism, also heritable, was programmed after lymphocyte activation and led to eventual cell loss. Together the two competing cell-intrinsic timed fates created the canonical T cell and B cell immune-response pattern of rapid growth followed by loss of most cells. Furthermore, small changes in these timed processes by regulatory signals, or by oncogenic transformation, acted in synergy to greatly enhance cell numbers over time.

The devil facial tumor disease (DFTD) is caused by clonal transmissible cancers that have led to a catastrophic decline in the wild Tasmanian devil ( Sarcophilus harrisii ) population. The first transmissible tumor, now termed devil facial tumor 1 (DFT1), was first discovered in 1996 and has been continually transmitted to new hosts for at least 20 years. In 2015, a second transmissible cancer [devil facial tumor 2 (DFT2)] was discovered in wild devils, and the DFT2 is genetically distinct and independent from the DFT1. Despite the estimated 136,559 base pair substitutions and 14,647 insertions/deletions in the DFT1 genome as compared to two normal devil reference genomes, the allograft tumors are not rejected by the host immune system. Additionally, genome sequencing of two sub-strains of DFT1 detected greater than 15,000 single-base substitutions that were found in only one of the DFT1 sub-strains, demonstrating the transmissible tumors are evolving and that generation of neoantigens is likely ongoing. Recent evidence in human clinical trials suggests that blocking PD-1:PD-L1 interactions promotes antitumor immune responses and is most effective in cancers with a high number of mutations. We hypothesized that DFTD cells could exploit the PD-1:PD-L1 inhibitory pathway to evade antitumor immune responses. We developed recombinant proteins and monoclonal antibodies (mAbs) to provide the first demonstration that PD-1 binds to both PD-L1 and PD-L2 in a non-placental mammal and show that PD-L1 is upregulated in DFTD cells in response to IFN-γ. Immunohistochemistry showed that PD-L1 is rarely expressed in primary tumor masses, but low numbers of PD-L1 + non-tumor cells were detected in the microenvironment of several metastatic tumors. Importantly, in vitro testing suggests that PD-1 binding to PD-L1 and PD-L2 can be blocked by mAbs, which could be critical to understanding how the DFT allografts evade the immune system.

Devil facial tumour disease (DFTD) is a transmissible cancer that has brought the host species, the Tasmanian devil, to the brink of extinction. The cancer cells avoid allogeneic immune recognition by downregulating cell surface major histocompatibility complex (MHC) I expression. This should prevent CD8(+) T cell, but not natural killer (NK) cell, cytotoxicity. The reason why NK cells, normally reactive to MHC-negative cells, are not activated to kill DFTD cells has not been determined. The immune response of wild devils to DFTD, if it occurs, is uncharacterised. To investigate this, we tested 12 wild devils with DFTD, and found suggestive evidence of low levels of antibodies against DFTD cells in one devil. Eight of these devils were also analysed for cytotoxicity, however, none showed evidence for cytotoxicity against cultured DFTD cells. To establish whether mimicking activation of antitumour responses could induce cytotoxic activity against DFTD, Tasmanian devil peripheral blood mononuclear cells (PBMCs) were treated with either the mitogen Concanavalin A, the Toll-like receptor agonist polyinosinic:polycytidylic acid or recombinant Tasmanian devil IL-2. All induced the PBMC cells to kill cultured DFTD cells, suggesting that activation does not occur after encounter with DFTD cells in vivo, but can be induced. The identification of agents that activate cytotoxicity against DFTD target cells is critical for developing strategies to protect against DFTD. Such agents could function as adjuvants to induce functional immune responses capable of targeting DFTD cells and tumours in vivo.

Long-lived plasma cells (LLPCs) are durable antibody-producing cells that are key to immunity. Bhattacharya and colleagues find that LLPCs derive their enhanced survival capacity from a higher rate of glucose import. Some of this glucose sustains the cells through glycolysis, while the bulk is required for antibody glycosylation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

E proteins and their antagonists, the Id proteins, are transcriptional regulators important for normal hematopoiesis. We found that Id2 acts as a key regulator of leukemia stem cell (LSC) potential in MLL-rearranged acute myeloid leukemia (AML). Low endogenous Id2 expression is associated with LSC enrichment while Id2 overexpression impairs MLL-AF9-leukemia initiation and growth. Importantly, MLL-AF9 itself controls the E-protein pathway by suppressing Id2 while directly activating E2-2 expression, and E2-2 depletion phenocopies Id2 overexpression in MLL-AF9-AML cells. Remarkably, Id2 tumor-suppressive function is conserved in t(8;21) AML. Low expression of Id2 and its associated gene signature are associated with poor prognosis in MLL-rearranged and t(8;21) AML patients, identifying the Id2/E-protein axis as a promising new therapeutic target in AML., (Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.)

The koala (Phascolarctos cinereus) is an arboreal herbivorous marsupial that is an Australian icon. Koalas in many parts of Australia are under multiple threats including habitat destruction, dog attacks, vehicular accidents, and infectious diseases such as Chlamydia spp. and the koala retrovirus (KoRV), which may contribute to the incidence of lymphoma and leukaemia in this species. Due to a lack of koala-specific immune reagents and assays there is currently no way to adequately analyse the immune response in healthy, diseased or vaccinated animals. This paper reports the production and characterisation of the first anti-koala CD4 monoclonal antibody (mAb). The koala CD4 gene was identified and used to develop recombinant proteins for mAb production. Fluorochrome-conjugated anti-CD4 mAb was used to measure the levels of CD4(+) lymphocytes collected from koala spleens (41.1%, range 20-45.1%) lymph nodes (36.3%, range 19-55.9%) and peripheral blood (23.8%, range 17.3-35%) by flow cytometry. Biotin-conjugated anti-CD4 mAb was used for western blot to determine an approximate size of 52 kDa for the koala CD4 molecule and used in immunohistochemistry to identify CD4(+) cells in the paracortical region and germinal centres of spleen and lymph nodes. Using the anti-CD4 mab we showed that CD4 cells from vaccinated, but not control, koalas proliferated following in vitro stimulation with UV-inactivated Chlamydia pecorum and recombinant chlamydial antigens. Since CD4(+) T cells have been shown to play a pivotal role in clearing chlamydial infection in both human and mouse infections, using this novel antibody will help determine the role CD4(+) T cells play in protection against chlamydial infection in koalas and also enhance our knowledge of how KoRV affects the koala immune system., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The Ets family transcription factor PU.1 and the interferon regulatory factor (IRF)4 and IRF8 regulate gene expression by binding to composite DNA sequences known as Ets/interferon consensus elements. Although all three factors are expressed from the onset of B-cell development, single deficiency of these factors in B-cell progenitors only mildly impacts on bone marrow B lymphopoiesis. Here we tested whether PU.1 cooperates with IRF factors in regulating early B-cell development. Lack of PU.1 and IRF4 resulted in a partial block in development the pre-B-cell stage. The combined deletion of PU.1 and IRF8 reduced recirculating B-cell numbers. Strikingly, all PU.1/IRF4 and ~50% of PU.1/IRF8 double deficient mice developed pre-B-cell acute lymphoblastic leukemia (B-ALL) associated with reduced expression of the established B-lineage tumor suppressor genes, Ikaros and Spi-B. These genes are directly regulated by PU.1/IRF4/IRF8, and restoration of Ikaros or Spi-B expression inhibited leukemic cell growth. In summary, we demonstrate that PU.1, IRF4 and IRF8 cooperate to regulate early B-cell development and to prevent pre-B-ALL formation., Competing Interests: The authors declare no competing financial interests.

The generation of high-affinity antibodies requires germinal center (GC) development and differentiation of long-lived plasma cells in a multilayered process that is tightly controlled by the activity of multiple transcription factors. Here, we reveal a new layer of complexity by demonstrating that dynamic changes in Id3 and E-protein activity govern both GC and plasma cell differentiation. We show that down-regulation of Id3 in B cells is essential for releasing E2A and E2-2, which in a redundant manner are required for antigen-induced B cell differentiation. We demonstrate that this pathway controls the expression of multiple key factors, including Blimp1, Xbp1, and CXCR4, and is therefore critical for establishing the transcriptional network that controls GC B cell and plasma cell differentiation., (© 2016 Gloury et al.)

Plasmacytoid dendritic cells (pDCs) represent a unique immune cell type that responds to viral nucleic acids through the rapid production of type I interferons. Within the hematopoietic system, the transcription factor RUNX2 is exclusively expressed in pDCs and is required for their peripheral homeostasis. Here, we show that RUNX2 plays an essential role in promoting pDC localization and function. RUNX2 is required for the appropriate expression of the integrin-mediated adhesion machinery, as well as for the down-modulation of the chemokine receptor CXCR4, which allows pDC egress into the circulation. RUNX2 also facilitates the robust response to viral infection through the control of IRF7, the major regulator of type I interferon production. Mice lacking one copy of Runx2 have reduced numbers of peripheral pDCs and IFN-α expression, which might contribute to the reported difficulties of individuals with cleidocranial dysplasia, who are haploinsufficient for RUNX2, to clear viral infections., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

We examined the role of NFκB1 in the homeostasis and function of peripheral follicular (Fo) B cells. Aging mice lacking NFκB1 (Nfκb1(-/-)) develop lymphoproliferative and multiorgan autoimmune disease attributed in large part to the deregulated activity of Nfκb1(-/-)Fo B cells that produce excessive levels of the proinflammatory cytokine interleukin 6 (IL-6). Despite enhanced germinal center (GC) B cell differentiation, the formation of GC structures was severely disrupted in the Nfκb1(-/-)mice. Bone marrow chimeric mice revealed that the Fo B cell-intrinsic loss of NFκB1 led to the spontaneous generation of GC B cells. This was primarily the result of an increase in IL-6 levels, which promotes the differentiation of Fo helper CD4(+)T cells and acts in an autocrine manner to reduce antigen receptor and toll-like receptor activation thresholds in a population of proliferating IgM(+)Nfκb1(-/-)Fo B cells. We demonstrate that p50-NFκB1 represses Il-6 transcription in Fo B cells, with the loss of NFκB1 also resulting in the uncontrolled RELA-driven transcription of Il-6.Collectively, our findings identify a previously unrecognized role for NFκB1 in preventing multiorgan autoimmunity through its negative regulation of Il-6 gene expression in Fo B cells., (© 2016 de Valle et al.)

Progress in understanding humoral immunity has been accelerated by the powerful experimental approaches of genetics, genomics and imaging. Excellent reviews of these advances appeared in 2015 in celebration of the 50th anniversary of the discovery of B cell and T cell lineages in the chicken. Here we provide a contemporary model of B cell differentiation, highlighting recent publications illuminating germinal center (GC), memory B cell and antibody-secreting plasma cell biology. The important contributions of CD4T cells to antibody responses have been thoroughly reviewed elsewhere., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The inhibitor of DNA binding 2 (Id2) is essential for natural killer (NK) cell development with its canonical role being to antagonize E-protein function and alternate lineage fate. Here we have identified a key role for Id2 in regulating interleukin-15 (IL-15) receptor signaling and homeostasis of NK cells by repressing multiple E-protein target genes including Socs3. Id2 deletion in mature NK cells was incompatible with their homeostasis due to impaired IL-15 receptor signaling and metabolic function and this could be rescued by strong IL-15 receptor stimulation or genetic ablation of Socs3. During NK cell maturation, we observed an inverse correlation between E-protein target genes and Id2. These results shift the current paradigm on the role of ID2, indicating that it is required not only to antagonize E-proteins during NK cell commitment, but constantly required to titrate E-protein activity to regulate NK cell fitness and responsiveness to IL-15., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Devil facial tumor disease (DFTD) is a transmissible cancer that has killed most of the Tasmanian devil (Sarcophilus harrissii) population. Since the first case appeared in the mid-1990s, it has spread relentlessly across the Tasmanian devil's geographic range. As Tasmanian devils only exist in Tasmania, Australia, DFTD has the potential to cause extinction of this species. The origin of DFTD was a Schwann cell from a female devil. The disease is transmitted when devils bite each other around the facial areas, a behavior synonymous with this species. Every devil that is 'infected' with DFTD dies from the cancer. Once the DFTD cells have been transmitted, they appear to develop into a cancer without inducing an immune response. The DFTD cancer cells avoid allogeneic recognition because they do not express MHC class I molecules on the cell surface. A reduced genetic diversity and the production of immunosuppressive cytokines may also contribute., (Copyright © 2015 by The American Association of Immunologists, Inc.)

When B cells encounter an antigen, they alter their physiological state and anatomical localization and initiate a differentiation process that ultimately produces antibody-secreting cells (ASCs). We have defined the transcriptomes of many mature B cell populations and stages of plasma cell differentiation in mice. We provide a molecular signature of ASCs that highlights the stark transcriptional divide between B cells and plasma cells and enables the demarcation of ASCs on the basis of location and maturity. Changes in gene expression correlated with cell-division history and the acquisition of permissive histone modifications, and they included many regulators that had not been previously implicated in B cell differentiation. These findings both highlight and expand the core program that guides B cell terminal differentiation and the production of antibodies.