Effector Functions Research Articles

IgG sialylation occurs in B cells pre antibody secretion.

Sialic acids as terminal sugar residues on cell surface or secreted proteins have many functional roles. In particular, the presence or absence of α2,6-linked sialic acid residues at the immunoglobulin G (IgG) Fc fragment can switch IgG effector functions from pro- to anti-inflammatory activity. IgG glycosylation is considered to take place inside the plasma blast/plasma cell while the molecule travels through the endoplasmic reticulum and Golgi apparatus before being secreted. However, more recent studies have suggested that IgG sialylation may occur predominantly post-antibody secretion. To what extent this extracellular IgG sialylation process contributes to overall IgG sialylation remains unclear, however. By generating bone marrow chimeric mice with a B cell-specific deletion of ST6Gal1, the key enzyme required for IgG sialylation, we now show that sialylation of the IgG Fc fragment exclusively occurs within B cells pre-IgG secretion. We further demonstrate that B cells expressing ST6Gal1 have a developmental advantage over B cells lacking ST6Gal1 expression and thus dominate the plasma cell pool and the resulting serum IgG population in mouse models in which both ST6Gal1-sufficient and -deficient B cells are present.

Exploiting bacterial effector proteins to uncover evolutionarily conserved antiviral host machinery.

Arboviruses are a diverse group of insect-transmitted pathogens that pose global public health challenges. Identifying evolutionarily conserved host factors that combat arbovirus replication in disparate eukaryotic hosts is important as they may tip the balance between productive and abortive viral replication, and thus determine virus host range. Here, we exploit naturally abortive arbovirus infections that we identified in lepidopteran cells and use bacterial effector proteins to uncover host factors restricting arbovirus replication. Bacterial effectors are proteins secreted by pathogenic bacteria into eukaryotic hosts cells that can inhibit antimicrobial defenses. Since bacteria and viruses can encounter common host defenses, we hypothesized that some bacterial effectors may inhibit host factors that restrict arbovirus replication in lepidopteran cells. Thus, we used bacterial effectors as molecular tools to identify host factors that restrict four distinct arboviruses in lepidopteran cells. By screening 210 effectors encoded by seven different bacterial pathogens, we identify several effectors that individually rescue the replication of all four arboviruses. We show that these effectors encode diverse enzymatic activities that are required to break arbovirus restriction. We further characterize Shigella flexneri-encoded IpaH4 as an E3 ubiquitin ligase that directly ubiquitinates two evolutionarily conserved proteins, SHOC2 and PSMC1, promoting their degradation in insect and human cells. We show that depletion of either SHOC2 or PSMC1 in insect or human cells promotes arbovirus replication, indicating that these are ancient virus restriction factors conserved across invertebrate and vertebrate hosts. Collectively, our study reveals a novel pathogen-guided approach to identify conserved antimicrobial machinery, new effector functions, and conserved roles for SHOC2 and PSMC1 in virus restriction.

Comprehensive analysis and characterization of glycan pairing in therapeutic antibodies and Fc-containing biotherapeutics: Addressing current limitations and implications for N-glycan impact

N-glycosylation of the Fc part is a (critical) quality attribute of therapeutic antibodies and Fc-containing biotherapeutics, that impacts their stability, immunogenicity, pharmacokinetics, and effector functions. Current glycosylation analysis methods focus on the absolute amounts of glycans, neglecting the apparent glycan distribution over the entirety of proteins. The combination of the two Fc N-glycans, herein referred to as glyco-pair, therefore remains unknown, which is a major drawback for N-glycan impact assessment. This study presents a comprehensive workflow for the analysis and characterization of Fc N-glycan pairing in biotherapeutics, addressing the limitations of current glycosylation analysis methods. The applicability of the method across various biotherapeutic proteins including antibodies, bispecific antibody formats, and a Fc-Fusion protein is demonstrated, and the impact of method conditions on glycan pairing analysis is highlighted. Moreover, the influence of the molecular format, Fc backbone, production process, and cell line on glycan pairing pattern was investigated. The results underscore the significance of comprehensive glycan pairing analysis to accurately assess the impact of N-glycans on important product quality attributes of therapeutic antibodies and Fc-containing biotherapeutics.

The cell cycle regulator p16 promotes tumor infiltrated CD8+ T cell exhaustion and apoptosis

The therapeutic efficacy of adoptive T cell therapy is largely restricted by reduced viability and dysfunction of CD8+ T cells. Continuous antigen stimulation disrupts the expansion, effector function, and metabolic fitness of CD8+ T cells, leading to their differentiation into an exhausted state within the tumor microenvironment (TME). While the function of the cell cycle negative regulator p16 in senescent cells is well understood, its role in T cell exhaustion remains unclear. In this study, we demonstrated that TCR stimulation of CD8+ T cells rapidly upregulates p16 expression, with its levels positively correlating with TCR affinity. Chronic TCR stimulation further increased p16 expression, leading to CD8+ T cell apoptosis and exhaustion differentiation, without inducing DNA damage or cell senescence. Mechanistic investigations revealed that p16 downregulates mTOR, glycolysis, and oxidative phosphorylation (OXPHOS) associated gene expression, resulting in impaired mitochondrial fitness, reduced T cell viability, and diminished effector function. Furthermore, the deletion of p16 significantly enhances the persistence of CD8+ T cells within tumors and suppresses the terminal exhaustion of tumor-infiltrating T cells. Overall, our findings elucidate how increased p16 expression reshapes T cell intracellular metabolism, drives T cell apoptosis and exhaustion differentiation, and ultimately impairs T cell anti-tumor function.

GPC3-targeted CAR-T cells expressing GLUT1 or AGK exhibit enhanced antitumor activity against hepatocellular carcinoma.

Chimeric antigen receptor-expressing T (CAR-T) cells induce robust antitumor responses in patients with hematologic malignancies. However, CAR-T cells exhibit only limited efficacy against solid tumors such as hepatocellular carcinoma (HCC), partially due to their limited expansion and persistence. CD8+ T cells, as key components of the adaptive immune response, play a central role in antitumor immunity. Aerobic glycolysis is the main metabolic feature of activated CD8+ T cells. In the tumor microenvironment, however, the uptake of large amounts of glucose by tumor cells and other immunosuppressive cells can impair the activation of T cells. Only when tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment have a glycolytic advantage might the effector function of T cells be activated. Glucose transporter type 1 (GLUT1) and acylglycerol kinase (AGK) can boost glycolytic metabolism and activate the effector function of CD8+T cells, respectively. In this study, we generated GPC3-targeted CAR-T cells overexpressing GLUT1 or AGK for the treatment of HCC. GPC3-targeted CAR-T cells overexpressing GLUT1 or AGK specifically and effectively lysed GPC3-positive tumor cells in vitro in an antigen-dependent manner. Furthermore, GLUT1 or AGK overexpression protected CAR-T cells from apoptosis during repeated exposures to tumor cells. Compared with second-generation CAR-T cells, GPC3-targeted CAR-T cells overexpressing GLUT1 or AGK exhibited greater CD8+ T-cell persistence in vivo and better antitumor effects in HCC allograft mouse models. Finally, we revealed that GLUT1 or AGK maintained anti-apoptosis ability in CD8+ T cells via activation of the PI3K/Akt pathway. This finding might identify a therapeutic strategy for advanced HCC.

Platelet-derived major histocompatibility complex class I coating on Treponema pallidum attenuates natural killer cell lethality

ABSTRACT The evasive tactics of Treponema pallidum pose a major challenge in combating and eradicating syphilis. Natural killer (NK) cells mediate important effector functions in the control of pathogenic infection, preferentially eliminating targets with low or no expression of major histocompatibility complex (MHC) class I. To clarify T. pallidum’s mechanisms in evading NK-mediated immunosurveillance, experiments were performed to explore the cross-talk relations among T. pallidum, NK cells, and platelets. T. pallidum adhered to, activated, and promoted particle secretion of platelets. After preincubation with T. pallidum, platelets expressed and secreted high levels of MHC class I, subsequently transferring them to the surface of T. pallidum, potentially inducing an immune phenotype characterized by the “pseudo-expression” of MHC class I on the surface of T. pallidum (hereafter referred to a “pseudo-expression” of MHC class I). The polA mRNA assay showed that platelet-preincubated T. pallidum group exhibited a significantly higher copy number of polA transcript than the T. pallidum group. The survival rate of T. pallidum mirrored that of polA mRNA, indicating that preincubation of T. pallidum with platelets attenuated NK cell lethality. Platelets pseudo-expressed the MHC class I ligand on the T. pallidum surface, facilitating binding to killer cell immunoglobulin-like receptors with two immunoglobulin domains and long cytoplasmic tail 3 (KIR2DL3) on NK cells and initiating dephosphorylation of Vav1 and phosphorylation of Crk, ultimately attenuating NK cell lethality. Our findings elucidate the mechanism by which platelets transfer MHC class I to the T. pallidum surface to evade NK cell immune clearance.

CAR T cells outperform CAR NK cells in CAR-mediated effector functions in head-to-head comparison

BackgroundCAR NK cells as vehicles for engineered “off-the-shelf” cellular cancer immunotherapy have attracted significant interest. Nonetheless, a comprehensive comparative assessment of the anticancer activity of CAR T cells and CAR NK cells carrying approved benchmark anti-CD19 CAR constructs is missing. Here, we report a direct head-to-head comparison of CD19-directed human T and NK cells.MethodsWe generated CAR T and CAR NK cells derived from healthy donor PBMC by retroviral transduction with the same benchmark second-generation anti-CD19 CAR construct, FMC63.28z. We investigated IFN-γ secretion and direct cytotoxicity in vitro against various CD19+ cancer cell lines as well as in autologous versus allogeneic settings. Furthermore, we have assessed anticancer activity of CAR T and CAR NK cells in vivo using a xenograft lymphoma model in an autologous versus allogeneic setting and a leukemia model.ResultsOur main findings are a drastically reduced capacity for CAR-mediated IFN-γ production and lower CAR-mediated cytotoxicity of CAR NK cells relative to CAR T cells in vitro. Consistent with these in vitro findings, we report superior anticancer activity of autologous CAR T cells compared with allogeneic CAR NK cells in vivo.ConclusionsCAR T cells had significantly higher CAR-mediated effector functions than CAR NK cells in vitro against several cancer cell lines and autologous CAR T cells outperformed allogeneic CAR NK cells both in vitro and in vivo. CAR NK cells will likely benefit from further engineering to enhance anticancer activity to ultimately fulfill the promise of an effective off-the-shelf product.

Longitudinal Analysis of Nursing Home Residents' T-Cell Responses After SARS-CoV-2 mRNA Vaccinations Shows Influence of Biological Sex and Infection History.

Vaccines and vaccine boosting have blunted excess morbidity and mortality from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in older nursing home residents (NHR). However, the impact of repeated vaccination on the T-cell response based on biological sex and prior infection of NHR remain understudied. We examined T-cell responses to SARS-CoV-2 mRNA vaccines in a cohort of NHR and healthcare workers (HCW) over 2 years. We used interferon-γ ELIspot and flow cytometry to assess T-cell response before, 2 weeks, and 6 months after the initial series and each of 2 booster vaccines. We analyzed these data longitudinally with mixed-effect modeling and also examined subsets of our cohorts for additional changes in T-cell effector function. Prior SARS-CoV-2 infection and female sex contributed to higher T-cell response in NHR but not HCW. When looking across time points, NHR but not HCW with prior infection had significantly higher T-cell responses than infection-naive subjects. These patterns of response were maintained across multiple booster vaccinations. These results suggest that the age, multimorbidity, and/or frailty of the NHR cohort may accentuate sex and infection status differences in T-cell response to mRNA vaccination.

Tuft cell acetylcholine is released into the gut lumen to promote anti-helminth immunity

Upon parasitic helminth infection, activated intestinal tuft cells secrete interleukin-25 (IL-25), which initiates a type 2 immune response during which lamina propria type 2 innate lymphoid cells (ILC2s) produce IL-13. This causes epithelial remodeling, including tuft cell hyperplasia, the function of which is unknown. We identified a cholinergic effector function of tuft cells, which are the only epithelial cells that expressed choline acetyltransferase (ChAT). During parasite infection, mice with epithelial-specific deletion of ChAT had increased worm burden, fitness, and fecal egg counts, even though type 2 immune responses were comparable. Mechanistically, IL-13-amplified tuft cells release acetylcholine (ACh) into the gut lumen. Finally, we demonstrated a direct effect of ACh on worms, which reduced their fecundity via helminth-expressed muscarinic ACh receptors. Thus, tuft cells are sentinels in naive mice, and their amplification upon helminth infection provides an additional type 2 immune response effector function.

Shedding light on GPIbα shedding.

Ectodomain shedding has been investigated since the late 1980s. The abundant and platelet specific GPIbα receptor is cleaved by ADAM17 resulting in the release of its ectodomain called glycocalicin. This review will address the role of glycocalicin as an end-stage marker of platelet turnover and storage lesion and will consider a potential function as effector in processes beyond hemostasis. Glycocalicin has been described as a marker for platelet senescence, turnover and storage lesion but is not routinely used in a clinical setting because its diagnostic value is nondiscriminatory. Inhibition of glycocalicin shedding improves posttransfusion recovery but little is known (yet) about potential hemostatic improvements. In physiological settings, GPIbα shedding is restricted to the intracellular GPIbα receptor subpopulation suggesting a role for shedding or glycocalicin beyond hemostasis. So far, all evidence represents glycocalicin as an end-stage biomarker of platelet senescence and a potential trigger for platelet clearance. The extensive list of interaction partners of GPIbα in fields beyond hemostasis opens new possibilities to investigate specific effector functions of glycocalicin.

Exploring the therapeutic opportunities of potassium channels for the treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the synovial joint, which leads to inflammation, loss of function, joint destruction, and disability. The disease biology of RA involves complex interactions between genetic and environmental factors and is strongly associated with various immune cells, and each of the cell types contributes differently to disease pathogenesis. Several immunomodulatory molecules, such as cytokines, are secreted from the immune cells and intervene in the pathogenesis of RA. In immune cells, membrane proteins such as ion channels and transporters mediate the transport of charged ions to regulate intracellular signaling pathways. Ion channels control the membrane potential and effector functions such as cytotoxic activity. Moreover, clinical studies investigating patients with mutations and alterations in ion channels and transporters revealed their importance in effective immune responses. Recent studies have shown that voltage-gated potassium channels and calcium-activated potassium channels and their subtypes are involved in the regulation of immune cells and RA. Due to the role of these channels in the pathogenesis of RA and from multiple pieces of clinical evidence, they can be considered therapeutic targets for the treatment of RA. Here, we describe the role of voltage-gated and calcium-activated potassium channels and their subtypes in RA and their pharmacological application as drug targets.

Fate control engagement augments NK cell responses in LV/hu-IL-12 transduced sarcoma

IntroductionNK cells are an untapped resource for cancer therapy. Sarcomas transduced with lentiviruses to express human IL-12 are only cleared in mice bearing mature human NK cells. However, systemic inflammation limits IL-12 utilization. Fate control a.k.a. “suicide mechanisms” regulate unchecked systemic inflammation caused by cellular immunotherapies. Despite increasing utilization, there remains limited data on immune consequences or tumor-directed effects of fate control. ObjectivesWe sought to engage the mutant thymidylate kinase (mTMPK) metabolic fate control system to regulate systemic inflammation and assess the impact on NK cell effector functions. MethodsPrimary human sarcoma short-passage samples and cell lines were transduced with LV/hu-IL-12_mTMPK engineering expression of IL-12 and an AZT-associated fate control enzyme. We assessed transduced sarcoma responses to AZT engagement and subsequent modulation of NK cell functions as measured by inflammatory cytokine production and cytotoxicity. ResultsAZT administration to transduced (LV/hu-IL-12_mTMPK) short-passage primary human sarcomas and human Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma cell lines, abrogated the robust expression of human IL-12. Fate control activation elicited a specific dose-dependent cytotoxic effect measured by metabolic activity (WST-1) and cell death (Incucyte). NK effector functions of IFN-γ and cytotoxic granule release were significantly augmented despite IL-12 abrogation. This correlated with preferentially induced expression of NK cell activation ligands. ConclusionsmTMPK fate control engagement terminates transduced sarcoma IL-12 production and triggers cell death, but also augments an NK cell-mediated response coinciding with metabolic stress activating surface ligand induction. Fate control engagement could offer a novel immune activation method for NK cell-mediated cancer clearance.

Expression of CD39 is associated with T cell exhaustion in ovarian cancer and its blockade reverts T cell dysfunction

ABSTRACT Immune exhaustion is a hallmark of ovarian cancer. Using multiparametric flow cytometry, the study aimed to analyze protein expression of novel immunological targets on CD3+ T cells isolated from the peripheral blood (n = 20), malignant ascites (n = 16), and tumor tissue (n = 6) of patients with ovarian cancer (OVCA). The study revealed an increased proportion of effector memory CD8+ T cells in OVCA tissue and malignant ascites. An OVCA-characteristic PD-1high CD8+ T cell population was detected, which differed from PD-1lowCD8+ T cells by increased co-expression of TIGIT, CD39, and HLA-DR. In addition, these OVCA-characteristic CD8+ T cells showed reduced expression of the transcription factor TCF-1, which may also indicate reduced effector function and memory formation. On the contrary, the transcription factor TOX, which significantly regulates terminal T cell-exhaustion, was found more frequently in these cells. Further protein and gene analysis showed that CD39 and CD73 were also expressed on OVCA tumor cells isolated from solid tumors (n = 14) and malignant ascites (n = 9). In the latter compartment, CD39 and CD73 were also associated with the expression of the “don’t eat me” molecule CD24 on tumor cells. Additionally, ascites-derived CD24+EpCAM+ tumor cells showed a higher frequency of CD39+ or CD73+ cells. Furthermore, CD39 expression was associated with unfavorable clinical parameters. Expression of CD39 on T cells was upregulated through CD3/CD28 stimulation and its blockade by a newly developed nanobody construct resulted in increased proliferation (eFluor), activation (CD25 and CD134), and production of cytotoxic cytokines (IFN-γ, TNF-α, and granzyme-B) of CD8+ T cells.

Iron controls the development of airway hyperreactivity by regulating ILC2 metabolism and effector function.

Group 2 innate lymphoid cells (ILC2s) rapidly induce a type 2 inflammation in the lungs in response to allergens. Here, we focused on the role of iron, a critical nutritional trace element, on ILC2 function and asthma pathogenesis. We found that transferrin receptor 1 (TfR1) is rapidly up-regulated and functional during ILC2 activation in the lungs, and blocking transferrin uptake reduces ILC2 expansion and activation. Iron deprivation reprogrammed ILC2 metabolism, inducing a HIF-1α-driven up-regulation of glycolysis and inhibition of oxidative mitochondrial activity. Consequently, we observed that in vivo iron chelation or induction of hypoferremia reduced the development of airway hyperreactivity in experimental models of ILC2-driven allergic asthma. Human circulating ILC2s rapidly induced TfR1 during activation, whereas inhibition of iron uptake or iron deprivation reduced effector functions. Last, we found a negative relationship between circulating ILC2 TfR1 expression and airway function in cohorts of patients with asthma. Collectively, our studies define cellular iron as a critical regulator of ILC2 function.

Genome-Informed Trophic Classification and Functional Characterization of Virulence Proteins from the Maize Tar Spot Pathogen Phyllachora maydis.

Phyllachora maydis is an ascomycete foliar fungal pathogen and the causal agent of tar spot in maize. Although P. maydis is considered an economically important foliar pathogen of maize, our general knowledge of the trophic lifestyle and functional role of effector proteins from this fungal pathogen remains limited. Here, we utilized a genome-informed approach to predict the trophic lifestyle of P. maydis and functionally characterized a subset of candidate effectors from this fungal pathogen. Leveraging the most recent P. maydis genome annotation and the CATAStrophy pipeline, we show that this fungal pathogen encodes a predicted carbohydrate-active enzymes (CAZymes) repertoire consistent with that of biotrophs. To investigate fungal pathogenicity, we selected 18 candidate effector proteins that were previously shown to be expressed during primary disease development. We assessed whether these putative effectors share predicted structural similarity with other characterized fungal effectors and determined whether any suppress plant immune responses. Using AlphaFold2 and Foldseek, we showed that one candidate effector, PM02_g1115, adopts a predicted protein structure similar to that of an effector from Verticillium dahlia. Furthermore, transient expression of candidate effector-fluorescent protein fusions in Nicotiana benthamiana revealed two putative effectors, PM02_g378 and PM02_g2610, accumulated predominantly in the cytosol, and three candidate effectors, PM02_g1115, PM02_g7882, and PM02_g8240, consistently attenuated chitin-mediated reactive oxygen species production. Collectively, the results presented herein provide insights into the predicted trophic lifestyle and putative functions of effectors from P. maydis and will likely stimulate continued research to elucidate the molecular mechanisms used by P. maydis to induce tar spot.

Atypical chemokine receptors in the immune system.

Leukocyte migration is a fundamental component of innate and adaptive immune responses as it governs the recruitment and localization of these motile cells, which is crucial for immune cell priming, effector functions, memory responses and immune regulation. This complex cellular trafficking system is controlled to a large extent via highly regulated production of secreted chemokines and the restricted expression of their membrane-tethered G-protein-coupled receptors. The activity of chemokines and their receptors is also regulated by a subfamily of molecules known as atypical chemokine receptors (ACKRs), which are chemokine receptor-like molecules that do not couple to the classical signalling pathways that promote cell migration in response to chemokine ligation. There has been a great deal of progress in understanding the biology of these receptors and their functions in the immune system in the past decade. Here, we describe the contribution of the various ACKRs to innate and adaptive immune responses, focussing specifically on recent progress. This includes recent findings that have defined the role for ACKRs in sculpting extracellular chemokine gradients, findings that broaden the spectrum of chemokine ligands recognized by these receptors, candidate new additions to ACKR family, and our increasing understanding of the role of these receptors in shaping the migration of innate and adaptive immune cells.

Characteristics of T Cells in Single-Cell Datasets of Peripheral Blood and Cerebrospinal Fluid in Alzheimer's Disease Patients.

Alzheimer's disease (AD) is the most common type of dementia, causing a huge socioeconomic burden. In parallel with the widespread uptake of single-cell RNA sequencing (scRNA-seq) technology, there has been a rapid accumulation of data produced by researching AD at single-cell resolution, which is more conductive to explore the neuroimmune-related mechanism of AD. To explore the potential features of T cells in the peripheral blood and cerebrospinal fluid of AD patients. Two datasets, GSE181279 and GSE134578, were integrated from GEO database. Seurat, Monocle, CellChat, scRepertoire, and singleR packages were mainly employed for data analysis. Our analysis demonstrated that in peripheral blood, T cells were significantly expanded, and these expanded T cells were possessed effector function, such as CD8+TEMRA, CD4+TEMRA, and CD8+TEM. Interestingly, CD8+TEMRA and CD4+TEMRA cells positioned adjacently after dimensions reduction and clustering. Notably, we identified that the expanded T cells were developed from Naïve T cells and TCM cells, and TEM cells was in the intermediate state of this developing process. Additionally, in cerebrospinal fluid of AD patients, the amplified T cells were mainly CD8+TEMRA cells, and the number and strength of communication between CD4+TEM, CD8+TEM, and CD8+TEMRA were decreased in AD patients. Our comprehensive analyses identified the cells in cerebrospinal fluid from AD patients are expanded TEMRA or TEM cells and the TEMRA cells communicating with other immune cells is weakened, which may be an important immune feature that leads to AD.

ABBV-319: a CD19-targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies

AbstractGlucocorticoids are key components of the standard-of-care treatment regimens for B-cell malignancy. However, systemic glucocorticoid treatment is associated with several adverse events. ABBV-319 is a CD19-targeting antibody-drug conjugate engineered to reduce glucocorticoid-associated toxicities while possessing 3 distinct mechanisms of action (MOA) to increase therapeutic efficacy: (1) antibody-mediated delivery of a glucocorticoid receptor modulator (GRM) payload to activate apoptosis, (2) inhibition of CD19 signaling, and (3) enhanced fragment crystallizable (Fc)–mediated effector function via afucosylation of the antibody backbone. ABBV-319 elicited potent GRM-driven antitumor activity against multiple malignant B-cell lines in vitro, as well as in cell line-derived xenografts and patient-derived xenografts (PDXs) in vivo. Remarkably, a single dose of ABBV-319 induced sustained tumor regression and enhanced antitumor activity compared with repeated dosing of systemic prednisolone at the maximum tolerated dose in mice. The unconjugated CD19 monoclonal antibody (mAb) also displayed antiproliferative activity in a subset of B-cell lymphoma cell lines through the inhibition of phosphoinositide 3-kinase signaling. Moreover, afucosylation of CD19 mAb enhanced Fc-mediated antibody-dependent cellular cytotoxicity. Notably, ABBV-319 displayed superior efficacy compared with afucosylated CD19 mAb in human CD34+ peripheral blood mononuclear cell–engrafted NSG-Tg(Hu-IL15) transgenic mice, demonstrating enhanced antitumor activity when multiple MOAs are enabled. ABBV-319 also showed durable antitumor activity across multiple B-cell lymphoma PDX models, including nongerminal center B-cell diffuse large B-cell lymphoma and relapsed lymphoma after R-CHOP treatment. Collectively, these data support the ongoing evaluation of ABBV-319 in a phase 1 clinical trial.

Pro- or anti-inflammatory properties of cytokines in COVID-19: which offer better protection against disease?

Pro- or anti-inflammatory properties of cytokines in COVID-19: which offer better protection against disease I read the article by Al-Mquter et al. that compared circulating levels of 3 cytokines(IL-6, IL-25 and IL-35) amongst healthy controls(HC) and patients with COVID-19. They reported a significant increase in the serum concentration of these cytokines in patients versus HC(1). Their results confirmed again that assessment of cytokine profiles could be used as COVID-19 markers and may also provide practical implications for disease treatment. Nonetheless, understanding the role of cytokines in COVID-19 is complicated because of the complex nature of cytokine networks and the pathogenesis of COVID-19(2). IL-6 is one of the first cytokines produced during COVID-19 and increasing evidence suggests that its alteration may be associated with disease outcome. IL-6 is a pleotropic cytokine and has both pro- and anti- inflammatory effects. Therefore, it appears to operate in protective or pathological immunity to COVID-19. IL-6 can promote immune processes associated with resistance to different pathogens including COVID-19. It contributes to host defense via different pathways, including the stimulation of acute phase responses and hematopoiesis. Nonetheless, dysregulated and persistent synthesis of IL-6 can be resulted to the onset and development of pathological conditions. These different effector functions may be associated with different concentration of IL-6 that may result from different signaling pathwaysIL-6 signaling includes at least three distinct pathways: cis-signalling; trans-signalling and trans-presentation. It seems that IL-6 trans-signalling and trans-presentation are probably responsible for severe progressive COVID-19. These signaling pathways can trigger diffuse inflammation at various levels. Conversely, IL-6 cis-signalling mediates negative feedback mechanisms on proinflammatory cytokines, including suppression of their production, stimulation of their decoy receptors, and inhibition the maturation of Th17 cells. Circulatory IL-6 in COVID-19 patients reaches the peak level at advanced stages around two weeks of disease. Elevated IL-6 (e.g., > 100-120 pg/mL) levels in critical COVID-19 may reflect augmented IL-6 cis-signalling in an attempt to exert homeostatic functions, although there is no general consensus on this issue(3).

KMT2D regulates activation, localization, and integrin expression by T-cells.

Individuals with Kabuki syndrome present with immunodeficiency; however, how pathogenic variants in the gene encoding the histone-modifying enzyme lysine methyltransferase 2D (KMT2D) lead to immune alterations remain poorly understood. Following up on our prior report of KMT2D-altered integrin expression in B-cells, we performed targeted analyses of KMT2D's influence on integrin expression in T-cells throughout development (thymocytes through peripheral T-cells) in murine cells with constitutive- and conditional-targeted Kmt2d deletion. Using high-throughput RNA-sequencing and flow cytometry, we reveal decreased expression (both at the transcriptional and translational levels) of a cluster of leukocyte-specific integrins, which perturb aspects of T-cell activation, maturation, adhesion/localization, and effector function. H3K4me3 ChIP-PCR suggests that these evolutionary similar integrins are under direct control of KMT2D. KMT2D loss also alters multiple downstream programming/signaling pathways, including integrin-based localization, which can influence T-cell populations. We further demonstrated that KMT2D deficiency is associated with the accumulation of murine CD8+ single-positive (SP) thymocytes and shifts in both human and murine peripheral T-cell populations, including the reduction of the CD4+ recent thymic emigrant (RTE) population. Together, these data show that the targeted loss of Kmt2d in the T-cell lineage recapitulates several distinct features of Kabuki syndrome-associated immune deficiency and implicates epigenetic mechanisms in the regulation of integrin signaling.