Microbiota-Induced Type I Interferons Instruct a Poised Basal State of Dendritic Cells.

Environmental signals shape host physiology and fitness. Microbiota-derived cues are required to program conventional dendritic cells (cDCs) during the steady state so that they can promptly respond and initiate adaptive immune responses when encountering pathogens. However, the molecular underpinnings of microbiota-guided instructive programs are not well understood. Here, we report that the indigenous microbiota controls constitutive production of type I interferons (IFN-I) by plasmacytoid DCs. Using genome-wide analysis of transcriptional and epigenetic regulomes of cDCs from germ-free and IFN-I receptor (IFNAR)-deficient mice, we found that tonic IFNAR signaling instructs a specific epigenomic and metabolic basal state that poises cDCs for future pathogen combat. However, such beneficial biological function comes with a trade-off. Instructed cDCs can prime T cell responses against harmless peripheral antigens when removing roadblocks of peripheral tolerance. Our data provide fresh insights into the evolutionary trade-offs that come with successful adaptation of vertebrates to their microbial environment.

Protein kinase CK2 enables regulatory T cells to suppress excessive TH2 responses in vivo.

The quality of the adaptive immune response depends on the differentiation of distinct CD4(+) helper T cell subsets, and the magnitude of an immune response is controlled by CD4(+)Foxp3(+) regulatory T cells (Treg cells). However, how a tissue- and cell type-specific suppressor program of Treg cells is mechanistically orchestrated has remained largely unexplored. Through the use of Treg cell-specific gene targeting, we found that the suppression of allergic immune responses in the lungs mediated by T helper type 2 (TH2) cells was dependent on the activity of the protein kinase CK2. Genetic ablation of the ß-subunit of CK2 specifically in Treg cells resulted in the proliferation of a hitherto-unexplored ILT3(+) Treg cell subpopulation that was unable to control the maturation of IRF4(+)PD-L2(+) dendritic cells required for the development of TH2 responses in vivo.

Targeting the tissue factor coagulation initiation complex prevents antiphospholipid antibody development.

ABSTRACT: Antiphospholipid antibodies (aPL) in primary or secondary antiphospholipid syndrome (APS) are a major cause for acquired thrombophilia, but specific interventions preventing autoimmune aPL development are an unmet clinical need. Although autoimmune aPL cross react with various coagulation regulatory proteins, lipid-reactive aPL, including those derived from patients with COVID-19, recognize the endolysosomal phospholipid lysobisphosphatidic acid presented by the cell surface-expressed endothelial protein C receptor. This specific recognition leads to complement-mediated activation of tissue factor (TF)-dependent proinflammatory signaling and thrombosis. Here, we show that specific inhibition of the TF coagulation initiation complex with nematode anticoagulant protein c2 (NAPc2) prevents the prothrombotic effects of aPL derived from patients with COVID-19 in mice and the aPL-induced proinflammatory and prothrombotic activation of monocytes. The induction of experimental APS is dependent on the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex, and NAPc2 suppresses monocyte endosomal reactive oxygen species production requiring the TF cytoplasmic domain and interferon-α secretion from dendritic cells. Latent infection with murine cytomegalovirus causes TF cytoplasmic domain-dependent development of persistent aPL and circulating phospholipid-reactive B1 cells, which is prevented by short-term intervention with NAPc2 during acute viral infection. In addition, treatment of lupus prone MRL-lpr mice with NAPc2, but not with heparin, suppresses dendritic-cell activation in the spleen, aPL production and circulating phospholipid-reactive B1 cells, and attenuates lupus pathology. These data demonstrate a convergent TF-dependent mechanism of aPL development in latent viral infection and autoimmune disease and provide initial evidence that specific targeting of the TF initiation complex has therapeutic benefits beyond currently used clinical anticoagulant strategies.

Cross-presenting Langerhans cells are required for the early reactivation of resident CD8+ memory T cells in the epidermis.

Tissue-resident memory CD8+ T cells (TRM) reside at sites of previous infection, providing protection against reinfection with the same pathogen. In the skin, TRM patrol the epidermis, where keratinocytes are the entry site for many viral infections. Epidermal TRM react rapidly to cognate antigen encounter with the secretion of cytokines and differentiation into cytotoxic effector cells, constituting a first line of defense against skin reinfection. Despite the important protective role of skin TRM, it has remained unclear, whether their reactivation requires a professional antigen-presenting cell (APC). We show here, using a model system that allows antigen targeting selectively to keratinocytes in a defined area of the skin, that limited antigen expression by keratinocytes results in rapid, antigen-specific reactivation of skin TRM. Our data identify epidermal Langerhans cells that cross-present keratinocyte-derived antigens, as the professional APC indispensable for the early reactivation of TRM in the epidermal layer of the skin.

[Immunological foundations of neurological diseases]. / Immunologische Grundlagen neurologischer Erkrankungen.

BACKGROUND: Neurodegenerative diseases represent an increasing challenge in ageing societies, as only limited treatment options are currently available. OBJECTIVE: New research methods and interdisciplinary interaction of different disciplines have changed the way neurological disorders are viewed and paved the way for the comparatively new field of neuroimmunology, which was established in the early 1980s. Starting from neurological autoimmune diseases, such as multiple sclerosis, knowledge about the involvement of immunological processes in other contexts, such as stroke or traumatic brain injury, has been significantly expanded in recent years. MATERIAL AND METHODS: This review article provides an overview of the role of the immune system and the resulting potential for novel treatment approaches. RESULTS: The immune system plays a central role in fighting infections but is also able to react to the body's own signals under sterile conditions and cause inflammation and subsequent adaptive immune responses through the release of immune mediators and the recruitment and differentiation of certain immune cell types. This can be beneficial in initiating healing processes; however, chronic inflammatory conditions usually have destructive consequences for the tissue and the organism and must be interrupted. CONCLUSION: It is now known that different cells of the immune system play an important role in neurological diseases. Regulatory mechanisms, which are mediated by regulatory T cells or Th2 cells, are usually associated with a good prognosis, whereas inflammatory processes and polarization towards Th1 or Th17 have a destructive character. Novel immunomodulators, which are also increasingly being used in cancer treatment, can now be used in a tissue-specific manner and therefore offer great potential for use in neurological diseases.

Peptide-Decorated Degradable Polycarbonate Nanogels for Eliciting Antigen-Specific Immune Responses.

For successful therapeutic interventions in cancer immunotherapy, strong antigen-specific immune responses are required. To this end, immunostimulating cues must be combined with antigens to simultaneously arrive at antigen-presenting cells and initiate cellular immune responses. Recently, imidazoquinolines have shown their vast potential as small molecular Toll-like receptor 7/8 (TLR7/8) agonists for immunostimulation when delivered by nanocarriers. At the same time, peptide antigens are promising antigen candidates but require combination with immune-stimulating adjuvants to boost their immunogenicity and exploit their full potential. Consequently, we herein present biodegradable polycarbonate nanogels as versatile delivery system for adjuvants within the particles' core as well as for peptide antigens by surface decoration. For that purpose, orthogonally addressable multifunctional polycarbonate block copolymers were synthesized, enabling adjuvant conjugation through reactive ester chemistry and peptide decoration by strain-promoted alkyne-azide cycloaddition (SPAAC). In preparation for SPAAC, CD4+-specific peptide sequences of the model protein antigen ovalbumin were equipped with DBCO-moieties by site-selective modification at their N-terminal cysteine. With their azide groups exposed on their surface, the adjuvant-loaded nanogels were then efficiently decorated with DBCO-functional CD4+-peptides by SPAAC. In vitro evaluation of the adjuvant-loaded peptide-decorated gels then confirmed their strong immunostimulating properties as well as their high biocompatibility. Despite their covalent conjugation, the CD4+-peptide-decorated nanogels led to maturation of primary antigen-presenting cells and the downstream priming of CD4+-T cells. Subsequently, the peptide-decorated nanogels loaded with TLR7/8 agonist were successfully processed by antigen-presenting cells, enabling potent immune responses for future application in antigen-specific cancer immunotherapy.

End Group Dye-Labeled Polycarbonate Block Copolymers for Micellar (Immuno-)Drug Delivery.

Defined conjugation of functional molecules to block copolymer end groups is a powerful strategy to enhance the scope of micellar carriers for drug delivery. In this study, an approach to access well-defined polycarbonate-based block copolymers by labeling their end groups with single fluorescent dye molecules is established. Following controlled polymerization conditions, the block copolymers' primary hydroxy end group can be converted into activated pentafluorophenyl ester carbonates and subsequently aminolyzed with fluorescent dyes that are equipped with primary amines. During a solvent-evaporation process, the resulting end group dye-labeled block copolymers self-assemble into narrowly dispersed ∼25 nm-sized micelles and simultaneously encapsulate hydrophobic (immuno-)drugs. The covalently attached fluorescent tracer can be used to monitor both uptake into cells and stability under biologically relevant conditions, including incubation with blood plasma or during blood circulation in zebrafish embryos. By encapsulation of the toll-like receptor 7/8 (TLR7/8) agonist CL075, immune stimulatory polymeric micelles are generated that get internalized by various antigen-presenting dendritic cells and promote their maturation. Generally, such end group dye-labeled polycarbonate block copolymers display ideal features to permit targeted delivery of hydrophobic drugs to key immune cells for vaccination and cancer immunotherapy.

Antigen processing influences HIV-specific cytotoxic T lymphocyte immunodominance.

Although cytotoxic T lymphocytes (CTLs) in people infected with human immunodeficiency virus type 1 can potentially target multiple virus epitopes, the same few are recognized repeatedly. We show here that CTL immunodominance in regions of the human immunodeficiency virus type 1 group-associated antigen proteins p17 and p24 correlated with epitope abundance, which was strongly influenced by proteasomal digestion profiles, affinity for the transporter protein TAP, and trimming mediated by the endoplasmatic reticulum aminopeptidase ERAAP, and was moderately influenced by HLA affinity. Structural and functional analyses demonstrated that proteasomal cleavage 'preferences' modulated the number and length of epitope-containing peptides, thereby affecting the response avidity and clonality of T cells. Cleavage patterns were affected by both flanking and intraepitope CTL-escape mutations. Our analyses show that antigen processing shapes CTL response hierarchies and that viral evolution modifies cleavage patterns and suggest strategies for in vitro vaccine optimization.

Transcutaneous immunization with CD40 ligation boosts cytotoxic T lymphocyte mediated antitumor immunity independent of CD4 helper cells in mice.

Transcutaneous immunization (TCI) is a novel vaccination strategy that utilizes skin-associated lymphatic tissue to induce immune responses. Employing T-cell epitopes and the TLR7 agonist imiquimod onto intact skin mounts strong primary, but limited memory CTL responses. To overcome this limitation, we developed a novel imiquimod-containing vaccination platform (IMI-Sol) rendering superior primary CD8+ and CD4+ T-cell responses. However, it has been unclear whether IMI-Sol per se is restricted in terms of memory formation and tumor protection. In our present work, we demonstrate that the combined administration of IMI-Sol and CD40 ligation unleashes fullblown specific T-cell responses in the priming and memory phase, strongly enhancing antitumor protection in mice. Interestingly, these effects were entirely CD4+ T cell independent, bypassing the necessity of helper T cells. Moreover, blockade of CD70 in vivo abrogated the boosting effect of CD40 ligation, indicating that the adjuvant effect of CD40 in TCI is mediated via CD70 on professional APCs. Furthermore, this work highlights the so far underappreciated importance of the CD70/CD27 interaction as a promising adjuvant target in TCI. Summing up, we demonstrate that the novel formulation IMI-Sol represents a powerful vaccination platform when applied in combination with sufficient adjuvant thereby overcoming current limitations of TCI.

Antifungal Drugs Influence Neutrophil Effector Functions.

There is a growing body of evidence for immunomodulatory side effects of antifungal agents on different immune cells, e.g., T cells. Therefore, the aim of our study was to clarify these interactions with regard to the effector functions of polymorphonuclear neutrophils (PMN). Human PMN were preincubated with fluconazole (FLC), voriconazole (VRC), posaconazole (POS), isavuconazole (ISA), caspofungin (CAS), micafungin (MFG), conventional amphotericin B (AMB), and liposomal amphotericin B (LAMB). PMN then were analyzed by flow cytometry for activation, degranulation, and phagocytosis and by dichlorofluorescein assay to detect reactive oxygen species (ROS). Additionally, interleukin-8 (IL-8) release was measured by enzyme-linked immunosorbent assay. POS led to enhanced activation, degranulation, and generation of ROS, whereas IL-8 release was reduced. In contrast, ISA-pretreated PMN showed decreased activation signaling, impaired degranulation, and lower generation of ROS. MFG caused enhanced expression of activation markers but impaired degranulation, phagocytosis, generation of ROS, and IL-8 release. CAS showed increased phagocytosis, whereas degranulation and generation of ROS were reduced. AMB led to activation of almost all effector functions besides impaired phagocytosis, whereas LAMB did not alter any effector functions. Independent from class, antifungal agents show variable influence on neutrophil effector functions in vitro Whether this is clinically relevant needs to be clarified.

Interferon-regulatory factor 4 is essential for the developmental program of T helper 9 cells.

Interferon-regulatory factor 4 (IRF4) is essential for the development of T helper 2 (Th2) and Th17 cells. Herein, we report that IRF4 is also crucial for the development and function of an interleukin-9 (IL-9)-producing CD4(+) T cell subset designated Th9. IRF4-deficient CD4(+) T cells failed to develop into IL-9-producing Th9 cells, and IRF4-specific siRNA inhibited IL-9 production in wild-type CD4(+) T cells. Chromatin-immunoprecipitation (ChIP) analyses revealed direct IRF4 binding to the Il9 promoter in Th9 cells. In a Th9-dependent asthma model, neutralization of IL-9 substantially ameliorated asthma symptoms. The relevance of these findings is emphasized by the fact that the induction of IL-9 production also occurs in human CD4(+) T cells accompanied by the upregulation of IRF4. Our data clearly demonstrate the central function of IRF4 in the development of Th9 cells and underline the contribution of this T helper cell subset to the pathogenesis of asthma.

Protein kinase CK2 governs the molecular decision between encephalitogenic TH17 cell and Treg cell development.

T helper 17 (TH17) cells represent a discrete TH cell subset instrumental in the immune response to extracellular bacteria and fungi. However, TH17 cells are considered to be detrimentally involved in autoimmune diseases like multiple sclerosis (MS). In contrast to TH17 cells, regulatory T (Treg) cells were shown to be pivotal in the maintenance of peripheral tolerance. Thus, the balance between Treg cells and TH17 cells determines the severity of a TH17 cell-driven disease and therefore is a promising target for treating autoimmune diseases. However, the molecular mechanisms controlling this balance are still unclear. Here, we report that pharmacological inhibition as well as genetic ablation of the protein kinase CK2 (CK2) ameliorates experimental autoimmune encephalomyelitis (EAE) severity and relapse incidence. Furthermore, CK2 inhibition or genetic ablation prevents TH17 cell development and promotes the generation of Treg cells. Molecularly, inhibition of CK2 leads to reduced STAT3 phosphorylation and strongly attenuated expression of the IL-23 receptor, IL-17, and GM-CSF. Thus, these results identify CK2 as a nodal point in TH17 cell development and suggest this kinase as a potential therapeutic target to treat TH17 cell-driven autoimmune responses.

Protein corona-mediated targeting of nanocarriers to B cells allows redirection of allergic immune responses.

BACKGROUND: Nanoparticle (NP)-based vaccines are attractive immunotherapy tools because of their capability to codeliver antigen and adjuvant to antigen-presenting cells. Their cellular distribution and serum protein interaction ("protein corona") after systemic administration and their effect on the functional properties of NPs is poorly understood. OBJECTIVES: We analyzed the relevance of the protein corona on cell type-selective uptake of dextran-coated NPs and determined the outcome of vaccination with NPs that codeliver antigen and adjuvant in disease models of allergy. METHODS: The role of protein corona constituents for cellular binding/uptake of dextran-coated ferrous nanoparticles (DEX-NPs) was analyzed both in vitro and in vivo. DEX-NPs conjugated with the model antigen ovalbumin (OVA) and immunostimulatory CpG-rich oligodeoxynucleotides were administered to monitor the induction of cellular and humoral immune responses. Therapeutic effects of this DEX-NP vaccine in mouse models of OVA-induced anaphylaxis and allergic asthma were assessed. RESULTS: DEX-NPs triggered lectin-induced complement activation, yielding deposition of activated complement factor 3 on the DEX-NP surface. In the spleen DEX-NPs targeted predominantly B cells through complement receptors 1 and 2. The DEX-NP vaccine elicited much stronger OVA-specific IgG2a production than coadministered soluble OVA plus CpG oligodeoxynucleotides. B-cell binding of the DEX-NP vaccine was critical for IgG2a production. Treatment of OVA-sensitized mice with the DEX-NP vaccine prevented induction of anaphylactic shock and allergic asthma accompanied by IgE inhibition. CONCLUSIONS: Opsonization of lectin-coated NPs by activated complement components results in selective B-cell targeting. The intrinsic B-cell targeting property of lectin-coated NPs can be exploited for treatment of allergic immune responses.

Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells.

BACKGROUND & AIMS: Wheat amylase-trypsin inhibitors (ATIs) are nutritional activators of innate immunity, via activation of the toll-like receptor 4 (TLR4) on myeloid cells. We aimed to characterize the biologic activity of ATIs in various foods and their effect on intestinal inflammation. METHODS: We selected 38 different gluten-containing and gluten-free products, either unprocessed (such as wheat, rye, barley, quinoa, amaranth, soya, lentils, and rice) or processed (such as pizza, pasta, bread, and biscuits). ATIs were extracted and their biological activities determined in TLR4-responsive mouse and human cell lines. Effects of oral ATIs on intestinal inflammation were determined in healthy C57BL/6 mice on a gluten-free or ATI-free diet and in mice given low-level polyinosinic:polycytidylic acid or dextran sodium sulfate to induce colitis. Parameters of innate and adaptive immune activation were determined in duodenum, ileum, colon, and mesenteric lymph nodes. RESULTS: Modern gluten-containing staples had levels of TLR4-activating ATIs that were as much as 100-fold higher than in most gluten-free foods. Processed or baked foods retained ATI bioactivity. Most older wheat variants (such as Emmer or Einkorn) had lower bioactivity than modern (hexaploid) wheat. ATI species CM3 and 0.19 were the most prevalent activators of TLR4 in modern wheat and were highly resistant to intestinal proteolysis. Their ingestion induced modest intestinal myeloid cell infiltration and activation, and release of inflammatory mediators-mostly in the colon, then in the ileum, and then in the duodenum. Dendritic cells became prominently activated in mesenteric lymph nodes. Concentrations of ATIs found in a normal daily gluten-containing diet increased low-level intestinal inflammation. CONCLUSIONS: Gluten-containing cereals have by far the highest concentrations of ATIs that activate TLR4. Orally ingested ATIs are largely resistant to proteases and heat, and increase intestinal inflammation by activating gut and mesenteric lymph node myeloid cells.

Drift time-specific collision energies enable deep-coverage data-independent acquisition proteomics.

We present a data-independent acquisition mass spectrometry method, ultradefinition (UD) MS(E). This approach utilizes ion mobility drift time-specific collision-energy profiles to enhance precursor fragmentation efficiency over current MS(E) and high-definition (HD) MS(E) data-independent acquisition techniques. UDMS(E) provided high reproducibility and substantially improved proteome coverage of the HeLa cell proteome compared to previous implementations of MS(E), and it also outperformed a state-of-the-art data-dependent acquisition workflow. Additionally, we report a software tool, ISOQuant, for processing label-free quantitative UDMS(E) data.

Regulatory T cell-derived adenosine induces dendritic cell migration through the Epac-Rap1 pathway.

Dendritic cells (DC) are one target for immune suppression by regulatory T cells (Treg), because their interaction results in reduced T cell stimulatory capacity and secretion of inhibitory cytokines in DC. We show that DC in the presence of Treg are more mobile as compared with cocultures with conventional CD4(+) T cells and form DC-Treg aggregates within 2 h of culture. The migration of DC was specifically directed toward Treg, as Treg, but not CD4(+) T cells, attracted DC in Boyden chambers. Treg deficient for the ectonucleotidase CD39 were unable to attract DC. Likewise, addition of antagonists for A2A adenosine receptors abolished the formation of DC-Treg clusters, indicating a role for adenosine in guiding DC-Treg interactions. Analysis of the signal transduction events in DC after contact to Treg revealed increased levels of cAMP, followed by activation of Epac1 and the GTPase Rap1. Subsequently activated Rap1 localized to the subcortical actin cytoskeleton in DC, providing a means by which directed locomotion of DC toward Treg is facilitated. In aggregate, these data show that Treg degrade ATP to adenosine via CD39, attracting DC by activating Epac1-Rap1-dependent pathways. As a consequence, DC-Treg clusters are formed and DC are rendered less stimulatory. This adenosine-mediated attraction of DC may therefore act as one mechanism by which Treg regulate the induction of immune responses by DC.

IL-10 and regulatory T cells cooperate in allergen-specific immunotherapy to ameliorate allergic asthma.

Human studies demonstrated that allergen-specific immunotherapy (IT) represents an effective treatment for allergic diseases. IT involves repeated administration of the sensitizing allergen, indicating a crucial contribution of T cells to its medicinal benefit. However, the underlying mechanisms of IT, especially in a chronic disease, are far from being definitive. In the current study, we sought to elucidate the suppressive mechanisms of IT in a mouse model of chronic allergic asthma. OVA-sensitized mice were challenged with OVA or PBS for 4 wk. After development of chronic airway inflammation, mice received OVA-specific IT or placebo alternately to airway challenge for 3 wk. To analyze the T cell-mediated mechanisms underlying IT in vivo, we elaborated the role of T-bet-expressing Th1 cells, T cell-derived IL-10, and Ag-specific thymic as well as peripherally induced Foxp3(+) regulatory T (Treg) cells. IT ameliorated airway hyperresponsiveness and airway inflammation in a chronic asthma model. Of note, IT even resulted in a regression of structural changes in the airways following chronic inhaled allergen exposure. Concomitantly, IT induced Th1 cells, Foxp3(+), and IL-10-producing Treg cells. Detailed analyses revealed that thymic Treg cells crucially contribute to the effectiveness of IT by promoting IL-10 production in Foxp3-negative T cells. Together with the peripherally induced Ag-specific Foxp3(+) Treg cells, thymic Foxp3(+) Treg cells orchestrate the curative mechanisms of IT. Taken together, we demonstrate that IT is effective in a chronic allergic disease and dependent on IL-10 and thymic as well as peripherally induced Ag-specific Treg cells.

Tick Salivary Sialostatin L Represses the Initiation of Immune Responses by Targeting IRF4-Dependent Transcription in Murine Mast Cells.

Coevolution of ticks and the vertebrate immune system has led to the development of immunosuppressive molecules that prevent immediate response of skin-resident immune cells to quickly fend off the parasite. In this article, we demonstrate that the tick-derived immunosuppressor sialostatin L restrains IL-9 production by mast cells, whereas degranulation and IL-6 expression are both unaffected. In addition, the expression of IL-1ß and IRF4 is strongly reduced in the presence of sialostatin L. Correspondingly, IRF4- or IL-1R-deficient mast cells exhibit a strong impairment in IL-9 production, demonstrating the importance of IRF4 and IL-1 in the regulation of the Il9 locus in mast cells. Furthermore, IRF4 binds to the promoters of Il1b and Il9, suggesting that sialostatin L suppresses mast cell-derived IL-9 preferentially by inhibiting IRF4. In an experimental asthma model, mast cell-specific deficiency in IRF4 or administration of sialostatin L results in a strong reduction in asthma symptoms, demonstrating the immunosuppressive potency of tick-derived molecules.

Protective dendritic cell responses against listeriosis induced by the short form of the deubiquitinating enzyme CYLD are inhibited by full-length CYLD.

The deubiquitinating enzyme CYLD is an important tumor suppressor and inhibitor of immune responses. In contrast to full-length CYLD, the immunological function of the naturally occurring short splice variant of CYLD (sCYLD) is insufficiently described. Previously, we showed that DCs, which lack full-length CYLD but express sCYLD, exhibit augmented NF-κB and DC activation. To explore the function of sCYLD in infection, we investigated whether DC-specific sCYLD regulates the pathogenesis of listeriosis. Upon Listeria monocytogenes infection of CD11c-Cre Cyld(ex7/8 fl/fl) mice, infection of CD8α(+) DCs, which are crucial for the establishment of listeriosis in the spleen, was not affected. However, NF-κB activity of CD11c-Cre Cyld(ex7/8 fl/fl) DCs was increased, while activation of ERK and p38 was normal. In addition, CD11c-Cre Cyld(ex7/8 fl/fl) DCs produced more TNF, IL-10, and IL-12 upon infection, which led to enhanced stimulation of IFN-γ-producing NK cells. In addition CD11c-Cre Cyld(ex7/8 fl/fl) DCs presented Listeria Ag more efficiently to CD8(+) T cells resulting in a stronger pathogen-specific CD8(+) T-cell proliferation and more IFN-γ production. Collectively, the improved innate and adaptive immunity and survival during listeriosis identify the DC-specific FL-CYLD/sCYLD balance as a potential target to modulate NK-cell and Ag-specific CD8(+) T-cell responses.