SEARCH · bioRxiv Science

Results for “immunology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources

bioRxiv2024

Diversity and functional specialization of oyster immune cells uncovered by integrative single cell level investigations

Mollusks are a major component of animal biodiversity and play a critical role in ecosystems and global food security. The Pacific oyster, Crassostrea (Magallana) gigas, is the most farmed bivalve mollusk in the world and is becoming a model species for invertebrate biology. Despite the extensive research on hemocytes, the immune cells of bivalves, their characterization remains elusive. Here we were able to extensively characterize the diverse hemocytes and identified at least seven functionally distinct cell types and three hematopoietic lineages. A combination of single-cell RNA sequencing, quantitative cytology, cell sorting, functional assays and pseudo-time analyses was used to deliver a comprehensive view of the distinct hemocyte types. This integrative analysis enabled us to reconcile molecular and cellular data and identify distinct cell types performing specialized immune functions, such as phagocytosis, reactive oxygen species production, copper accumulation, and expression of antimicrobial peptides. This study emphasized the need for more in depth studies of cellular immunity in mollusks and non-model invertebrates and set the ground for further comparative immunology studies at the cellular level.

immunology↗

bioRxiv2024

Dengue virus structural proteins are expressed on the surface of DENV-infected cells and are a target for antibody-dependent cellular phagocytosis

Dengue virus (DENV) is an arboviral pathogen found in over 100 countries and a source of significant morbidity and mortality. While the mechanisms underpinning the pathophysiology of severe dengue are incompletely understood, it has been previously suggested that antibodies directed against the DENV envelope (E) protein can facilitate antibody dependent enhancement (ADE) of the infection, increasing the number of infected cells and the severity of infection in an exposed individual. Accordingly, there is interest in defining mechanisms for directly targeting DENV-infected cells for immunologic clearance, an approach that bypasses the risk of ADE. We have previously demonstrated that antibodies specific for DENV non-structural protein 1 (NS1) can opsonize and facilitate the phagocytic clearance of DENV infected cells. However, it is currently unclear if other DENV antigens are expressed on the surface of infected cells, and if these antigens can be targeted by antibody-dependent clearance mechanisms. In this study, we demonstrate that DENV structural proteins are expressed on the surface of DENV-infected cells, and that these antigens can be opsonized by both DENV-immune sera and monoclonal antibodies. In addition, DENV E-specific antibodies can facilitate phagocytic uptake of DENV-infected cells, resulting in the target-cell membrane localizing to endosomes of the engulfing phagocyte. Notably, no DENV genetic material was observed localizing to the engulfing phagocyte, suggesting that horizontal transfer of DENV from the infecting cell is an unlikely occurrence. In their totality, these data reinforce the concept that DENV E-reactive antibodies have a multifaceted role in DENV immunity and pathogenesis beyond neutralization and/or infection-enhancement.

immunology↗

bioRxiv2024

Dietary iron deficiency impairs effector function of memory T cells following influenza infection

The establishment of memory T cell responses is critical to protection against pathogens and is influenced by the conditions under which memory formation occurs. Iron is an essential micronutrient for multiple immunologic processes and nutritional deficiency is a common problem worldwide. Despite its prevalence, the impact of nutritional iron deficiency on the establishment of memory T cell responses is not fully understood. In this study we investigate the impact of nutritional iron deficiency on the generation, phenotype, and function of memory T cell responses using a murine model of dietary iron modulation in the context of influenza infection. Iron deficient mice have decreased systemic iron levels and develop significant anemia. Increased T cell expression of the transferrin receptor (CD71) is seen in iron deficient mice at baseline. During primary influenza infection, iron deficient mice experience increased weight loss and phenotypic evidence of impairments in T cell activation. Following recovery from infection, iron deficient mice generate increased influenza specific memory T cells which exhibit impaired ability to produce IFN{gamma}, most notably within the lung. Importantly, the ability to produce IFN{gamma} and TNF is not recovered by co-culture with iron replete dendritic cells, suggesting a T cell intrinsic alteration in functional memory formation. Altogether, these results isolate a critical effect of nutritional iron deficiency on T cell memory development and function.

immunology↗

bioRxiv2024

CD6 Regulates CD4 T Follicular Helper Cell Differentiation and Humoral Immunity During Murine Coronavirus Infection

During activation the T cell transmembrane receptor CD6 becomes incorporated into the T cell immunological synapse where it can exert both co-stimulatory and co-inhibitory functions. Given the ability of CD6 to carry out opposing functions, this study sought to determine how CD6 regulates early T cell activation in response to viral infection. Infection of CD6 deficient mice with a neurotropic murine coronavirus resulted in greater activation and expansion of CD4 T cells in the draining lymph nodes. Further analysis demonstrated that there was also preferential differentiation of CD4 T cells into T follicular helper cells, resulting in accelerated germinal center responses and emergence of high affinity virus specific antibodies. Given that CD6 conversely supports CD4 T cell activation in many autoimmune models, we probed potential mechanisms of CD6 mediated suppression of CD4 T cell activation during viral infection. Analysis of CD6 binding proteins revealed that infection induced upregulation of Ubash3a, a negative regulator of T cell receptor signaling, was hindered in CD6 deficient lymph nodes. Consistent with greater T cell activation and reduced UBASH3a activity, the T cell receptor signal strength was intensified in CD6 deficient CD4 T cells. These results reveal a novel immunoregulatory role for CD6 in limiting CD4 T cell activation and deterring CD4 T follicular helper cell differentiation, thereby attenuating antiviral humoral immunity. ImportanceCD6 monoclonal blocking antibodies are being therapeutically administered to inhibit T cell activation in autoimmune disorders. However, the multifaceted nature of CD6 allows for multiple and even opposing functions under different circumstances of T cell activation. We therefore sought to characterize how CD6 regulates T cell activation in the context viral infections using an in vivo murine coronavirus model. In contrast to its role in autoimmunity, but consistent with its function in the presence of superantigens, we found that CD6 deficiency enhances CD4 T cell activation and CD4 T cell help to germinal center dependent antiviral humoral responses. Finally, we provide evidence that CD6 regulates transcription of its intracellular binding partner UBASH3a, which suppresses T cell receptor signaling and consequently T cell activation. These findings highlight the context dependent flexibility of CD6 in regulating in vivo adaptive immune responses, which may be targeted to enhance anti-viral immunity.

immunology↗

bioRxiv2024

Neutralization activity in chronic HIV infection is characterized by a distinct programming of follicular helper CD4 T cells

A subset of people living with HIV (PLWH) can produce broadly neutralizing antibodies (bNAbs) against HIV, but the lymph node (LN) dynamics that promote the generation of these antibodies are poorly understood. Here, we explored LN-associated histological, immunological, and virological mechanisms of bNAb generation in a cohort of anti-retroviral therapy (ART)-naive PLWH. We found that participants who produce bNAbs, termed neutralizers, have a superior LN-associated B cell follicle architecture compared with PLWH who do not. The latter was associated with a significantly higher in situ prevalence of Bcl-6hi follicular helper CD4 T cells (TFH), expressing a molecular program that favors their differentiation and stemness, and significantly reduced IL-10 follicular suppressor CD4 T cells. Furthermore, our data reveal possible molecular targets mediating TFH-B cell interactions in neutralizers. Together, we identify cellular and molecular mechanisms that contribute to the development of bNAbs in PLWH.

immunology↗

bioRxiv2024

Targeting mechanistic target of rapamycin complex 2 attenuates immunopathology in Systemic Lupus Erythematosus

ObjectiveWe aim to explore the role of mechanistic target of rapamycin complex (mTORC) 2 in systemic lupus erythematosus (SLE) development, the in vivo regulation of mTORC2 by type I interferon (IFN) signaling in autoimmunity, and to use mTORC2 targeting therapy to ameliorate lupus-like symptoms in an in vivo lupus mouse model and an in vitro coculture model using human PBMCs. MethodWe first induced lupus-like disease in T cell specific Rictor, a key component of mTORC2, deficient mice by topical application of imiquimod (IMQ) and monitored disease development. Next, we investigated the changes of mTORC2 signaling and immunological phenotypes in type I IFNAR deficient Lpr mice. We then tested the beneficial effects of anti-Rictor antisense oligonucleotide (Rictor-ASO) in a mouse model of lupus: MRL/lpr mice. Finally, we examined the beneficial effects of RICTOR-ASO on SLE patients PBMCs using an in vitro T-B cell coculture assay. ResultsT cell specific Rictor deficient mice have reduced age-associated B cells, plasma cells and germinal center B cells, and less autoantibody production than WT mice following IMQ treatment. IFNAR1 deficient Lpr mice have reduced mTORC2 activity in CD4+ T cells accompanied by restored CD4+ T cell glucose metabolism, partially recovered T cell trafficking, and reduced systemic inflammation. In vivo Rictor-ASO treatment improves renal function and pathology in MRL/lpr mice, along with improved immunopathology. In human SLE (N = 5) PBMCs derived T-B coculture assay, RICTOR-ASO significantly reduce immunoglobulin and autoantibodies production (P < 0.05). ConclusionTargeting mTORC2 could be a promising therapeutic for SLE.

immunology↗

bioRxiv2024

TBK1 and IKKϵ protect target cells from IFNγ-mediated T cell killing via an inflammatory apoptotic mechanism

Cytotoxic T cells produce interferon gamma (IFN{gamma}), which plays a critical role in anti-microbial and anti-tumor responses. However, it is not clear whether T cell-derived IFN{gamma} directly kills infected and tumor target cells, and how this may be regulated. Here, we report that target cell expression of the kinases TBK1 and IKK{varepsilon} regulate IFN{gamma} cytotoxicity by suppressing the ability of T cell-derived IFN{gamma} to kill target cells. In tumor targets lacking TBK1 and IKK{varepsilon}, IFN{gamma} induces expression of TNFR1 and the Z-nucleic acid sensor, ZBP1, to trigger RIPK1-dependent apoptosis, largely in a target cell-autonomous manner. Unexpectedly, IFN{gamma}, which is not known to signal to NF{kappa}B, induces hyperactivation of NF{kappa}B in TBK1 and IKK{varepsilon} double-deficient cells. TBK1 and IKK{varepsilon} suppress IKK/{beta} activity and in their absence, IFN{gamma} induces elevated NF{kappa}B-dependent expression of inflammatory chemokines and cytokines. Apoptosis is thought to be non-inflammatory, but our observations demonstrate that IFN{gamma} can induce an inflammatory form of apoptosis, and this is suppressed by TBK1 and IKK{varepsilon}. The two kinases provide a critical connection between innate and adaptive immunological responses by regulating three key responses: (1) phosphorylation of IRF3/7 to induce type I IFN; (2) inhibition of RIPK1-dependent death; and (3) inhibition of NF{kappa}B-dependent inflammation. We propose that these kinases evolved these functions such that their inhibition by pathogens attempting to block type I IFN expression would enable IFN{gamma} to trigger apoptosis accompanied by an alternative inflammatory response. Our findings show that loss of TBK1 and IKK{varepsilon} in target cells sensitizes them to inflammatory apoptosis induced by T cell-derived IFN{gamma}. Short SummaryIn the absence of TBK1 and IKK{varepsilon}, target cells are killed by T cells in an IFN{gamma}-dependent manner. In TBK1 and IKK{varepsilon}-deficient cells, IFN{gamma} induces RIPK1-dependent death, as well as hyper-induction of NF{kappa}B-dependent inflammatory genes. This suggests that any inhibition of TBK1/IKK{varepsilon} to block type I IFN expression will result in the demise of the cell accompanied by an alternate inflammatory program. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/606693v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1606b75org.highwire.dtl.DTLVardef@12eebc0org.highwire.dtl.DTLVardef@177c033org.highwire.dtl.DTLVardef@eb5819_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

Quantifying conformational changes in the TCR:pMHC-I binding interface

T cells form one of the key pillars of adaptive immunity. Using their surface bound T cell antigen receptors (TCRs), these cells screen millions of antigens presented by major histocompatability complex (MHC) or MHC-like molecules. In other protein families, the dynamics of protein-protein interactions have important implications for protein function. Case studies of TCR:class I peptide-MHCs (pMHC-Is) structures have reported mixed results on whether the binding interfaces undergo conformational change during engagement and no robust statistical quantification has been done to generalise these results. It thus remains an open question if movement occurs in the binding interface that enables recognition and activation of T cells. In this work, we quantify the conformational changes in the TCR:pMHC-I binding interface by creating a dataset of 358 structures, comprising 25 TCRs, 20 MHC alleles, and 58 peptide structures in both unbound (apo) and bound (holo) conformations. In support of some case studies, we demonstrate that all complimentary determining region (CDR) loops move to a certain extent but only CDR3 and CDR3{beta} loops modify their shape when binding pMHC-Is. We also map out the contacts between TCRs and pMHC-Is, generating a novel fingerprint of TCRs on MHC molecules and show that the CDR3 tends to bind the N-terminus of the peptide and the CDR3{beta} tends to bind the C-terminus of the peptide. Finally, we show that the presented peptides can undergo conformational changes when engaged by TCRs, as has been reported in past literature, but novelly show these changes depend on how the peptides are anchored in the MHC binding groove. Our work has implications in understanding the behaviour of TCR:pMHC-I interactions and providing insights that can be used for modelling T cell antigen specificity, an ongoing grand challenge in immunology.

immunology↗

bioRxiv2024

The Changing Immune Landscape of Innate-like T Cells and Innate Cells Throughout Life

Spectral flow cytometry is an advanced immunological tool that enables comprehensive analysis of the immune system by simultaneously comparing innate and adaptive immune cells. Here, using a 40-colour antibody panel we advance our knowledge of innate and innate-like T cells by investigating chemokine receptors, activation and maturation markers not usually assessed on these populations and examine age-related effects to these immune cell subsets. We characterised phenotypic changes of peripheral blood mononuclear cells (PBMC) in three age groups: newborn (cord blood), adults aged 20-30 years, and adults aged 70-80 years, focusing on innate-like T cells and innate cells, including MAIT cells, NKT cells, {gamma}{delta} T cells, ILCs, and Natural Killer (NK) cells. We identify subsets of double-negative (DN) T cells (CD4- CD8-) and CD161+ T cells that increase in an age-related manner and exhibit a phenotype similar to innate-like T cells, MAIT cells and {gamma}{delta} T cells. Innate-like T cell subsets express similar patterns of the chemokine receptors and maturation markers CCR4, CCR6, CD27, CD38, CD57 and CD45RA, and resemble memory subsets of conventional CD4+ T cells and CD8+ T cells. We could detect ILCs in all age ranges, although the frequency of ILC1, ILC2, and ILC3 subsets decreased with age. Notably, we identify the NK maturation marker, CD57, as a universal marker that defines ageing populations of innate and adaptive immune cells. This study enhances our understanding of the ontogeny of human immune cells, highlighting significant age-related changes in the frequency and phenotype of immune cells.

immunology↗

bioRxiv2024

Malnutrition drives infection susceptibility and dysregulated myelopoiesis that persists after refeeding intervention

Undernutrition is one of the largest persistent global health crises, with nearly 1 billion people facing severe food insecurity. Infectious disease represents the main underlying cause of morbidity and mortality for malnourished individuals, with infection during malnutrition representing the leading cause of childhood mortality worldwide. In the face of this complex challenge, simple refeeding protocols have remained the primary treatment strategy. Although an association between undernutrition and infection susceptibility has been appreciated for over a century, the underlying mechanisms remain poorly understood and the extent to which refeeding intervention is sufficient to reverse nutritionally acquired immunodeficiency is unclear. Here we investigate how malnutrition leads to immune dysfunction and the ability of refeeding to repair it. We find that chronic malnutrition induced through prolonged dietary restriction (40% reduction in food intake) severely impairs the ability of mice to control a sub-lethal Listeria monocytogenes infection. Malnourished mice exhibit blunted immune cell expansion, impaired immune function, and accelerated contraction prior to pathogen clearance. While this defect is global, we find that myelopoiesis is uniquely impacted, resulting in reduced neutrophil and monocyte numbers prior to and post-infection. Upon refeeding, we observe that mice recover body mass, size, cellularity across all major immune organs, the capacity to undergo normal immune cell expansion in response to infection, and a restoration in T cell responses. Despite this broad improvement, refed mice remain susceptible to Listeria infection, uncoupling global lymphoid atrophy from immunodeficiency. We find peripheral neutrophil and monocyte numbers fail to fully recover and refed mice are unable to undergo normal emergency myelopoiesis. Altogether, this work identifies dysregulated myelopoiesis as a link between prior nutritional state and immunocompetency. We believe these findings raise the possibility that exposure to food scarcity should be treated as an immunologic variable, even post-recovery, with considerations for how patient medical history and public health policy.

immunology↗

bioRxiv2024

Ex vivo Model of Functioning Human Lymph Node Reveals Pivotal Role for Innate Lymphoid Cells and Stromal Populations in Response to Vaccine Adjuvant

Immunological processes that underpin the administration of therapeutics and vaccines are poorly defined due to a lack of models which faithfully recapitulate human immune responses. Inbred mice lack the diversity inherent to people, while the microanatomical organisation of human tissue is lost in isolated cell suspensions. We describe precision-cut human lymph node (LN) slices as architecturally-preserved, functioning lymphoid tissue model system, and explore early inflammatory responses to a potent vaccine liposomal adjuvant containing a TLR4-agonist and QS21 saponin. Combining scRNA-seq, multiplexed immunofluorescence and secretome analysis, we dissect direct and indirect signalling pathways in both leukocytes and stromal cells to reveal communication networks linking innate and adaptive immunity. Application of molecular inhibitors reveals that secretion of IL-1{beta}, but not IL-18, is TLR4-dependent in human LN. Retaining donor-to-donor immune variation, this ex vivo LN model system enables the study of pathways previously difficult to observe in humans, paving the way towards precision medicine.

immunology↗

bioRxiv2024

Early immune response to Coccidioides is characterized by robust neutrophil and fibrotic macrophage recruitment and differentiation

Coccidioidomycosis, or Valley fever, is an emerging respiratory disease caused by soil dwelling fungi of the Coccidioides genus that is expected to spread from the southwest into the central U.S. by 2050. While 60% of infections are asymptomatic, the other 40% of patients experience a range of symptoms, from self-limiting pneumonia to life-threatening disseminated disease. The immunological events that underlie the progression to severe disease remain under defined. Here, we probed the early immune response to Coccidioides using a high dose of an attenuated strain of C. posadasii in a mouse model of infection coupled with single-cell RNA sequencing. At 24 hours post-infection, robust immune infiltration is detected in the lung, marked by high levels of inflammatory PD-L1+ neutrophils and fungal-contact dependent pro-fibrotic Spp1+ macrophages. These findings elucidate the early dynamics of the host response to Coccidioides and provide a deeper understanding of host-pathogen interactions in the lung. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/609001v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@198a77forg.highwire.dtl.DTLVardef@11c9207org.highwire.dtl.DTLVardef@b71257org.highwire.dtl.DTLVardef@115447d_HPS_FORMAT_FIGEXP M_FIG C_FIG ImportanceBy examining early immune dynamics in the lungs, we uncover critical insights into how myeloid cells, particularly neutrophils and macrophages, are recruited and differentiated during Coccidioides infection. The discovery of specific immune cell subsets, such as PD-L1+ neutrophils and Spp1+ macrophages, which are associated with inflammation and fibrosis, highlights potential targets for therapeutic intervention. These findings provide a deeper understanding of the host-pathogen interactions that occur during Coccidioides infection, offering valuable directions for developing more effective treatments and preventive strategies against this increasingly prevalent disease.

immunology↗

bioRxiv2024

Assembly and performance of a cholera RDT prototype that detects both Vibrio cholerae and associated bacteriophage as a proxy for pathogen detection

IntroductionCholera rapid diagnostic tests (RDTs) are vulnerable to virulent bacteriophage predation. We hypothesized that an enhanced cholera RDT that detects the common virulent bacteriophage ICP1 might serve as a proxy for pathogen detection. We previously developed a monoclonal antibody (mAb) to the ICP1 major capsid protein. Our objective herein was to design and assemble a first-of-its-kind RDT that detects both a bacterial pathogen (Vibrio cholerae) and associated virulent bacteriophage (ICP1). MethodCandidate mAbs were expanded to increase design options and evaluated by immunological assays (ELISA; western blot). A subset of mAbs were selected for gold conjugation and printing on the RDT. The limit of detection (LOD) of prototype RDTs were determined in diarrheal stools with the addition of ICP1. ResultsThree mAb candidates were developed and evaluated for the capsid decoration protein (ORF123) and tail fiber protein (ORF93), and the prior mAb for the major capsid protein (ORF122). A single mAb sandwich RDT prototype for ORF122 was able to detect ICP1; RDTs with mAbs to ORF123 and ORF93 failed to detect ICP1 in single or dual sandwich configurations. Biologically meaningful LODs for ICP1 were achieved only after boiling the stool with ICP1; analysis by electron microscopy suggested increased epitope availability after boiling. ConclusionIn this study, we demonstrate a proof of concept for a functional RDT that can detect both the primary pathogen and a common virulent bacteriophage as a proxy for pathogen detection. Further optimization is required before scaled production and implementation.

immunology↗

bioRxiv2024

Therapeutic DNA Vaccine Targeting Mycobacterium tuberculosis Persisters Shortens Curative Tuberculosis Treatment

Mycobacterium tuberculosis (Mtb) is one of the leading infectious causes of death worldwide. There is no available licensed therapeutic vaccine that shortens active tuberculosis (TB) disease drug treatment and prevents relapse, despite the World Health Organizations calls. Here, we show that an intranasal DNA vaccine containing a fusion of the stringent response relMtb gene with the gene encoding the immature dendritic cell-targeting chemokine, MIP-3/CCL20, shortens the duration of curative TB treatment in immunocompetent mice. Compared to the first-line regimen for drug-susceptible TB alone, our novel adjunctive vaccine induced greater RelMtb-specific T-cell responses associated with optimal TB control in spleen, blood, lungs, mediastinal lymph nodes, and bronchoalveolar lavage (BAL) fluid. These responses were sustained, if not augmented, over time. It also triggered more effective dendritic cell recruitment, activation, and colocalization with T cells, implying enhanced crosstalk between innate and adaptive immunity. Moreover, it potentiated a 6-month TB drug-resistant regimen, rendering it effective across treatment regimens, and also showed promising results in CD4+ knockout mice, perhaps due to enhanced Rel-specific CD8+ T-cell responses. Notably, our novel fusion vaccine was also immunogenic in nonhuman primates, the gold standard animal model for TB vaccine studies, eliciting antigen-specific T-cell responses in blood and BAL fluid analogous to those observed in protected mice. Our findings have critical implications for therapeutic TB vaccine clinical development in immunocompetent and immunocompromised populations and may serve as a model for defining immunological correlates of therapeutic vaccine-induced protection. One sentence summaryA TB vaccine shortens curative drug treatment in mice by eliciting strong TB-protective immune responses and induces similar responses in macaques.

immunology↗

bioRxiv2024

Prolonged thermal stress enhances mosquito tolerance to viral infection

How and to what extent mosquito-virus interaction is influenced by climate change is a complex question of ecological and epidemiological relevance. We worked at the intersection between thermal biology and vector immunology and studied shifts in tolerance and resistance to the cell fusing agent virus (CFAV), a prominent component of the mosquito virome know to contribute to shaping mosquito vector competence, in warm-acclimated and warm-evolved Aedes albopictus mosquitoes. We show that the length of the thermal challenge influences the outcome of the infection with warm-evolved mosquitoes being more tolerant to CFAV infection, while warm-acclimated mosquitoes being more resistant and suffering from extensive fitness costs. These results highlight the importance of considering fluctuations in vector immunity in relation to the length of a thermal challenge to understand natural variation in vector response to viruses and frame realistic transmission models.

immunology↗

bioRxiv2024

Adjuvant-dependent impacts on vaccine-induced humoral responses and protection in preclinical models of nasal and genital colonization by pathogenic Neisseria

Neisseria gonorrhoeae, which causes the sexually transmitted infection gonorrhea and N. meningitidis, a leading cause of bacterial meningitis and septicemia, are closely related human-restricted pathogens that inhabit distinct primary mucosal niches. While successful vaccines against invasive meningococcal disease have been available for decades, the rapid rise in antibiotic resistance has led to an urgent need to develop an effective gonococcal vaccine. Several surface antigens are shared among these two pathogens, making cross-species protection an exciting prospect. However, the type of vaccine-mediated immune response required to achieve protection against respiratory versus genital infection remains ill defined. In this study, we utilize well established mouse models of female lower genital tract colonization by N. gonorrhoeae and upper respiratory tract colonization by N. meningitidis to examine the performance of transferrin binding protein B (TbpB) vaccines formulated with immunologically distinct vaccine adjuvants. We demonstrate that vaccine-mediated protection is influenced by the choice of adjuvant, with Th1/2-balanced adjuvants performing optimally against N. gonorrhoeae, and both Th1/2-balanced and Th2-skewing adjuvants leading to a significant reduction in N. meningitidis burden. We further establish a lack of correlation between protection status and the humoral response or bactericidal titre. Combined, this work provides supports the feasibility for a single vaccine formulation to achieve pan-neisserial coverage.

immunology↗

bioRxiv2024

β2-Adrenergic Biased Agonist Inhibits the Development of Th17 and the Response of Memory Th17 Cells in an NF-κB-Dependent Manner.

IntroductionAdrenergic receptors regulate metabolic, cardiovascular and immunological functions in response to the sympathetic nervous system. The effect of {beta}2-adrenergic receptor (AR) as a high-expression receptor on different subpopulations of T cells is complex and varies depending on the type of ligand and context. While traditional {beta}2-AR agonists generally suppress T cells, they potentially enhance IL-17A production by Th17 cells. The effects of pharmacological drugs that count as biased agonists of AR like nebivolol are not completely understood. We investigated the impact of nebivolol on human memory CD4+ T (Th1, Th2, Th17) cells and polarized naive Th17 cells highlighting its potential for IL-17A suppression via a non-canonical {beta}2AR cell-signaling pathway. MethodsThe effects of nebivolol were tested on healthy human peripheral blood mononuclear cells, purified memory Th cells, and polarized naive Th17 cells activated with antiCD3/antiCD28/antiCD2 ImmunoCult reagent. IFN-{gamma}, IL-4, and IL-17A which are primarily derived from Th1, Th2, and Th17 cells respectively, were quantified by ELISA and flow cytometry. IL-10 was measured by ELISA. Gene expression of RORC, ADRB1, ADRB2, and ADRB3 was evaluated by qPCR. The ADRB2 gene was knocked out in memory Th cells using CRISPR/Cas9. Protein expression of phosphorylated-serine133-CREB and phosphorylated-NF-{kappa}B p65 was assessed by Western blot. Proliferation was assessed by fluorescent dye loading and flow cytometry. ResultsNebivolol treatment decreased IL-17A and IFN-{gamma} secretion by activated-memory Th cells and elevated IL-4 levels. Nebivolol reduced the proportion of IL-17A+ Th cells and downregulated RORC expression. Unlike the {beta}2-AR agonist terbutaline, nebivolol inhibited the shift of naive CD4+ T cells towards the Th17 phenotype. IL-10 and proliferation index remained unchanged. Nebivolol-treated {beta}2-knockout memory Th cells showed significant inhibition of {beta}2AR-mediated signaling, evidenced by the absence of IL-17A suppression compared to controls. Phosphorylation of the NF-{kappa}B p65 subunit was inhibited by nebivolol, but CREB phosphorylation was not changed, suggesting a selective transcriptional control. ConclusionsThe findings demonstrate that nebivolol acts through a {beta}2-AR-mediated signaling pathway, as a distinctive anti-inflammatory agent capable of selectively shifting Th17 cells and suppressing phosphorylation of NF-{kappa}B. This highlights nebivolols potential for therapeutic interventions in chronic autoimmune conditions with elevated IL-17A levels.

immunology↗

bioRxiv2024

IL-34 empowers regulatory T cells with novel non-canonical function to safeguard brain barrier integrity during neuro-inflammation.

In efforts to find reparative strategies for brain damage, brain-associated regulatory T cells (Tregs) have gained increasing attention in recent years. Beyond their textbook immunoregulatory function, Tregs have emerged as key players in the response to brain trauma and the restoration of damaged brain tissue. Here, we are the first to describe a novel, non-canonical function of Tregs in maintaining the sealing capacity of both the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier. Moreover, we identified the cytokine IL-34 as a critical determinant in this newly unveiled Treg function. Mechanistically, IL-34 exerts its influence by modulating the expression and localization of the tight junction protein ZO-1 in both BBB endothelial cells and choroid plexus epithelial cells, thereby reinforcing the strength of the brain barriers. Given the well-established notion of leaky brain barriers and the involvement of immunological components in neurological diseases such as Alzheimers disease (AD) and multiple sclerosis (MS), we further demonstrate diminished IL-34 expression in Tregs derived from patients with relapsing-remitting MS (RR-MS) and patients with AD and even mild cognitive impairment (MCI). Remarkably, our study reveals the potential of IL-34 treatment in reinstating the integrity of brain barriers within murine models mimicking these neurological disorders. These ground-breaking findings shed light on the intricate relationship between Tregs, IL-34, and the integrity of brain barriers. They offer novel avenues for therapeutic approaches to ameliorate brain barrier dysfunction in the context of neurological disorders.

immunology↗