Search

The major histocompatibility complexes of vertebrates play a key role in the immune response. Antigen-presenting cells are loaded on MHC I molecules, which mainly present endogenous antigens; when MHC I presents exogenous antigens, this is called cross-presentation. The discovery of cross-presentation provides an important theoretical basis for the study of exogenous antigens. Cross-presentation is a complex process in which MHC I molecules present antigens to the cell surface to activate CD8+ T lymphocytes. The process of cross-representation includes many components, and this article briefly outlines the origins and development of MHC molecules, gene structures, functions, and their classical presentation pathways. The cross-presentation pathways of MHC I molecules, the cell lines that support cross-presentation, and the mechanisms of MHC I molecular transporting are all reviewed. After more than 40 years of research, the specific mechanism of cross-presentation is still unclear. In this paper, we summarize cross-presentation and anticipate the research and development prospects for cross-presentation. [ABSTRACT FROM AUTHOR]

Macrophages are the predominant component of innate immunity, which is an important protective barrier of our body. Macrophages are present in all organs and tissues of the body, their main functions include immune surveillance, bacterial killing, tissue remodeling and repair, and clearance of cell debris. In addition, macrophages can present antigens to T cells and facilitate inflammatory response by releasing cytokines. Macrophages are of high concern due to their crucial roles in multiple physiological processes. In recent years, new advances are emerging after great efforts have been made to explore the mechanisms of macrophage activation. Ion channel is a class of multimeric transmembrane protein that allows specific ions to go through cell membrane. The flow of ions through ion channel between inside and outside of cell membrane is required for maintaining cell morphology and intracellular signal transduction. Expressions of various ion channels in macrophages have been detected. The roles of ion channels in macrophage activation are gradually caught attention. K+ channels are the most studied channels in immune system. However, very few of published papers reviewed the studies of K+ channels on macrophages. Here, we will review the four types of K+ channels that are expressed in macrophages: voltage-gated K+ channel, calcium-activated K+ channel, inwardly rectifying K+ channel and two-pore domain K+ channel. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs), particularly exosomes (30–150 nm), are an emerging delivery system in mediating cellular communications, which have been observed for priming immune responses by presenting parent cell signaling proteins or tumor antigens to immune cells. Therefore, preparation of antigenic exosomes that can play therapeutic roles, particularly in cancer immunotherapy, is emerging. However, standard benchtop methods (e.g., ultracentrifugation and filtration) lack the ability to purify antigenic exosomes specifically among other microvesicle subtypes, due to the non-selective and time-consuming (＞10 h) isolation protocols. Exosome engineering approaches, such as the transfection of parent cells, also suffer from poor yields, low purity, and time-consuming operations. In this paper, we introduce a streamlined microfluidic cell culture platform for integration of harvesting, antigenic modification, and photo-release of surface engineered exosomes in one workflow, which enables the production of intact, MHC peptide surface engineered exosomes for cytolysis activation. A PDMS microfluidic cell culture chip is simply cast from a 3D-printed mold. This proof-of-concept study demonstrated the enhanced ability of harvested exosomes in antigen presentation and T cell activation, by decorating melanoma tumor peptides on the exosome surface (e.g., gp-100, MART-1, and MAGE-A3). Such surface engineered antigenic exosomes were harvested in real-time from the on-chip culture of leukocytes isolated from human blood, leading to much faster cellular uptake. The activation of gp100-specific CD8 T cells which were purified from the spleen of 2 Pmel1 transgenic mice was evaluated using surface engineered exosomes prepared from murine antigen presenting cells. Antigen-specific CD8 T cell proliferation was significantly induced by the engineered exosomes compared to that by native, non-engineered exosomes. This microfluidic platform serves as an automated and highly integrated cell culture device for rapid and real-time production of therapeutic exosomes that could advance cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Kissing molars (KM) or rosette formation is a term that is used to describe impacted teeth contacting occlusal surfaces in a single follicular space and their roots pointing in opposite directions. In some cases kissing molars can be seen but occurrence of bilateral kissing molars is extremely rare phenomenon in the dental literature and the aetiology of this phenomenon is still unknown. In this paper we describe a case and review of the literature and discuss the management of this pathology. In our case, extremely rare form of impacted bilateral kissing molars was extracted surgically. The decision of extraction of asymptomatic kissing molars represents surgical dilemma. There may be many surgical complications; on the other hand in some cases surgical intervention is unavoidable. Few treatment options were described in the literature. This phenomenon can be sign of various medical conditions that may require further investigation. In this paper, our treatment option is in agreement with the literature suggesting the surgical removal of both teeth at either side of the mandible. [ABSTRACT FROM AUTHOR]

Malignant tumour cells, including malignant keratinocytes of oral squamous cell carcinoma (OSCC), exist in conjunction with other functional cells and it is well recognised that interaction between these groups of cells is important in tumour progression. In addition to cells (tumour cells, immune/inflammatory cells, fibroblasts, vascular and lymphatic endothelial cells, adipocytes) the tumour microenvironment (TME) comprises extracellular matrix and soluble factors, signalling molecules and metabolites such as enzymes, growth factors, cytokines, microRNAs and microvesicles. Our Oral Molecular and Immunopathology Research Group has explored and examined the interactions of the immune network involved in the TME such as tumour infiltrating lymphocytes (TILs), regulatory T cells (Tregs), antigen presenting cells (APCs), associated cytokines such as IL17, IL22, IL23 and other current potential anti-cancer targets such as ER stress and exosomes. This paper will provide an overview of the history of OSCC research at the University of Otago, as well as elaborate current understanding of the TME in OSCC, based on ongoing research undertaken in the Oral Molecular and Immunopathology Research Group of the Sir John Walsh Research Institute at the Faculty of Dentistry, University of Otago. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by cartilage damage, bone tissue destruction, morphological changes in synovial fluids, and synovial joint inflammation. The inflamed synovial tissue has potential for passive and active targeting because of enhanced permeability and retention effect and the existence of RA synovial macrophages and fibroblasts that selectively express surface receptors such as folate receptor β, CD44 and integrin αVβ. Although there are numerous interventions in RA treatment, they are not safe and effective. Therefore, it is important to develop new drug or drug delivery systems that specifically targets inflamed/swollen joints but attenuates other possible damages to healthy tissues. Recently some receptors such as toll-like receptors (TLRs), the nucleotide-binding oligomerization domain-like receptors, and Fc-γ receptor have been identified in synovial tissue and immune cells that are involved in induction or suppression of arthritis. Analysis of the TLR pathway has moreover suggested new insights into the pathogenesis of RA. In the present paper, we have reviewed drug delivery strategies based on receptor targeting with novel ligand-anchored carriers exploiting CD44, folate and integrin αVβ as well as TLRs expressed on synovial monocytes and macrophages and antigen presenting cells, for possible active targeting in RA. TLRs could not only open a new horizon for developing new drugs but also their antagonists or humanized monoclonal antibodies that block TLRS specially TLR4 and TLR9 signaling could be used as targeting agents to antigen presenting cells and dendritic cells. As a conclusion, common conventional receptors and multifunctional ligands that arte involved in targeting receptors or developing nanocarriers with appropriate ligands for TLRs can provide profoundly targeting drug delivery systems for the effective treatment of RA. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are the most effective professional antigen-presenting cell. They ferry antigen from the extremities to T cells and are essential for the initiation of an adaptive immune response. Despite interest in how DCs respond to chemical stimuli, there have been few attempts to model DC migration. In this paper, we simulate the motility of DCs by modeling the generation of forces by filopodia and a force balance on the cell. The direction of fliopodial extension is coupled to differential occupancy of cognate chemokine receptors across the cell. Our model simulates chemokinesis and chemotaxis in a variety of chemical and mechanical environments. Simulated DCs undergoing chemokinesis were measured to have a speed of 5.1 ± 0.07 μm·min-1 and a persistence time of 3.2 ± 0.46 min, consistent with experiment. Cells undergoing chemotaxis exhibited a stronger chemotactic response when exposed to lower average chemokine concentrations, also consistent with experiment. We predicted that when placed in two opposing gradients, cells will cluster in a line, which we call the “line of equistimulation;” this clustering has also been observed. We calculated the effect of varying gradient steepness on the line of equistimulation, with steeper gradients resulting in tighter clustering. Moreover, gradients are found to be most potent when cells are in a gradient of chemokine whose mean concentration is close to the binding of the Kd to the receptor, and least potent when the mean concentration is 0.1Kd. Comparing our simulations to experiment, we can give a quantitative measure of the strength of certain chemokines relative to others. Assigning the signal of CCL19 binding CCR7 a baseline strength of 1, we found CCL21 binding CCR7 had a strength of 0.28, and CXCL12 binding CXCR4 had a strength of 0.30. These differences emerge despite both chemokines having virtually the same Kd, suggesting a mechanism of signal amplification in DCs requiring further study. [ABSTRACT FROM AUTHOR]

Errors in neuron-microglial interaction are known to lead to microglial phagocytosis of live neurons and excessive neuronal loss, potentially yielding poorer clinical outcomes. Factors that affect neuron-microglial interaction have the potential to influence the error rate. Clinical comorbidities that unfavorably impact neuron-microglial interaction may promote a higher rate of neuronal loss, to the detriment of patient outcome. This paper proposes that many common, clinically modifiable comorbidities have a common thread, in that they all influence neuron-microglial interactions. Comorbidities like traumatic brain injury, infection, stress, neuroinflammation, loss of neuronal metabolic integrity, poor growth factor status, and other factors, all have the potential to alter communication between neurons and microglia. When this occurs, microglial phagocytosis of live neurons can increase. In addition, microglia can shift into a morphological form in which they express major histocompatibility complex II (MHC-II), allowing them to function as antigen presenting cells that present neuronal debris as antigen to invading T cells. This can increase risk for the development of CNS autoimmunity, or can exacerbate existing CNS autoimmunity. The detrimental influence of these comorbidities has the potential to contribute to the mosaic of factors that determine patient outcome in some CNS pathologies that have neuropsychiatric involvement, including TBI and CNS disorders with autoimmune components, where excessive neuronal loss can yield poorer clinical outcomes. Recognition of the impact of these comorbidities may contribute to an understanding of the common clinical observation that many seemingly disparate factors contribute to the overall picture of case management and clinical outcome in these complex disorders. In a clinical setting, knowing how these comorbidities can influence neuron-microglial interaction can help focus surveillance and care on a broader group of potential therapeutic targets. Accordingly, an interest in the mechanisms underlying the influence of these factors on neuron-microglial interactions is appropriate. Neuron-microglial interaction is reviewed, and the various mechanisms by which these potential comorbidities influence neuro-microglial interaction are described. [ABSTRACT FROM AUTHOR]

Foot and mouth disease (FMD) is a highly contagious infection caused by FMDvirus (FMDV) that affects livestock worldwide with significant economic impact. The main strategy for the control is vaccination with FMDV chemically inactivated with binary ethylenimine (FMDVi). In FMDV infection and vaccination, B cell response plays a major role by providing neutralizing/protective antibodies in animal models and natural hosts. Extracellular vesicles (EVs) and small EVs (sEVs) such as exosomes are important in cellular communication. EVs secreted by antigen-presenting cells (APC) like dendritic cells (DCs) participate in the activation of B and T cells through the presentation of native antigen membrane-associated to B cells or by transferring MHC-peptide complexes to T cells and even complete antigens from DCs. In this study, we demonstrate for the first time that APC activated with the FMDVi O1 Campos vaccine-antigens secrete EVs expressing viral proteins/peptides that could stimulate FMDV-specific immune response. The secretion of EVs-FMDVi is a time-dependent process and can only be isolated within the first 24 h post-activation. These vesicles express classical EVs markers (CD9, CD81, and CD63), along with immunoregulatory molecules (MHC-II and CD86). With an average size of 155 nm, they belong to the category of EVs. Studies conducted in vitro have demonstrated that EVs-FMDVi express antigens that can stimulate a specific B cell response against FMDV, including both marginal zone B cells (MZB) and follicular B cells (FoB). These vesicles can also indirectly or directly affect T cells, indicating that they express both B and T epitopes. Additionally, lymphocyte expansion induced by EVs-FMDVi is greater in splenocytes that have previously encountered viral antigens in vivo. The present study sheds light on the role of EVs derived fromAPC in regulating the adaptive immunity against FMDV. This novel insight contributes to our current understanding of the immune mechanisms triggered by APC during the antiviral immune response. Furthermore, these findings may have practical implications for the development of new vaccine platforms, providing a rational basis for the design of more effective vaccines against FMDV and other viral diseases. [ABSTRACT FROM AUTHOR]

Recently the FDA conducted a risk investigation and labeled the Boxed Warning for all BCMA- and CD19-directed CAR-T cell therapy, so does it mean that the public must take risk of secondary cancer to receive cell therapy? Here, without lentivirus and professional antigen presenting cell application, a novel tumor-specific T-cell therapy was successfully developed only by co-culturing MHC+ cancer cells and Naïve-T cells under the CD28 co-stimulatory signals. These tumor-specific T-cells could be separated through cell size and abundantly produced from peripheral blood, and would spontaneously attack target cells that carrying the same tumor antigen while avoiding others in vitro test. Moreover, it markedly decreased 90% tumor nodules companying with greatly improving overall survival (76 days vs 30 days) after twice infusion back to mice. This work maximally avoided the risks of secondary cancer and non-specific killing, and might open a revolutionary beginning of natural tumor-specific T-cell therapy. Highlights: Tumor specific T-cell generation without lentivirus and professional APC application. Only by co-culturing MHC+ cancer cell and Naïve-T cell supplying CD28 signal. Easy separation by cell size and fast generation from peripheral blood. Maximally avoid troubles of viral safety and non-specific reaction. Novel model of T-cell activation could be used to bioprospect medicinal molecules instead of CD28 from abundant natural products. [ABSTRACT FROM AUTHOR]

Virus-like nanoparticles (VNP) are regarded as efficient vaccination platforms and have proven to be useful for the non-anaphylactogenic delivery of allergen-specific immunotherapy in preclinical models previously. Herein, we sought to determine the mode of VNP uptake by antigen presenting cells (APC). Accordingly, we screened a collection of substances known to inhibit different uptake pathways by APC. The human leukemia monocytic cell line THP-1 and the murine dendritic cell line DC 2.4 were examined for the uptake of fluorescently labelled VNP in the presence or absence of inhibitors. The inhibitory effect of candidate substances that blocked VNP uptake in APC lines was subsequently evaluated in studies with primary APC present in splenocyte and lung cell homogenates in vitro and upon intratracheal application of VNP in vivo. The uptake of allergen-specific VNP in vitro and in vivo was mainly observed by macrophages and CD103+ dendritic cells and was sensitive to inhibitors that block macropinocytosis, such as hyperosmolarity induced by sucrose or the polyphenol compound Rottlerin at low micromolar concentrations but not by other inhibitors. Also, T-cell proliferation induced by allergen-specific VNP was significantly reduced by both substances. In contrast, substances that stimulate macropinocytosis, such as Heparin and phorbol myristate acetate (PMA), increased VNP-uptake and may, thus, help modulate allergen-specific T-cell responses. We have identified macropinocytosis as the principal uptake mechanism of APC for allergen-specific VNP in vitro and in vivo, paving the way for further improvement of VNP-based therapies, especially those that can be used for tolerance induction in allergy, in the future. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) are major contributors to immunological responses following solid organ transplantation. Donor derived EVs are best known for their role in transplant rejection through transferring donor major histocompatibility complex proteins to recipient antigen presenting cells, a phenomenon known as ‛cross‐decoration'. In contrast, donor liver‐derived EVs are associated with organ tolerance in small animal models. Therefore, the cellular source of EVs and their cargo could influence their downstream immunological effects. To investigate the immunological effects of EVs released by the liver in a physiological and transplant‐relevant model, we isolated EVs being produced during normothermic ex vivo liver perfusion (NEVLP), a novel method of liver storage prior to transplantation. We found EVs were produced by the liver during NEVLP, and these EVs contained multiple anti‐inflammatory miRNA species. In terms of function, liver‐derived EVs were able to cross‐decorate allogeneic cells and suppress the immune response in allogeneic mixed lymphocyte reactions in a concentration‐dependent fashion. In terms of cytokine response, the addition of 1 × 109 EVs to the mixed lymphocyte reactions significantly decreased the production of the inflammatory cytokines TNF‐α, IL‐10 and IFN‐γ. In conclusion, we determined physiologically produced liver‐derived EVs are immunologically regulatory, which has implications for their role and potential modification in solid organ transplantation. [ABSTRACT FROM AUTHOR]

Ferroptosis is an iron‐dependent cell death form that initiates lipid peroxidation (LPO) in tumors. In recent years, there has been growing interest on ferroptosis, but how to propel it forward translational medicine remains in mist. Although experimental ferroptosis inducers such as RSL3 and erastin have demonstrated bioactivity in vitro, the poor antitumor outcome in animal model limits their development. In this study, we reveal a novel ferroptosis inducer, oxaliplatin–artesunate (OART), which exhibits substantial bioactivity in vitro and vivo, and we verify its feasibility in cancer immunotherapy. For mechanism, OART induces cytoplasmic and mitochondrial LPO to promote tumor ferroptosis, via inhibiting glutathione‐mediated ferroptosis defense system, enhancing iron‐dependent Fenton reaction, and initiating mitochondrial LPO. The destroyed mitochondrial membrane potential, disturbed mitochondrial fusion and fission, as well as downregulation of dihydroorotate dehydrogenase mutually contribute to mitochondrial LPO. Consequently, OART enhances tumor immunogenicity by releasing damage associated molecular patterns and promoting antigen presenting cells maturation, thereby transforming tumor environment from immunosuppressive to immunosensitive. By establishing in vivo model of tumorigenesis and lung metastasis, we verified that OART improves the systematic immune response. In summary, OART has enormous clinical potential for ferroptosis‐based cancer therapy in translational medicine. [ABSTRACT FROM AUTHOR]

Immunisation of the newborn represents a key global strategy in overcoming morbidity and mortality due to infection in early life. Potential limitations, however, include poor immunogenicity, safety concerns and the development of tolerogenicity or hypo-responsiveness to either the same antigen and/or concomitant antigens administered at birth or in the subsequent months. Furthermore, the neonatal immunological milieu is polarised towards Th2-type immunity with dampening of Th1-type responses and impaired humoral immunity, resulting in qualitatively and quantitatively poorer antibody responses compared to older infants. Innate immunity also shows functional deficiency in antigen-presenting cells: the expression and signalling of Toll-like receptors undergo maturational changes associated with distinct functional responses. Nevertheless, the effectiveness of BCG, hepatitis B and oral polio vaccines, the only immunisations currently in use in the neonatal period, is proof of concept that vaccines can be successfully administered to the newborn via different routes of delivery to induce a range of protective mechanisms for three different diseases. In this review paper, we discuss the rationale for and challenges to neonatal immunisation, summarising progress made in the field, including lessons learnt from newborn vaccines in the pipeline. Furthermore, we explore important maternal, infant and environmental co-factors that may impede the success of current and future neonatal immunisation strategies. A variety of approaches have been proposed to overcome the inherent regulatory constraints of the newborn innate and adaptive immune system, including alternative routes of delivery, novel vaccine configurations, improved innate receptor agonists and optimised antigen-adjuvant combinations. Crucially, a dual strategy may be employed whereby immunisation at birth is used to prime the immune system in order to improve immunogenicity to subsequent homologous or heterologous boosters in later infancy. Similarly, potent non-specific immunomodulatory effects may be elicited when challenged with unrelated antigens, with the potential to reduce the overall risk of infection and allergic disease in early life. [ABSTRACT FROM AUTHOR]

Fasciola hepatica are trematodes that reside in the bile ducts of mammals. Infection causes US$3 billion in losses annually in animal production and is considered a zoonosis of growing importance. An under-represented area in F. hepatica research has been the examination of the different immunomodulatory abilities of various parasite isolates on the host immune system. In this paper, this issue was explored, with the bovine macrophage cell line 'BOMA'. The cells were matured by LPS treatment and stimulated with excretory/secretory antigens (ES) from two Fasciola hepatica isolates: a laboratory isolate 'Weybridge' ( Fh-WeyES) and a wild isolate ( Fh-WildES). As expected, stimulation with antigen mixtures with highly similar compositions resulted in mild transcriptomic differences. However, there were significant differences in cytokine levels. Compared to Fh-WeyES, exposure to Fh-WildES upregulated 27 and downregulated 30 genes. Fh-ES from both isolates diminished the release of TNF-α, whereas only Fh-WildES decreased IL-10 secretion. Neither Fh-WeyES nor Fh-WildES had an impact on IL-12 release. Our results indicate that various isolates can have different immunomodulatory abilities and impacts on the bovine immune system. [ABSTRACT FROM AUTHOR]

Oncolytic viruses and combinatorial immunotherapy for cancer (this Special Issue) are both part of cancer treatment at IOZK. This review focusses on an individual multimodal cancer immunotherapy concept developed by IOZK, Cologne, Germany. The scientific rationale for employing three main components is explained: (i) oncolytic Newcastle disease virus, (ii) modulated electrohyperthermia and (iii) individual tumor antigen and oncolytic virus modified dendritic cell vaccine (IO-VACR). The strategy involves repeated cancer-immunity cycles evoked in cancer patients by systemic oncolytic virus exposure plus hyperthermia pretreatment to induce immunogenic cell death followed by intradermal IO-VACR vaccination. As an example of the experience at IOZK, we present the latest results from combining the immunotherapy with standard treatment of patients suffering from glioblastoma multiforme. The promising clinical results in terms of overall survival benefit of additional individualized multimodal immunotherapy are presented. The cancer-immunity cycle, as introduced 10 years ago, describes key important steps occurring locally at the sites of both tumor and draining lymph nodes. This view is extended here towards systemic events occuring in blood where immunogenic cell death-induced tumor antigens are transported into the bone marrow. For 20 years it has been known that bone marrow is an antigen-responsive organ in which dendritic cells present tumor antigens to T cells leading to immunological synapse formation, tumor antigen-specific T cell activation and memory T cell formation. Bone marrow is known to be the most prominent source of de novo cellular generation in the body and to play an important role for the storage and maintenance of immunological memory. Its systemic activation is recommended to augment cancer-immunity cycles. [ABSTRACT FROM AUTHOR]

Recently, microneedle arrays (MAs) have been developed for painless inoculation of vaccines and possess many prominent advantages, including convenience for inoculation, and exact delivery of vaccine to the exact epidermal and dermal or mucosal compartments which teem with antigen-presenting cells (APCs). Among different types of MAs, while the micro-environmental stimulus-responsive MAs represent one of the developmental trends in the field, the MAs combined with the conventional vaccines that are based on nonvirulent viruses, such as live attenuated or whole inactivated viruses, and antigen-encoding DNA viral vectors, have developed rapidly into the advanced stages, with certain products already on clinical trials. The pre- and clinical research outcomes showed that the painless MA delivery of the conventional vaccines through mammalian skin or mucosa can not only elicit robust systemic and even mucosal immunity to pathogens but also, in certain circumstances, redirect the immune response toward a specific Th1 pathway, resulting in cytotoxic T lymphocytes (CTL) to erase the cell-hidden pathogens, thanks to the robust adjuvant function of MAs exerted through damaging the contacted cells to release dangerous signals. This paper focuses on reviewing the latest research and advancements in MA delivery of the conventional vaccines that are based on nonvirulent viruses, underlining MA enhancement of the overall vaccine performance and the most advanced MA vaccine products that are relatively close to markets. [ABSTRACT FROM PUBLISHER]

MR1-restricted T cells have been implicated in microbial infections, sterile inflammation, wound healing and cancer. Similar to other antigen presentation molecules, evidence supports multiple, complementary MR1 antigen presentation pathways. To investigate ligand exchange pathways for MR1, we used MR1 monomers and tetramers loaded with 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU) to deliver the antigen. Using MR1-deficient cells reconstituted with wild-type MR1 or MR1 molecules that cannot bind 5-OP-RU, we show that presentation of monomer-delivered 5-OP-RU is dependent on cellular MR1 and requires the transfer of ligand from the soluble molecule onto MR1 expressed by the antigen presenting cell. This mode of antigen delivery strengthens the evidence for post-ER ligand exchange pathways for MR1, which could represent an important avenue by which MR1 acquires antigens derived from endocytosed pathogens. Delivering MR1 ligand in the context of an MR1 monomer demonstrates transfer of this ligand onto cellular MR1. The stabilization of an inherently unstable ligand in the monomer has implications for antigen delivery and possibly vaccine design. [ABSTRACT FROM AUTHOR]

Background: The HLA complex is the most polymorphic region of the human genome, and its improved characterization can help us understand the genetics of human disease as well as the interplay between cancer and the immune system. The main function of HLA genes is to recognize "non-self" antigens and to present them on the cell surface to T cells, which instigate an immune response toward infected or transformed cells. While sequence variation in the antigen-binding groove of HLA may modulate the repertoire of immunogenic antigens presented to T cells, alterations in HLA expression can significantly influence the immune response to pathogens and cancer. Methods: RNA sequencing was used here to accurately genotype the HLA region and quantify and compare the level of allele-specific HLA expression in tumors and patient-matched adjacent normal tissue. The computational approach utilized in the study types classical and non-classical Class I and Class II HLA alleles from RNA-seq while simultaneously quantifying allele-specific or personalized HLA expression. The strategy also uses RNA-seq data to infer immune cell infiltration into tumors and the corresponding immune cell composition of matched normal tissue, to reveal potential insights related to T cell and NK cell interactions with tumor HLA alleles. Results: The genotyping method outperforms existing RNA-seq-based HLA typing tools for Class II HLA genotyping. Further, we demonstrate its potential for studying tumor-immune interactions by applying the method to tumor samples from two different subtypes of breast cancer and their matched normal breast tissue controls. Conclusions: The integrative RNA-seq-based HLA typing approach described in the study, coupled with HLA expression analysis, neoantigen prediction and immune cell infiltration, may help increase our understanding of the interplay between a patient's tumor and immune system; and provide further insights into the immune mechanisms that determine a positive or negative outcome following treatment with immunotherapy such as checkpoint blockade. [ABSTRACT FROM AUTHOR]

Ubiquitination is a process that dictates the lifespan of major histocompatibility complex class II (MHC II)/peptide complexes on antigen-presenting cells. This process is tightly controlled by the levels of ubiquitin ligases, and disruptions in the turnover of MHC II can lead to the improper development of CD4+ T cells within the thymus and hinder the formation of regulatory T cells in the peripheral tissue. To investigate the underlying mechanisms, we utilized dendritic cells lacking the Membrane-associated RING-CH (MARCH) I ubiquitin ligase. We discovered that the overexpression of MARCH I decreases the interaction with LAG-3. Moreover, the MHC II molecules tethered with ubiquitin also showed diminished binding to LAG-3. We employed Diffracted X-ray Blinking (DXB), a technique used for single-molecule X-ray imaging, to observe the protein movements on live cells in real time. Our observations indicated that the normal MHC II molecules moved more rapidly across the cell surface compared to those on the MARCH I-deficient dendritic cells or MHC II KR mutants, which is likely a result of ubiquitination. These findings suggest that the signaling from ubiquitinated MHC II to the T cell receptor differs from the non-ubiquitinated forms. It appears that ubiquitinated MHC II might not be quickly internalized, but rather presents antigens to the T cells, leading to a range of significant immunological responses. [ABSTRACT FROM AUTHOR]

B cell antigen receptor (BCR) signaling induces actin cytoskeleton remodeling by stimulating actin severing, actin polymerization, and the nucleation of branched actin networks via the Arp2/3 complex. This enables B cells to spread on antigen-bearing surfaces in order to increase antigen encounters and to form an immune synapse (IS) when interacting with antigen-presenting cells (APCs). Although the WASp, N-WASp, and WAVE nucleation-promoting factors activate the Arp2/3 complex, the role of WAVE2 in B cells has not been directly assessed. We now show that both WAVE2 and the Arp2/3 complex localize to the peripheral ring of branched F-actin when B cells spread on immobilized anti-Ig antibodies. The siRNA-mediated depletion of WAVE2 reduced and delayed B cell spreading on immobilized anti-Ig, and this was associated with a thinner peripheral F-actin ring and reduced actin retrograde flow compared to control cells. Depleting WAVE2 also impaired integrin-mediated B cell spreading on fibronectin and the LFA-1-induced formation of actomyosin arcs. Actin retrograde flow amplifies BCR signaling at the IS, and we found that depleting WAVE2 reduced microcluster-based BCR signaling and signal amplification at the IS, as well as B cell activation in response to antigen-bearing cells. Hence, WAVE2 contributes to multiple actin-dependent processes in B lymphocytes. [ABSTRACT FROM AUTHOR]

• MR1, a non-polymorphic ubiquitous antigen presenting molecule presents small metabolites to T cells. • MR1T cells recognize small drugs and microbial metabolites presented by MR1. • MR1T cells also recognize self-metabolites accumulating in tumor cells. • MR1T cells are multi-functional and express polyclonal TCR heterodimers. MR1 is an MHC class I-like molecule with unique structural and biological features that make it an important member among the molecules involved in antigen presentation to T cells. Distinctive features include ubiquitous expression of the MR1 gene and its monomorphism. Another relevant property is that the MR1 protein appears at very low levels on the plasma membrane and its surface expression is regulated by antigen binding. Finally, the nature of presented antigens differs from those that bind other presenting molecules and includes small metabolites of microbial and self-origin, small drugs and tumor-associated antigens. This opinion paper describes in detail some of those features and discusses recent literature in the field. [ABSTRACT FROM AUTHOR]

The differences in behaviour between individual cells in a large population are often important, yet are masked in bulk analyses where only average parameters are measured. One unresolved question in the field of immunology is the extent to which important immunological phenomena such as immunodominance to cancer antigens correlates with the average activity of a population of antigen-specific T lymphocytes, or with the activity of individual "outlier" cells. Despite progress in single cell technologies, few platforms are available that can deliver time-resolved, functional analysis at single cell resolution, for these investigations. We have developed an accessible high-throughput platform to measure single T cell signalling in real time following time-controlled stimulation by live antigen presenting cells. The cell-trap array consists of thousands of individual microwells cast in an agarose block, which is biocompatible and permeable to nutrients. Single T cells are isolated in wells via passive sedimentation and size exclusion, achieving up to 90% occupancy. The device enables simultaneous activation of thousands of single CD8+ cells. Stimulation with soluble reagents (ionomycin, anti-CD3 antibodies) or antigen presenting cells leads to changes in intracellular calcium concentrations which were measured using calcium-chelating fluorophore dyes. The platform was used to demonstrate a range of activation profiles among individual cells of a cloned, antigen specific CD8+ T cell hybridoma in response to both nonspecific stimuli and specific, physiologically relevant antigen stimulation. The presence of two different activation profiles was demonstrated, together with rare outlier behaviour among cells that are essentially clonal. [ABSTRACT FROM AUTHOR]

The Dendritic Cell Algorithm (DCA) is an immune-inspired algorithm based on the behavior of natural dendritic cells. The DCA, as a binary classifier, classifies in a crisp manner each data item as either normal or anomalous. However, it was shown that DCA is sensitive to the input class data order. This problem was solved by the development of the fuzzy dendritic cell algorithm. The performance of the latter algorithm relies on its parameters tuning as this process is based on the use of a fuzzy clustering technique. We, thus, believe that the choice of the right fuzzy clustering technique is crucial for the system. In this paper, we try to review the fuzzy version of DCA and to investigate its performance when hybridized with different fuzzy clustering techniques. The aim of this hybridization is to select the most appropriate fuzzy clustering approach in order to generate an overall automated robust fuzzy DCA classifier. [ABSTRACT FROM AUTHOR]

Self-adjuvanting vaccines, consisting of recombinant protein antigens and covalently attached Toll-like receptor (TLR) agonists, have the ability to simultaneously and efficiently deliver antigen and TLR adjuvant to antigen presenting cells (APCs). Here, an enzyme-mediated ligation approach was used to overcome difficulties in producing homogeneous, molecularly defined self-adjuvanting vaccine products under native conditions. This process was optimized to allow the incorporation of the lipopeptide TLR2 agonist fibroblast-stimulating lipopeptide (FSL)-1 onto the N- or C-termini of recombinant protein antigens, employing the enzyme Staphylococcus aureus sortase A (SrtAsa) penta mutant. In addition, because SrtAsamediated ligations are reversible, a tryptophan zipper derived sequence was introduced into both reactants, which was demonstrated to improve ligation efficiency through the formation of a β-hairpin structure that hinders the reverse reaction. Finally, it was demonstrated that N- or C-terminal conjugation, and the incorporation of the β-hairpin structure, did not affect the TLR2-agonist activities of protein antigen TLR agonist conjugates. Overall, this SrtAsa-mediated ligation platform enabled production of antigen TLR2 agonist conjugates with enhanced ligation efficiency, with the conjugates demonstrating potent TLR2 signaling activation (EC50<1nM). [ABSTRACT FROM AUTHOR]

In this paper, the experimental activity was carried out on five pulverized coals with different particle sizes taken from the industrial demonstration plant of SE-Gasifier Pulverized Coal Gasification in Nanjing, China. Flow properties of pulverized coal including powder cohesion, angle of internal friction and tensile strength were determined by the rotational shear cell accessory of Freeman FT4 Powder Rheometer. These pulverized coal samples were further discharged from a bench-scale discharge system and an industrial device in the SE gasification industrial plant. The effects of mean particle size, fine contents and hopper pressure on the flow properties and the discharge of pulverized coal were discussed. The tensile strength was used to correlate with the feeding characteristics of pulverized coal and proved to be an effective indicator to describe the powder feeding performance. A combination of a continuum approach and a particle–particle approach was therefore built to predict the tensile strength. The model, considered the elastic deformation, was further modified by taking into account the effect of particle size distribution. The predicted tensile strengths were compared with those obtained from the Mohr-Coulomb approach, giving errors mostly below ±25%. It was therefore considered as a valuable way to provide reference for the evaluation of feeding characteristics of pulverized coal for entrained-flow gasification. Unlabelled Image • Pulverized coal was taken from the industrial demonstration plant. • Flow properties and discharge behaviors of pulverized coal were determined. • Tensile strength was correlate with powder feeding performance. • A modified model was built to predict tensile strength. [ABSTRACT FROM AUTHOR]

Presentation of exogenous antigens loaded on major histocompatibility complex class I molecules by antigen presenting cells, termed cross-presentation, is essential for the induction of CD8+ T cells and is performed mainly by specialized dendritic cell subsets. Research into this field has described two main mechanisms of cross-presentation, the cytosolic pathway and the vacuolar pathway. As the first step in cross-presentation, surface receptors relating to cross-presentation are required in the recognition and uptake of Ags, which include C-type lectin receptors, immunoglobulin γ Fc region receptor, chemokine receptor, scavenger receptor etc. After uptake by the cells, there are also many molecules that enable Ags to participate in cross-presentation pathways. By this approach, exogenous Ags can induce CD8+ T cells into cytotoxic T lymphocytes, which is of great significance to induce antitumor and antiviral immune responses, and the molecular mechanism would facilitate the development of related adjuvants. However, the detailed mechanisms of cross-presentation still remain unknown. In this paper, some latest researches, including two major pathways, DC surface receptors and application prospects are summarized. [ABSTRACT FROM AUTHOR]

Photoreceptor cells (PRCs) across the animal kingdom are characterized by a stacking of apical membranes to accommodate the high abundance of photopigment. In arthropods and many other invertebrate phyla PRC membrane stacks adopt the shape of densely packed microvilli that form a structure called rhabdomere. PRCs and surrounding accessory cells, including pigment cells and lens-forming cells, are grouped in stereotyped units, the ommatidia. In larvae of holometabolan insects, eyes (called stemmata) are reduced in terms of number and composition of ommatidia. The stemma of Drosophila (Bolwig organ) is reduced to a bilateral cluster of subepidermal PRCs, lacking all other cell types. In the present paper we have analyzed the development and fine structure of the Drosophila larval PRCs. Shortly after their appearance in the embryonic head ectoderm, PRC precursors delaminate and lose expression of apical markers of epithelial cells, including Crumbs and several centrosome-associated proteins. In the early first instar larva, PRCs show an expanded, irregularly shaped apical surface that is folded into multiple horizontal microvillar-like processes (MLPs). Apical PRC membranes and MLPs are covered with a layer of extracellular matrix. MLPs are predominantly aligned along an axis that extends ventro-anteriorly to dorso-posteriorly, but vary in length, diameter, and spacing. Individual MLPs present a "beaded" shape, with thick segments (0.2–0.3 μm diameter) alternating with thin segments (>0.1 μm). We show that loss of the glycoprotein Chaoptin, which is absolutely essential for rhabdomere formation in the adult PRCs, does not lead to severe abnormalities in larval PRCs. • We reconstruct the photoreceptors (PRCs) of the Bolwig Organ (BO) using serial EM. • BO PRCs do not form a rhabdomere but extend long microvillar-like processes (MLPs). • MLPs extend roughly parallel to each other and cover the former apical PRC surface. • MLPs are long and unbranched, with thick segments alternating with thin segments. [ABSTRACT FROM AUTHOR]

Background: Control of Tuberculosis (TB) infection is mainly the result of productive teamwork between T-cell populations and antigen presenting cells (APCs). However, APCs activation at the site of initiating cellular immune response during BCG early infection is not completely understood. Methods: In this study, we injected C57BL/6 mice in intravenous (i.v) or subcutaneous (s.c) route, then splenic or inguinal lymph node (LN) DCs and MΦs were sorted, and mycobacteria uptake, cytokine production, antigen presentation activity, and cell phenotype were investigated and compared, respectively. Results: Ag85A-specific T-cell immune response began at 6 days post BCG infection, when BCG was delivered in s.c route, Th17 immune response could be induced in inguinal LN. BCG could induce high level of activation phenotype in inguinal LN MΦs, while the MHC II presentation of mycobacteria-derived peptides by DCs was more efficient than MΦs. Conclusions: The results showed that BCG immunized route can decide the main tissue of T-cell immune response. Compared with s.c injected route, APCs undergo more rapid cell activation in spleen post BCG i.v infection. [ABSTRACT FROM AUTHOR]

The African swine fever (ASF) pandemics pose a significant threat to the global swine industry, and the development of safe and effective vaccines is a daunting but necessary challenge. The level and persistence of immunity are very important for the effectiveness of the vaccine. Targeting antigens to antigen presenting cells (APCs) can greatly enhance immunogenicity. In this study, we developed a self-assembled nano-ASFV vaccine candidate (NanoFVax) targeting DCs, by covalently coupling the self-assembled 24-mer ferritin with the dominant B and T cell epitopes of the highly immunogenic ASFV antigen (p72, CD2v, pB602L and p30) and fused with the chemokine receptor XCL1 (a DC targeting molecule) through the SpyTag/SpyCatcher protein ligase system. Compared to monomeric protein, the nanoparticle vaccines can induce a more robust T-cell response, and the high-level antibody response against ASFV can last for more than 231 days. Therefore, the NanoFVax is a novel and promising vaccine candidate for ASFV. [ABSTRACT FROM AUTHOR]

Efficacy of cancer vaccines remains low and mechanistic understanding of antigen presenting cell function in cancer may improve vaccine design and outcomes. Here, we analyze the transcriptomic and immune-metabolic profiles of Dendritic Cells (DCs) from 35 subjects enrolled in a trial of DC vaccines in late-stage melanoma (NCT01622933). Multiple platforms identify metabolism as an important biomarker of DC function and patient overall survival (OS). We demonstrate multiple immune and metabolic gene expression pathway alterations, a functional decrease in OCR/OXPHOS and increase in ECAR/glycolysis in patient vaccines. To dissect molecular mechanisms, we utilize single cell SCENITH functional profiling and show patient clinical outcomes (OS) correlate with DC metabolic profile, and that metabolism is linked to immune phenotype. With single cell metabolic regulome profiling, we show that MCT1 (monocarboxylate transporter-1), a lactate transporter, is increased in patient DCs, as is glucose uptake and lactate secretion. Importantly, pre-vaccination circulating myeloid cells in patients used as precursors for DC vaccine generation are significantly skewed metabolically as are several DC subsets. Together, we demonstrate that the metabolic profile of DC is tightly associated with the immunostimulatory potential of DC vaccines from cancer patients. We link phenotypic and functional metabolic changes to immune signatures that correspond to suppressed DC differentiation. Efficacy of dendritic cell (DC)-based vaccines remains unsatisfactory. Here the authors analyse the transcriptomic and immune-metabolic profiles of DCs from patients enrolled in a DC vaccine trial in late-stage melanoma, suggesting that the metabolic profile of DC is associated with the immunostimulatory potential of the cancer vaccine. [ABSTRACT FROM AUTHOR]

This study aimed to confirm the reality of family-focused medical treatment of dementia in Japan and the US. It conducted a questionnaire survey on informed consent from patients with dementia among neurologists and psychiatrists in four prefectures in the Tokai Region (Aichi, Gifu, Mie, and Shizuoka) and dementia specialists in the US. Of the responses, 120 (39.7% response rate) and 20 (5.9% response rate) were obtained, respectively. In obtaining informed consent from patients with dementia, 75 Japanese specialists (62.5%) and 16 US specialists (80.0%) regularly assessed patients’ decision-making abilities. The majority of specialists in both Japan and the US used the Mini–Mental State Examination and Hierarchic Dementia Scale-Revised, which are widely used for cognitive function assessment. In the survey, 27 Japanese specialists (22.5%) and 10 US specialists (50.0%) had different considerations when obtaining informed consent for participation in research, compared to their medical practice. The majority of Japanese and US specialists obtained informed consent from both the patient and their family. [ABSTRACT FROM AUTHOR]

Human leukocyte antigen (HLA)-DPB1 antigens are mismatched in approximately 70% of allogeneic hematopoietic stem cell transplantations (allo-HSCT) from HLA 10/10 matched unrelated donors. HLADP-mismatched transplantation was shown to be associated with an increase in acute graft-versus-host disease (GVHD) and a decreased risk of leukemia relapse due to the graft-versus-leukemia (GVL) effect. Immunotherapy targeting mismatched HLA-DP is considered reasonable to treat leukemia following alloHCT if performed under non-inflammatory conditions. Therefore, we isolated CD4+ T cell clones that recognize mismatched HLA-DPB1 from healthy volunteer donors and generated T cell receptor (TCR)- gene-modified T cells for future clinical applications. Detailed analysis of TCR-T cells expressing TCR from candidate clone #17 demonstrated specificity to myeloid and monocytic leukemia cell lines that even expressed low levels of targeted HLA-DP. However, they did not react to non-hematopoietic cell lines with a substantial level of targeted HLA-DP expression, suggesting that the TCR recognized antigenic peptide is only present in some hematopoietic cells. This study demonstrated that induction of T cells specific for HLA-DP, consisting of hematopoietic cell lineage-derived peptide and redirection of T cells with cloned TCR cDNA by gene transfer, is feasible when using careful specificity analysis. [ABSTRACT FROM AUTHOR]

The influence of aging on intestinal stem cells and their niche can explain underlying causes for perturbation in their function observed during aging. Molecular mechanisms for such a decrease in the functionality of intestinal stem cells during aging remain largely undetermined. Using transcriptome-wide approaches, our study demonstrates that aging intestinal stem cells strongly upregulate antigen presenting pathway genes and over-express secretory lineage marker genes resulting in lineage skewed differentiation into the secretory lineage and strong upregulation of MHC class II antigens in the aged intestinal epithelium. Mechanistically, we identified an increase in proinflammatory cells in the lamina propria as the main source of elevated interferon gamma (IFNγ) in the aged intestine, that leads to the induction of Stat1 activity in intestinal stem cells thus priming the aberrant differentiation and elevated antigen presentation in epithelial cells. Of note, systemic inhibition of IFNγ-signaling completely reverses these aging phenotypes and reinstalls regenerative capacity of the aged intestinal epithelium. Omrani, Krepelova et al. report that aging-induced proinflammatory IFNγ/Stat1 signalling primes intestinal stem cells to a secretory fate and to antigen presenting cells impairing the regenerative capacity of the aging gut epithelium. [ABSTRACT FROM AUTHOR]

Simple Summary: Tyrosine phosphorylation is the first biochemical event that occurs after TCR engagement, which is crucial for T-cell development, activation and differentiation. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. The negative regulation of these early signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in the TCR-signaling cassette, both of their functions in activation signal transduction and the negative-feedback loops in which they participate. A better knowledge of these negative regulatory mechanisms may be critical not only for understanding T-cell activation, but also for a more efficient design of therapeutic approaches and a better understanding of some immune-based pathologies. Specific antigen recognition is one of the immune system's features that allows it to mount intense yet controlled responses to an infinity of potential threats. T cells play a relevant role in the host defense and the clearance of pathogens by means of the specific recognition of peptide antigens presented by antigen-presenting cells (APCs), and, to do so, they are equipped with a clonally distributed antigen receptor called the T-cell receptor (TCR). Upon the specific engagement of the TCR, multiple intracellular signals are triggered, which lead to the activation, proliferation and differentiation of T lymphocytes into effector cells. In addition, this signaling cascade also operates during T-cell development, allowing for the generation of cells that can be helpful in the defense against threats, as well as preventing the generation of autoreactive cells. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. These early signals play a relevant role in triggering the development, activation, proliferation and apoptosis of T cells, and the negative regulation of these signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we will examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in these cellular processes. [ABSTRACT FROM AUTHOR]

Fasciola hepatica is a fluke that infects livestock and humans causing fasciolosis, a zoonotic disease of increasing importance due to its worldwide distribution and high economic losses. The parasite regulates the host immune system by inducing a strong Th2 and regulatory T (Treg) cell immune response through mechanisms that might involve the expression or activity of heme-oxygenase-1 (HO-1), the rate-limiting enzyme in the catabolism of free heme that also has immunoregulatory and antioxidant properties. In this paper, we show that F. hepatica-infected mice upregulate HO-1 on peritoneal antigen-presenting cells (APC), which produce decreased levels of both reactive oxygen and nitrogen species (ROS/RNS). The presence of these cells was associated with increased levels of regulatory T cells (Tregs). Blocking the IL-10 receptor (IL-10R) during parasite infection demonstrated that the presence of splenic Tregs and peritoneal APC expressing HO-1 were both dependent on IL-10 activity. Furthermore, IL-10R neutralization as well as pharmacological treatment with the HO-1 inhibitor SnPP protected mice from parasite infection and allowed peritoneal APC to produce significantly higher ROS/RNS levels than those detected in cells from infected control mice. Finally, parasite infection carried out in gp91phox knockout mice with inactive NADPH oxidase was associated with decreased levels of peritoneal HO-1+ cells and splenic Tregs, and partially protected mice from the hepatic damage induced by the parasite, revealing the complexity of the molecular mechanisms involving ROS production that participate in the complex pathology induced by this helminth. Altogether, these results contribute to the elucidation of the immunoregulatory and antioxidant role of HO-1 induced by F. hepatica in the host, providing alternative checkpoints that might control fasciolosis. [ABSTRACT FROM AUTHOR]

This paper reports the protandric hermaphroditic changes in the reproductive system of the malephased Norileca indica, a cymothoid that parasitizes the scombrid fish Rastrelliger kanagurta. Each part of N. indica’s paired reproductive system lies on either side of the gut. This study considers the three successive size classes of the male phase – designated as M1, M2 and M3 – using light microscopy and ultrastructural methods. The testis comprises of three bulged sac-like lobes labelled t1, t2 and t3, all of which open into the ovary of their respective side. The vas deferens, which emerges as a posterior extension of the ovary, opens into the penis and the distal end of each oviduct leads to a sealed gonopore on their respective sides. Each testis lobe (t1/t2/t3) displays clusters of germ cells undergoing stage-specific differentiation. Spermatids undergoing sequential changes associated with spermiogenesis keep close proximity to somatic accessory cells. The characteristic histological changes associated with protandric hermaphroditism are visible in the ovaries of sequential size classes (M1, M2 and M3). In early M1, besides spermatophores, the ovary has abundant polymorphic nuclei; in the mid/late M1, the posterior ovary has abundant spermatophores, anterior displayed oogonia, previtellogenic oocytes and two distinct forms of follicle cells. In M2, the anterior ovary shows compactly arranged oocytes while the posterior region accommodates spermatophores – fewer, however, than during M1. The entire ovary during M3 is crowded with previtellogenic oocytes, which marginalize the spermatophore passage. The vas deferens of the smallest M1 lack spermatophores. As the size class progresses through late M1 into M2 and M3, the posterior vas deferens is filled with spermatophores, which closely associate with the glandular epithelial lining. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus superantigens (SAgs) such as staphylococcal enterotoxin A (SEA) and B (SEB) are potent toxins stimulating T cells to produce high levels of inflammatory cytokines, thus causing toxic shock and sepsis. Here we used a recently released artificial intelligence-based algorithm to better elucidate the interaction between staphylococcal SAgs and their ligands on T cells, the TCR and CD28. The obtained computational models together with functional data show that SEB and SEA are able to bind to the TCR and CD28 stimulating T cells to activate inflammatory signals independently of MHC class II- and B7-expressing antigen presenting cells. These data reveal a novel mode of action of staphylococcal SAgs. By binding to the TCR and CD28 in a bivalent way, staphylococcal SAgs trigger both the early and late signalling events, which lead to massive inflammatory cytokine secretion. [ABSTRACT FROM AUTHOR]

T cells form transient cell-to-cell contacts with antigen presenting cells (APCs) to facilitate surface interrogation by membrane bound T cell receptors (TCRs). Upon recognition of molecular signatures (antigen) of pathogen, T cells may initiate an adaptive immune response. The duration of the T cell/APC contact is observed to vary widely, yet it is unclear what constructive role, if any, such variations might play in immune signaling. Modeling efforts describing antigen discrimination often focus on steady-state approximations and do not account for the transient nature of cellular contacts. Within the framework of a kinetic proofreading (KP) mechanism, we develop a stochastic First Receptor Activation Model (FRAM) describing the likelihood that a productive immune signal is produced before the expiry of the contact. Through the use of extreme statistics, we characterize the probability that the first TCR triggering is induced by a rare agonist antigen and not by that of an abundant self-antigen. We show that defining positive immune outcomes as resilience to extreme statistics and sensitivity to rare events mitigates classic tradeoffs associated with KP. By choosing a sufficient number of KP steps, our model is able to yield single agonist sensitivity whilst remaining non-reactive to large populations of self antigen, even when self and agonist antigen are similar in dissociation rate to the TCR but differ largely in expression. Additionally, our model achieves high levels of accuracy even when agonist positive APCs encounters are rare. Finally, we discuss potential biological costs associated with high classification accuracy, particularly in challenging T cell environments. Author summary: Physical contact between the T cell and antigen presenting cell (APC) is essential for productive immune signaling. Wide variations in this contact time have been observed yet little is known of mechanisms controlling this crucial timescale, nor how its duration may impact antigen discrimination. We develop and analyze a probabilistic mathematical model of T cell activation which combines kinetic proofreading (KP) with a finite contact duration. Our model is capable of suppressing large populations of self ligands while remaining sensitive to only a single agonist in T cell/APC cellular contacts. Additionally, we explored two challenging cases, one in which self and agonist antigen are similar and one in which agonist positive APCs are rare. We found that our model could overcome these environmental challenges by increasing the number of kinetic proofreading steps. Finally, we discuss the potential biological costs of achieving such accuracy. Our work demonstrates the extreme effectiveness of kinetic proofreading in a temporal context while also demonstrating the possible challenges in biological implementation of such a model. [ABSTRACT FROM AUTHOR]

Background: Giant Cell Arteritis (GCA) and Polymyalgia Rheumatica (PMR) are overlapping inflammatory diseases. Antigen-presenting cells (APCs), including monocytes and dendritic cells (DCs), are main contributors to the immunopathology of GCA and PMR. However, little is known about APC phenotypes in the peripheral blood at the time of GCA/PMR diagnosis. Methods: APCs among peripheral blood mononuclear cells (PBMCs) of treatment-naive GCA and PMR patients were compared to those in age- and sex-matched healthy controls (HCs) using flow cytometry (n=15 in each group). We identified three monocyte subsets, and three DC subsets: plasmacytoid DCs (pDCs), CD141+ conventional DCs (cDC1) and CD1c+ conventional DCs (cDC2). Each of these subsets was analyzed for expression of pattern recognition receptors (TLR2, TLR4), immune checkpoints (CD86, PDL1, CD40) and activation markers (HLA-DR, CD11c). Results: t-SNE plots revealed a differential clustering of APCs between GCA/PMR and HCs. Further analyses showed shifts in monocyte subsets and a lower proportion of the small population of cDC1 cells in GCA/PMR, whereas cDC2 proportions correlated negatively with CRP (r=-0.52). Classical monocytes of GCA/PMR patients show reduced expression of TLR2, HLA-DR, CD11c, which was in contrast to non-classical monocytes that showed higher marker expression. Additionally, single cell RNA sequencing in GCA patients identified a number of differentially expressed genes related to inflammation and metabolism in APCs. Conclusion: Circulating non-classical monocytes display an activated phenotype in GCA/PMR patients at diagnosis, whereas classical monocytes show reduced expression of activation markers. Whether these findings reflect APC migration patterns or the effects of long-term inflammation remains to be investigated. [ABSTRACT FROM AUTHOR]

Introduction: The majority of studies on oxidative phosphorylation in immune cells have been performed in mouse models, necessitating human translation. To understand the impact of oxidative phosphorylation (OXPHOS) deficiency on human immunity, we studied children with primary mitochondrial disease (MtD). Methods: scRNAseq analysis of peripheral blood mononuclear cells was performed on matched children with MtD (N = 4) and controls (N = 4). To define B cell function we performed phage display immunoprecipitation sequencing on a cohort of children with MtD (N = 19) and controls (N = 16). Results: Via scRNAseq, we found marked reductions in select populations involved in the humoral immune response, especially antigen presenting cells, B cell and plasma populations, with sparing of T cell populations. MTRNR2L8, a marker of bioenergetic stress, was significantly elevated in populations that were most depleted. mir4485, a miRNA contained in the intron of MTRNR2L8, was coexpressed. Knockdown studies of mir4485 demonstrated its role in promoting survival by modulating apoptosis. To determine the functional consequences of our findings on humoral immunity, we studied the antiviral antibody repertoire in children with MtD and controls using phage display and immunoprecipitation sequencing. Despite similar viral exposomes, MtD displayed antiviral antibodies with less robust fold changes and limited polyclonality. Discussion: Overall, we show that children with MtD display perturbations in the B cell repertoire which may impact humoral immunity and the ability to clear viral infections. [ABSTRACT FROM AUTHOR]

Influenza B virus (IBV) contributes to substantial influenza-mediated morbidity and mortality, particularly among children. Similar to influenza A viruses (IAV), the hemagglutinin (HA) and neuraminidase (NA) of IBV undergo antigenic drift, necessitating regular reformulation of seasonal influenza vaccines. NA inhibitors, such as oseltamivir, have reduced activity and clinical efficacy against IBV, while M2 channel inhibitors are only effective against IAV, highlighting the need for improved vaccine and therapeutics for the treatment of seasonal IBV infections. We have previously described a potent human monoclonal antibody (hMAb), 1092D4, that is specific for IBV NA and neutralizes a broad range of IBVs. The anti-viral activity of MAbs can include direct mechanisms such as through neutralization and/or Fc-mediated effector functions that are dependent on accessory cells expressing Fc receptors and that could be impacted by potential host-dependent variability. To discern if the in vivo efficacy of 1092D4 was dependent on Fc-effector function, 1092D4 hMAb with reduced ability to bind to Fc receptors (1092D4–LALAPG) was generated and tested. 1092D4–LALAPG had comparable in vitro binding, neutralization, and inhibition of NA activity to 1092D4. 1092D4–LALAPG was effective at protecting against a lethal challenge of IBV in mice. These results suggest that hMAb 1092D4 in vivo activity is minimally dependent on Fc-effector functions, a characteristic that may extend to other hMAbs that have potent NA inhibition activity. [ABSTRACT FROM AUTHOR]

To respond to the world around them, animals rely on the input of a network of sensory organs distributed throughout the body. Distinct classes of sensory organs are specialized for the detection of specific stimuli such as strain, pressure, or taste. The features that underlie this specialization relate both to the neurons that innervate sensory organs and the accessory cells they comprise. To understand the genetic basis of this diversity of cell types, both within and between sensory organs, we performed single-cell RNA sequencing on the first tarsal segment of the male Drosophila melanogaster foreleg during pupal development. This tissue displays a wide variety of functionally and structurally distinct sensory organs, including campaniform sensilla, mechanosensory bristles, and chemosensory taste bristles, as well as the sex comb, a recently evolved male-specific structure. In this study, we characterize the cellular landscape in which the sensory organs reside, identify a novel cell type that contributes to the construction of the neural lamella, and resolve the transcriptomic differences among support cells within and between sensory organs. We identify the genes that distinguish between mechanosensory and chemosensory neurons, resolve a combinatorial transcription factor code that defines 4 distinct classes of gustatory neurons and several types of mechanosensory neurons, and match the expression of sensory receptor genes to specific neuron classes. Collectively, our work identifies core genetic features of a variety of sensory organs and provides a rich, annotated resource for studying their development and function. Drosophila melanogaster carry a wide range of specialized sensory organs on the foreleg tarsus; a single-cell atlas of this tissue during pupal development reveals the genetic differences between different sensory organ classes and their constituent cells, as well as a novel cell type associated with the formation of the neural lamella. [ABSTRACT FROM AUTHOR]

Introduction: The ability to modulate and enhance the anti-tumor immune responses is critical in developing novel therapies in cancer. The Tumor Necrosis Factor (TNF) Receptor Super Family (TNFRSF) are potentially excellent targets for modulation which result in specific anti-tumor immune responses. CD40 is a member of the TNFRSF and several clinical therapies are under development. CD40 signaling plays a pivotal role in regulating the immune system from B cell responses to myeloid cell driven activation of T cells. The CD40 signaling axis is well characterized and here we compare next generation HERA-Ligands to conventional monoclonal antibody based immune modulation for the treatment of cancer. Methods & results: HERA-CD40L is a novel molecule that targets CD40 mediated signal transduction and demonstrates a clear mode of action in generating an activated receptor complex via recruitment of TRAFs, cIAP1, and HOIP, leading to TRAF2 phosphorylation and ultimately resulting in the enhanced activation of key inflammatory/survival pathway and transcription factors such asNFkB, AKT, p38, ERK1/2, JNK, and STAT1 in dendritic cells. Furthermore, HERACD40L demonstrated a strong modulation of the tumor microenvironment (TME) via the increase in intratumoral CD8+ T cells and the functional switch from pro-tumor macrophages (TAMs) to anti-tumor macrophages that together results in a significant reduction of tumor growth in a CT26 mouse model. Furthermore, radiotherapy which may have an immunosuppressive modulation of the TME, was shown to have an immunostimulatory effect in combination with HERA-CD40L. Radiotherapy in combination with HERA-CD40L treatment resulted in an increase in detected intratumoral CD4+/8+ T cells compared to RT alone and, additionally, the repolarization of TAMs was also observed, resulting in an inhibition of tumor growth in a TRAMP-C1 mouse model. Discussion: Taken together, HERA-CD40L resulted in activating signal transduction mechanisms in dendritic cells, resulting in an increase in intratumoral T cells and manipulation of the TME to be pro-inflammatory, repolarizing M2 macrophages to M1, enhancing tumor control. [ABSTRACT FROM AUTHOR]