Cellular mechanisms governing cross-presentation of exogenous antigens

Interferon Gamma Inducible Protein 30: from biological functions to potential therapeutic target in cancers

Interferon Gamma Inducible Protein 30 (IFI30), also known as Gamma-Interferon-Inducible Lysosomal Thiol Reductase (GILT), is predominantly found in lysosomes and the cytoplasm. As the sole enzyme identified to catalyze disulfide bond reduction in the endocytic pathway, IFI30 contributes to both major histocompatibility complex (MHC) class I-restricted antigen cross-presentation and MHC class II-restricted antigen processing by decreasing the disulfide bonds of endocytosed proteins. Remarkably, emerging research has revealed that IFI30 is involved in tumorigenesis, tumor development, and the tumor immune response. Targeting IFI30 may provide new strategies for cancer therapy and improve the prognosis of patients. This review provided a comprehensive overview of the research progress on IFI30 in tumor progression, cellular redox status, autophagy, tumor immune response, and drug sensitivity, with a view to providing the theoretical basis for pharmacological intervention of IFI30 in tumor therapy, particularly in immunotherapy.

Decoding Organelle Interactions: Unveiling Molecular Mechanisms and Disease Therapies

Organelles, substructures in the cytoplasm with specific morphological structures and functions, interact with each other via membrane fusion, membrane transport, and protein interactions, collectively termed organelle interaction. Organelle interaction is a complex biological process involving the interaction and regulation of several organelles, including the interaction between mitochondria-endoplasmic reticulum, endoplasmic reticulum-Golgi, mitochondria-lysosomes, and endoplasmic reticulum-peroxisomes. This interaction enables intracellular substance transport, metabolism, and signal transmission, and is closely related to the occurrence, development, and treatment of many diseases, such as cancer, neurodegenerative diseases, and metabolic diseases. Herein, the mechanisms and regulation of organelle interactions are reviewed, which are critical for understanding basic principles of cell biology and disease development mechanisms. The findings will help to facilitate the development of novel strategies for disease prevention, diagnosis, and treatment opportunities.

Macrophages: Key Cellular Players in HIV Infection and Pathogenesis

Although cells of the myeloid lineages, including tissue macrophages and conventional dendritic cells, were rapidly recognized, in addition to CD4+ T lymphocytes, as target cells of HIV-1, their specific roles in the pathophysiology of infection were initially largely neglected. However, numerous studies performed over the past decade, both in vitro in cell culture systems and in vivo in monkey and humanized mouse animal models, led to growing evidence that macrophages play important direct and indirect roles as HIV-1 target cells and in pathogenesis. It has been recently proposed that macrophages are likely involved in all stages of HIV-1 pathogenesis, including virus transmission and dissemination, but above all, in viral persistence through the establishment, together with latently infected CD4+ T cells, of virus reservoirs in many host tissues, the major obstacle to virus eradication in people living with HIV. Infected macrophages are indeed found, very often as multinucleated giant cells expressing viral antigens, in almost all lymphoid and non-lymphoid tissues of HIV-1-infected patients, where they can probably persist for long period of time. In addition, macrophages also likely participate, directly as HIV-1 targets or indirectly as key regulators of innate immunity and inflammation, in the chronic inflammation and associated clinical disorders observed in people living with HIV, even in patients receiving effective antiretroviral therapy. The main objective of this review is therefore to summarize the recent findings, and also to revisit older data, regarding the critical functions of tissue macrophages in the pathophysiology of HIV-1 infection, both as major HIV-1-infected target cells likely found in almost all tissues, as well as regulators of innate immunity and inflammation during the different stages of HIV-1 pathogenesis.

Antigen cross-presentation by dendritic cells: A critical axis in cancer immunotherapy

Dendritic cells (DCs) are professional antigen-presenting cells that play a key role in shaping adaptive immunity. DCs have a unique ability to sample their environment, capture and process exogenous antigens into peptides that are then loaded onto major histocompatibility complex class I molecules for presentation to CD8+ T cells. This process, called cross-presentation, is essential for initiating and regulating CD8+ T cell responses against tumors and intracellular pathogens. In this review, we will discuss the role of DCs in cancer immunity, the molecular mechanisms underlying antigen cross-presentation by DCs, the immunosuppressive factors that limit the efficiency of this process in cancer, and approaches to overcome DC dysfunction and therapeutically promote antitumoral immunity.

An Evaluation of Urease A Subunit Nanocapsules as a Vaccine in a Mouse Model of Helicobacter pylori Infection

Using removable silica templates, protein nanocapsules comprising the A subunit of Helicobacter pylori urease (UreA) were synthesised. The templates were of two sizes, with solid core mesoporous shell (SC/MS) silica templates giving rise to nanocapsules of average diameter 510 nm and mesoporous (MS) silica templates giving rise to nanocapsules of average diameter 47 nm. Both were shown to be highly monodispersed and relatively homogenous in structure. Various combinations of the nanocapsules in formulation were assessed as vaccines in a mouse model of H. pylori infection. Immune responses were evaluated and protective efficacy assessed. It was demonstrated that vaccination of mice with the larger nanocapsules combined with an adjuvant was able to significantly reduce colonisation.

CAR T-Cell Therapy for Cancer: Latest Updates and Challenges, with a Focus on B-Lymphoid Malignancies and Selected Solid Tumours

Although exponential progress in treating advanced malignancy has been made in the modern era with immune checkpoint blockade, survival outcomes remain suboptimal. Cellular immunotherapy, such as chimeric antigen receptor T cells, has the potential to improve this. CAR T cells combine the antigen specificity of a monoclonal antibody with the cytotoxic 'power' of T-lymphocytes through expression of a transgene encoding the scFv domain, CD3 activation molecule, and co-stimulatory domains. Although, very rarely, fatal cytokine-release syndrome may occur, CAR T-cell therapy gives patients with refractory CD19-positive B-lymphoid malignancies an important further therapeutic option. However, low-level expression of epithelial tumour-associated-antigens on non-malignant cells makes the application of CAR T-cell technology to common solid cancers challenging, as does the potentially limited ability of CAR T cells to traffic outside the blood/lymphoid microenvironment into metastatic lesions. Despite this, in advanced neuroblastoma refractory to standard therapy, 60% long-term overall survival and an objective response in 63% was achieved with anti GD2-specific CAR T cells.

Immunological response of 35 and 42 days old Asian seabass (Lates calcarifer, Bloch 1790) fry following immersion immunization with Streptococcus iniae heat-killed vaccine

Early disease prevention by vaccination requires understanding when fry fish develop specific immunity to a given pathogen. In this research, we explored the immune responses of Asian seabass (Lates calcarifer) at the stages of 35- and 42- days post-hatching (dph) to an immersive heat-killed Streptococcus iniae (Si) vaccine to determine whether fish can produce specific antibodies against the pathogen. The vaccinated fish of each stage (V35 and V42) were immersed with the Si vaccine at 10⁷ CFU/ml for 3 h, whereas the control groups (C35 and C42) were immersed with tryptic soy broth (TSB) in the same manner. Specific antibodies were measured by enzyme-linked immunosorbent assay (ELISA) before and post-immunization (i.e., 0, 7, and 14 days post-immunization, dpi). Expression of innate (TNFα and IL-1β) and adaptive (MHCI, MHCII, CD4, CD8, IgM-like, IgT-like, and IgD-like) immune-related genes were evaluated at the same time points with the addition of 1 dpi. The results showed that a subset of immunized fish from both V35 and V42 fry could elicit specific antibodies (IgM) against Si at 14 dpi. All tested innate and adaptive immune genes upregulated at 7 dpi among fish in V35 group. Interestingly, 42 dph fish appeared to respond to the Si vaccine faster than that of 35 dph, as a significant increase in transcripts was observed in CD4, IL-1β, IgM-like, and IgD-like at 1 dpi; and specific antibody titers of some fish, although not all, were higher than a threshold (p = 0.05) since 7 dpi. In conclusion, this study reveals that 35-42 dph Asian seabass fry can elicit specific immunity to Si immersion vaccine, suggesting that early vaccination of 35 dph fry Asian seabass is feasible.

Tuning Bacterial Morphology to Enhance Anticancer Vaccination

Morphology tuning is a potent strategy to modulate physiological effects of synthetic biomaterials, but it is rarely explored in microbe-based biochemicals due to the lack of artificial adjustability. Inspired by the interesting phenomenon of microbial transformation, Escherichia coli is rationally adjusted into filamentous morphology-adjusted bacteria (MABac) via chemical stimulation to prepare a bacteria-based vaccine adjuvant/carrier. Inactivated MABac display stronger immunogenicity and special delivery patterns (phagosome escape and cytoplasmic retention) that are sharply distinct from the short rod-shaped bacteria parent (Bac). Transcriptomic study further offers solid evidence for deeply understanding the in vivo activity of MABac-based vaccine, which more effectively motivates multiple cytosolic immune pathways (such as NOD-like receptors and STING) and induces pleiotropic immune responses in comparison with Bac. Harnessing the special functions caused by morphology tuning, the MABac-based adjuvant/carrier significantly improves the immunogenicity and delivery profile of cancer antigens in vivo, thus boosting cancer-specific immunity against the melanoma challenge. This study validates the feasibility of tuning bacterial morphology to improve their biological effects, establishing a facile engineering strategy that upgrades bacterial properties and functions without complex procedures like gene editing.

Development and Evaluation of Recombinant B-Cell Multi-Epitopes of PDHA1 and GAPDH as Subunit Vaccines against Streptococcus iniae Infection in Flounder (Paralichthys olivaceus)

Streptococcus iniae is a severe Gram-positive pathogen that can infect a wide range of freshwater and marine fish species. In continuation of our earlier studies on the development of S. iniae vaccine candidates, pyruvate dehydrogenase E1 subunit alpha (PDHA1) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were highly efficacious in protecting flounder (Paralichthys olivaceus) against S. iniae. In the present study, to investigate the potential of multi-epitope vaccination strategy to prevent flounder against S. iniae infection, the liner B-cell epitopes of PDHA1 and GAPDH proteins were predicted using a bioinformatics approach and were identified by immunoassay, and recombinant B-cell multi-epitopes of PDHA1 and GAPDH (rMEPIP and rMEPIG) containing immunodominant epitope-concentrated domains were expressed in Escherichia coli BL21 (DE3) and were used as a subunit vaccine to immunize healthy flounder, while recombinant PDHA1 (rPDHA1), GAPDH (rGAPDH) and formalin-inactivated S. iniae (FKC) served as controls. Then, the immunoprotection efficacy of rMEPIP and rMEPIG was evaluated by determining the percentages of CD4-1+, CD4-2+, CD8β+ T lymphocytes and surface-IgM-positive (sIgM+) lymphocytes in peripheral blood leucocytes (PBLs), spleen leucocytes (SPLs) and head kidney leucocytes (HKLs), as well as total IgM, specific IgM, and relative percentage survival (RPS) post immunization, respectively. It was found that fish immunized with rPDHA1, rGAPDH, rMEPIP, rMEPIG and FKC showed significant increases in sIgM+, CD4-1+, CD4-2+, and CD8β+ lymphocytes and production of total IgM and specific IgM against S. iniae or recombinant proteins rPDHA1 and rGAPDH, which indicated the activation of humoral and cellular immune responses after vaccination. Moreover, RPS rate of the multi-epitope vaccine rMEPIP and rMEPIG groups reached 74.07% and 77.78%, higher than that of rPDHA1 and rGAPDH (62.96% and 66.67%) and KFC (48.15%). These results demonstrated that B-cell multi-epitope protein vaccination, rMEPIP and rMEPIG, could give a better protective effect against S. iniae infection, which provided a promising strategy to design the efficient vaccine in teleost fish.

The impact of immunopeptidomics: From basic research to clinical implementation

The immunopeptidome is the set of peptides presented by the major histocompatibility complex (MHC) molecules, in humans also known as the human leukocyte antigen (HLA), on the surface of cells that mediate T-cell immunosurveillance. The immunopeptidome is a sampling of the cellular proteome and hence it contains information about the health state of cells. The peptide repertoire is influenced by intra- and extra-cellular perturbations - such as in the case of drug exposure, infection, or oncogenic transformation. Immunopeptidomics is the bioanalytical method by which the presented peptides are extracted from biological samples and analyzed by high-performance liquid chromatography coupled to tandem mass spectrometry (MS), resulting in a deep qualitative and quantitative snapshot of the immunopeptidome. In this review, we discuss published immunopeptidomics studies from recent years, grouped into three main domains: i) basic, ii) pre-clinical and iii) clinical research and applications. We review selected fundamental immunopeptidomics studies on the antigen processing and presentation machinery, on HLA restriction and studies that advanced our understanding of various diseases, and how exploration of the antigenic landscape allowed immune targeting at the pre-clinical stage, paving the way to pioneering exploratory clinical trials where immunopeptidomics is directly implemented in the conception of innovative treatments for cancer patients.

Comparative transcriptome analysis reveals the immune response of turbot (Scophthalmus maximus) induced by inactivated bivalent vaccine

Vibrio species are important pathogens that affect a wide range of farmed fish. Vaccination is regarded as the most efficacious strategy for fighting bacterial infections. However, the underlying mechanisms remain to be elucidated. In the present study, a comparative transcriptome analysis was performed on the spleens from turbot (Scophthalmus maximus) induced by an inactivated bivalent vaccine (Vibrio anguillarum and Vibrio harveyi, IVVah1) at 4 week and 1 day post further challenge. Strong immune responses were induced by the bivalent vaccine, besides differentially expressed genes (DEGs) associated with adaptive immunity, more innate immunity-related DEGs were detected. At the late stage of vaccination, immune-related molecules associated with pattern recognition receptors, inflammatory factors, complement and coagulation cascade-related components, and antigen processing and presentation were significantly regulated, and some of them were even further up-regulated after the bacterial challenge, indicating the cooperation of multiple immune processes during the vaccine immunization process. In addition to the terms or pathways associated with the immune response, enrichment analysis revealed multiple significantly enriched terms/pathways associated with the response to stimulus/stress, homeostasis, metabolism, and biosynthesis, suggesting that a defensive status was established by the bivalent vaccine. This study furnishes new insights into the internal mechanism of immunity upon a combined vaccine administrating in turbot and lays a foundation for developing highly immunogenic vaccines in teleost.

In Vivo and In Vitro Assay to Address Dendritic Cell Antigen Cross-Presenting Capacity

Antigen cross-presentation by dendritic cells is an important pathway to prime CD8⁺ T cells in infections, cancer, and other immune-mediated pathologies. Particularly in cancer, cross-presentation of tumor-associated antigens is crucial for an effective antitumor CTL response. The mostly accepted cross-presentation assay is to use chicken ovalbumin (OVA) as a model antigen and then utilize OVA-specific TCR transgenic CD8⁺ T (OT-I) cells to measure the cross-presenting capacity. Here we describe in vivo and in vitro assays to measure the function of antigen cross-presentation using cell-associated OVA.

scAllele: A versatile tool for the detection and analysis of variants in scRNA-seq

Single-cell RNA sequencing (scRNA-seq) data contain rich information at the gene, transcript, and nucleotide levels. Most analyses of scRNA-seq have focused on gene expression profiles, and it remains challenging to extract nucleotide variants and isoform-specific information. Here, we present scAllele, an integrative approach that detects single-nucleotide variants, insertions, deletions, and their allelic linkage with splicing patterns in scRNA-seq. We demonstrate that scAllele achieves better performance in identifying nucleotide variants than other commonly used tools. In addition, the read-specific variant calls by scAllele enables allele-specific splicing analysis, a unique feature not afforded by other methods. Applied to a lung cancer scRNA-seq dataset, scAllele identified variants with strong allelic linkage to alternative splicing, some of which are cancer specific and enriched in cancer-relevant pathways. scAllele represents a versatile tool to uncover multilayer information and previously unidentified biological insights from scRNA-seq data.

In Vitro and In Vivo Antigen Presentation and Diagnosis Development of Recombinant Overlapping Peptides Corresponding to Mtb ESAT-6/CFP-10

Cellular immunity in Mycobacteria tuberculosis (Mtb) infection is important for the pathogenesis and final clearance of intracellular Mtb infection. In addition, it is valuable for the diagnosis of tuberculosis. In this pioneering work, we tested in vitro and in vivo antigen presentation and diagnostic application of a recombinant overlapping peptide-protein derived from two Mtb RD1 antigens ESAT-6 and CFP-10 (ROP-TB). The overlapping peptide sequence of ROP-TB is cleaved by the cathepsin S enzyme and covers the entire length of the two proteins. ROP-TB can be expressed and purified from E. coli. Once taken in by antigen-presenting cells, ROP-TB can be cleaved into a peptide pool by cathepsin S within the cells. We found that in dendritic cells, ROP-TB can be processed in 6 hours of co-culture, while the ESAT-6/CFP-10 fusion protein remained in the endosomal compartment. In Mtb-infected mice, ROP-TB stimulated stronger specific T cell responses than pooled synthetic peptides derived from ESAT-6 and CFP-10. With regard to the presentation of in vivo antigens, in a guinea pig model infected with Mtb, ROP-TB induced delayed type hypersensitivity (DTH) responses comparable to those of the tuberculin purified protein derivative (PPD) and ESAT-6/CFP-10 fusion protein. In Mycobacterium bovis (Bovine TB)-infected cattle, ROP-TB elicited DTH responses. Finally, in Mtb infected patients, ROP-TB stimulated cellular immune responses in majority of patients (16/18) of different HLA phenotypes while a single peptide derived from the same proteins did not elicit the immune responses in all patients. In summary, in vitro and in vivo data suggest that ROP-TB stimulates a strong cellular immune response irrespective of HLA phenotypes and is therefore suitable for use in vitro and in vivo diagnostics.

The generation and application of antigen-specific T cell therapies for cancer and viral-associated disease

Immunotherapy with antigen-specific T cells is a promising, targeted therapeutic option for patients with cancer as well as for immunocompromised patients with virus infections. In this review, we characterize and compare current manufacturing protocols for the generation of T cells specific to viral and non-viral tumor-associated antigens. Specifically, we discuss: (1) the different methodologies to expand virus-specific T cell and non-viral tumor-associated antigen-specific T cell products, (2) an overview of the immunological principles involved when developing such manufacturing protocols, and (3) proposed standardized methodologies for the generation of polyclonal, polyfunctional antigen-specific T cells irrespective of donor source. Ex vivo expanded cells have been safely administered to treat numerous patients with virus-associated malignancies, hematologic malignancies, and solid tumors. Hence, we have performed a comprehensive review of the clinical trial results evaluating the safety, feasibility, and efficacy of these products in the clinic. In summary, this review seeks to provide new insights regarding antigen-specific T cell technology to benefit a rapidly expanding T cell therapy field.

Immunogenetic variation shapes the gut microbiome in a natural vertebrate population

BACKGROUND

The gut microbiome (GM) can influence many biological processes in the host, impacting its health and survival, but the GM can also be influenced by the host's traits. In vertebrates, Major Histocompatibility Complex (MHC) genes play a pivotal role in combatting pathogens and are thought to shape the host's GM. Despite this-and the documented importance of both GM and MHC variation to individual fitness-few studies have investigated the association between the GM and MHC in the wild.

RESULTS

We characterised MHC class I (MHC-I), MHC class II (MHC-II) and GM variation in individuals within a natural population of the Seychelles warbler (Acrocephalus sechellensis). We determined how the diversity and composition of the GM varied with MHC characteristics, in addition to environmental factors and other host traits. Our results show that the presence of specific MHC alleles, but not MHC diversity, influences both the diversity and composition of the GM in this population. MHC-I alleles, rather than MHC-II alleles, had the greatest impact on the GM. GM diversity was negatively associated with the presence of three MHC-I alleles (Ase-ua3, Ase-ua4, Ase-ua5), and one MHC-II allele (Ase-dab4), while changes in GM composition were associated with the presence of four different MHC-I alleles (Ase-ua1, Ase-ua7, Ase-ua10, Ase-ua11). There were no associations between GM diversity and TLR3 genotype, but GM diversity was positively correlated with genome-wide heterozygosity and varied with host age and field period.

CONCLUSIONS

These results suggest that components of the host's immune system play a role in shaping the GM of wild animals. Host genotype-specifically MHC-I and to a lesser degree MHC-II variation-can modulate the GM, although whether this occurs directly, or indirectly through effects on host health, is unclear. Importantly, if immune genes can regulate host health through modulation of the microbiome, then it is plausible that the microbiome could also influence selection on immune genes. As such, host-microbiome coevolution may play a role in maintaining functional immunogenetic variation within natural vertebrate populations. Video abstract.

Oral Vaccination With Recombinant Pichia pastoris Expressing Iridovirus Major Capsid Protein Elicits Protective Immunity in Largemouth Bass (Micropterus salmoides)

Largemouth bass iridovirus (LMBV) can cause high mortality and lead to heavy economic loss in the cultivation of largemouth bass, but there was no effective treatment. Here, the present study constructed a recombinant Pichia pastoris expressing LMBV major capsid protein (MCPD). The recombinant GS115-pW317-MCPD was then used to immunize largemouth bass via oral administration, and mucosal immune response mediated by immunoglobulins (Igs) was measured after oral immunization. Serum antibody levels were measured by ELISA, neutralizing antibody titers were determined by serum neutralization test (SNT), antigen presentation-related gene expressions were detected by RT-PCR, and the histopathological characteristics of immunized fish were assessed after challenging with 0.1 ml 107.19 TCID50/ml LMBV. The relative percentage survival (RPS) was also determined. Our results showed that the serum antibody titers of immunized fish were significantly higher than that of control groups (P < 0.05). IgT and IgM expressions in gut were increased significantly after vaccination with GS115-pW317-MCPD; however, much stronger response in gut was observed as compared with gill. The expression levels of major histocompatibility complex (MHC) II, CD8, and T-cell receptor (TCR) were significantly elevated in GS115-pW317-MCPD group (P < 0.05), while CD4 and MHC I transcription levels remained unchanged after oral immunization (P > 0.05). The RPS of fish orally immunized with 1.0 × 108 CFU/g GS115-pW317-MCPD was reached up to 41.6% after challenge with 0.1 ml 109.46 TCID50/ml LMBV. Moreover, orally immunizing with GS115-pW317-MCPD can relieve the pathological damage caused by LMBV. Therefore, GS115-pW317-MCPD showed a promising potential against LMBV.

Antigen presentation by MHC-E: a putative target for vaccination?

The essentially monomorphic human antigen presentation molecule HLA-E is an interesting candidate target to enable vaccination irrespective of genetic diversity. Predictive HLA-E peptide-binding motifs have been refined to facilitate HLA-E peptide discovery. HLA-E can accommodate structurally divergent peptides of both self and microbial origin. Intracellular processing and presentation pathways for peptides by HLA-E for T cell receptor (TCR) recognition remain to be elucidated. Recent studies show that, unlike canonical peptides, inhibition of the transporter associated with antigen presentation (TAP) is essential to allow HLA-E antigen presentation in cytomegalovirus (CMV) infection and possibly also of other non-canonical peptides. We propose three alternative and TAP-independent MHC-E antigen-presentation pathways, including for Mycobacterium tuberculosis infections. These insights may help in designing potential HLA-E targeting vaccines against tumors and pathogens.

Tissue Transglutaminase but Not Microbial Transglutaminase Is Inhibited by Exogenous Oxidative Substances in Celiac Disease

Enzymatic modification of gliadin peptides by human transglutaminase 2 (TG2) is a central step in celiac disease (CD) pathogenesis. Microbial transglutaminase (mTG) mimics the enzymatic function of TG2 and might play a role in CD. TG2 is inhibited by endogenous oxidative endoplasmic reticulum-resident protein 57 (ERp57), but data about mTG are lacking. We investigated the localization of ERp57 in duodenal biopsies and examined inhibition of TG2, and mTG by competitive, and oxidative molecules. Localization of ERp57 was investigated in duodenal biopsies from CD, and control patients by electron microcopy. Inhibition of TG2 and mTG was analyzed on an in vitro level using a photometric assay. ERp57 was observed within the lamina propria and its abundance within the endoplasmic reticulum (ER) was reduced in CD patients. TG2 was oxidatively inhibited by up to 95% by PX12 (p < 0.001) and L-cystine (p < 0.001), whereas mTG remained unaffected. The reduced presence of ERp57 within the ER of CD biopsies suggests a regulatory function of this protein within CD pathogenesis. PX12 and L-cystine oxidatively inhibit TG2 and might serve as treatment options in CD. mTG is poorly regulated and could contribute to the accumulation of immunogenic peptides within the gut with potential pathogenic effects.

Irg1/itaconate metabolic pathway is a crucial determinant of dendritic cells immune-priming function and contributes to resolute allergen-induced airway inflammation

Itaconate is produced from the mitochondrial TCA cycle enzyme aconitase decarboxylase (encoded by immune responsive gene1; Irg1) that exerts immunomodulatory function in myeloid cells. However, the role of the Irg1/itaconate pathway in dendritic cells (DC)-mediated airway inflammation and adaptive immunity to inhaled allergens, which are the primary antigen-presenting cells in allergic asthma, remains largely unknown. House dust mite (HDM)-challenged Irg1^-/- mice displayed increases in eosinophilic airway inflammation, mucous cell metaplasia, and Th2 cytokine production with a mechanism involving impaired mite antigen presentations by DC. Adoptive transfer of HDM-pulsed DC from Irg1-deficient mice into naïve WT mice induced a similar phenotype of elevated type 2 airway inflammation and allergic sensitization. Untargeted metabolite analysis of HDM-pulsed DC revealed itaconate as one of the most abundant polar metabolites that potentially suppress mitochondrial oxidative damage. Furthermore, the immunomodulatory effect of itaconate was translated in vivo, where intranasal administration of 4-octyl itaconate 4-OI following antigen priming attenuated the manifestations of HDM-induced airway disease and Th2 immune response. Taken together, these data demonstrated for the first time a direct regulatory role of the Irg1/itaconate pathway in DC for the development of type 2 airway inflammation and suggest a possible therapeutic target in modulating allergic asthma.

Strategy and clinical application of up-regulating cross presentation by DCs in anti-tumor therapy

The cross presentation of exogenous antigen (Ag) by dendritic cells (DCs) facilitates a diversified mode of T-cell activation, orchestrates specific humoral and cellular immunity, and contributes to an efficient anti-tumor immune response. DCs-mediated cross presentation is subject to both intrinsic and extrinsic factors, including the homing and phenotype of DCs, the spatiotemporal trafficking and degradation kinetics of Ag, and multiple microenvironmental clues, with many details largely unexplored. Here, we systemically review the current mechanistic understanding and regulation strategies of cross presentation by heterogeneous DC populations. We also provide insights into the future exploitation of DCs cross presentation for a better clinical efficacy in anti-tumor therapy.

Combining of transcriptomic and proteomic data to mine immune-related genes and proteins in the liver of Cynoglossus semilaevis challenged with Vibrio anguillarum

The liver is a multi-functional organ including metabolism, substance synthesis, detoxification, and various immune functions, and its role in immunity has attracted more and more attention. However, research on the liver immune response of fish infected by pathogenic bacteria is currently lacking. In this study, the transcriptomics and proteomics of the liver of Cynoglossus semilaevis infected with Vibrio anguillarum were analyzed. A total of 1470 genes and 497 proteins were differentially expressed in the pairwise comparison of obvious symptoms of infection (HOSG), no obvious symptoms of infection (NOSG) and PBS treatment (CG). Gene ontology and KEGG enrichment pathways analysis showed that differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were mainly enriched in toll-like receptors (TLRs), complement and coagulation cascades, nucleotide oligomerization domain (NOD)-like receptors (NLRs), mitogen-activated protein kinase (MAPK) and phagosome signaling pathways, which suggested the combined action of the five pathways were significant to enhance the liver immune defense. The combination of transcriptomic and proteomic analysis showed that ITGβ1, C3, C5 and MRC1 were significantly up-regulated, which might play an important role in the liver immune response to the recognition of V. anguillarum, inflammatory response and phagocytosis. The transcriptome and proteome data we obtained provide information on some key genes and proteins for further study of the mechanism of liver immune response.

Potent priming by inactivated whole influenza virus particle vaccines is linked to viral RNA uptake into antigen presenting cells

Current detergent or ether-disrupted split vaccines (SVs) for influenza do not always induce adequate immune responses, especially in young children. This contrasts with the whole virus particle vaccines (WPVs) originally used against influenza that were immunogenic in both adults and children but were replaced by SV in the 1970s due to concerns with reactogenicity. In this study, we re-evaluated the immunogenicity of WPV and SV, prepared from the same batch of purified influenza virus, in cynomolgus macaques and confirmed that WPV is superior to SV in priming potency. In addition, we compared the ability of WPV and SV to induce innate immune responses, including the maturation of dendritic cells (DCs) in vitro. WPV stimulated greater production of inflammatory cytokines and type-I interferon in immune cells from mice and macaques compared to SV. Since these innate responses are likely triggered by the activation of pattern recognition receptors (PRRs) by viral RNA, the quantity and quality of viral RNA in each vaccine were assessed. Although the quantity of viral RNA was similar in the two vaccines, the amount of viral RNA of a length that can be recognized by PRRs was over 100-fold greater in WPV than in SV. More importantly, 1000-fold more viral RNA was delivered to DCs by WPV than by SV when exposed to preparations containing the same amount of HA protein. Furthermore, WPV induced up-regulation of the DC maturation marker CD86 on murine DCs, while SV did not. The present results suggest that the activation of antigen-presenting DCs, by PRR-recognizable viral RNA contained in WPV is responsible for the effective priming potency of WPV observed in naïve mice and macaques. WPV is thus recommended as an alternative option for seasonal influenza vaccines, especially for children.

Modulation of lactate-lysosome axis in dendritic cells by clotrimazole potentiates antitumor immunity

BACKGROUND

Dendritic cells (DCs) play a critical role in antitumor immunity, but the therapeutic efficacy of DC-mediated cancer vaccine remains low, partly due to unsustainable DC function in tumor antigen presentation. Thus, identifying drugs that could enhance DC-based antitumor immunity and uncovering the underlying mechanism may provide new therapeutic options for cancer immunotherapy.

METHODS

In vitro antigen presentation assay was used for DC-modulating drug screening. The function of DC and T cells was measured by flow cytometry, ELISA, or qPCR. B16, MC38, CT26 tumor models and C57BL/6, Balb/c, nude, and Batf3-/- mice were used to analyze the in vivo therapy efficacy and impact on tumor immune microenvironment by clotrimazole treatment.

RESULTS

By screening a group of small molecule inhibitors and the US Food and Drug Administration (FDA)-approved drugs, we identified that clotrimazole, an antifungal drug, could promote DC-mediated antigen presentation and enhance T cell response. Mechanistically, clotrimazole acted on hexokinase 2 to regulate lactate metabolic production and enhanced the lysosome pathway and Chop expression in DCs subsequently induced DC maturation and T cell activation. Importantly, in vivo clotrimazole administration induced intratumor immune infiltration and inhibited tumor growth depending on both DCs and CD8+ T cells and potentiated the antitumor efficacy of anti-PD1 antibody.

CONCLUSIONS

Our findings showed that clotrimazole could trigger DC activation via the lactate-lysosome axis to promote antigen cross-presentation and could be used as a potential combination therapy approach to improving the therapeutic efficacy of anti-PD1 immunotherapy.

Molecular cloning, characterization and expression analysis of major histocompatibility complex class I alpha gene of pufferfish (Takifugu obscurus)

The major histocompatibility complex (MHC) genes play a key role in immune response in vertebrates. In this study, an MHC I alpha homolog gene (PfMHC Ⅰα) from pufferfish (Takifugu obscurus) was identified and its subcellular localization and expression patterns of PfMHC Ⅰα after challenge in vivo and in vitro were analysed. The open reading frame of PfMHC Ⅰα was 1,089 bp in length, encoding 362 aa. The immunofluorescence result revealed that PfMHC Ⅰα was presented on the membrane of lymphocytes. qRT-PCR analysis indicated that PfMHC Ⅰα was expressed in all examined tissues, with the highest expression in skin, followed by the expression in gills and whole blood. After challenge of Aeromonas hydrophila or polyinosinic: polycytidylic acid (Poly I:C) in vitro, the expression levels of PfMHC Ⅰα on pufferfish kidney lymphocytes were significantly up-regulated, with the highest expression level at 48 hr post-challenge. After infection with A. hydrophila or Poly I:C in vivo, the expression levels of PfMHC Ⅰα in the skin, whole blood and kidneys were significantly up-regulated. Taken together, it is speculated that PfMHC Ⅰα associates with resistance to both intracellular and extracellular antigens and plays an important role in the host response against pathogen infection in pufferfish.

Protein transduction domain-mediated influenza NP subunit vaccine generates a potent immune response and protection against influenza virus in mice

The nucleoprotein (NP) is a highly conserved internal protein of the influenza virus, a major target for universal influenza vaccine. Our previous studies have proven NP-based subunit vaccine can provide partial protection in mice. It is reported that the protein transduction domain (PTD) TAT protein from human immunodeficiency virus-1 (HIV-1) is able to penetrate cells when added exogenous protein and could effectively enhance the immune response induced by the exogenous protein. In present study, the recombinant protein TAT-NP, a fusion of TAT and NP was effectively expressed in Escherichia coli and purified as a candidate component for an influenza vaccine. We evaluated the immunogenicity and protective efficacy of recombinant influenza TAT-NP vaccine by intranasal immunization. In vitro experiments showed that TAT-NP could efficiently penetrate into cells. Animal results showed that mice vaccinated with TAT-NP could not only induce higher levels of IgG and mucosal IgA, but also elicit a robust cellular immune response. Moreover, the TAT-NP fusion protein could significantly increase the protection of mice against lethal doses of homologous influenza virus PR8 and could also provide mice protection against a lethal dose challenge against heterosubtypic H9N2 and H3N2 influenza virus. In conclusion, the recombinant TAT-NP might be a universal vaccine candidate against influenza virus.

A Vaccination with Boosted Cross Presentation by ER-Targeted Antigen Delivery for Anti-Tumor Immunotherapy

Vaccination is a widely-accepted resort against the invasion or proliferation of bacteria, parasites, viruses, and even cancer, which accounts heavily on an active involvement of CD8⁺ T cells. As one of the pivotal strategies taken by dendritic cells (DCs) to promote the responsiveness of CD8⁺ T cells to exogenous antigens, cross presentation culminates in an elevated overall host defense against cancer or infection. However, the precise mechanisms regulating such a process remains elusive, and current attempts to fuel cross presentation usually fail to exert efficiency. Here, model antigen OVA-loaded, endoplasmic reticulum (ER)-targeting cationic liposome (OVA@lipoT) is developed and characterized with a booster effect on the activation and maturation of DCs. Moreover, OVA@lipoT pulsed DCs exhibit overwhelming superiority in triggering cytotoxic T lymphocyte response both in vivo and in vitro. Data reveal that lipoT alters the intracellular trafficking and presenting pathway of antigen, which promotes cross presentation and bears close relationship to the ER-associated degradation (ERAD). These results may drop a hint about the interconnectivity between cross presentation and ER-targeted antigen delivery, provide extra information to the understanding of ERAD-mediated cross priming, and even shed new light on the design and optimization of vaccines against currently intractable cancers or virus-infection.

Effect of physicochemical properties on in vivo fate of nanoparticle-based cancer immunotherapies

Current advances of immunotherapy have greatly changed the way of cancer treatment. At the same time, a great number of nanoparticle-based cancer immunotherapies (NBCIs) have also been explored to elicit potent immune responses against tumors. However, few NBCIs are nearly in the clinical trial which is mainly ascribed to a lack understanding of in vivo fate of nanoparticles (NPs) for cancer immunotherapy. NPs for cancer immunotherapy mainly target the immune organs or immune cells to enable efficient antitumor immune responses. The physicochemical properties of NPs including size, shape, elasticity and surface properties directly affect their interaction with immune systems as well as their in vivo fate and therapeutic effect. Hence, systematic analysis of the physicochemical properties and their effect on in vivo fate is urgently needed. In this review, we first recapitulate the fundamentals for the in vivo fate of NBCIs including physio-anatomical features of lymphatic system and strategies to modulate immune responses. Moreover, we highlight the effect of physicochemical properties on their in vivo fate including lymph nodes (LNs) drainage, cellular uptake and intracellular transfer. Challenges and opportunities for rational design of NPs for cancer immunotherapy are also discussed in detail.

Cytosolic Delivery of Thiolated Neoantigen Nano-Vaccine Combined with Immune Checkpoint Blockade to Boost Anti-Cancer T Cell Immunity

Although tumor-specific neoantigen-based cancer vaccines hold tremendous potential, it still faces low cross-presentation associated with severe degradation via endocytosis pathway. Herein, a thiolated nano-vaccine allowing direct cytosolic delivery of neoantigen and Toll like receptor 9 agonist CpG-ODN is developed. This approach is capable of bypassing the endo-/lysosome degradation, increasing uptake and local concentration of neoantigen and CpG-ODN to activate antigen-presenting cells, significantly strengthening the anti-cancer T-cell immunity. In vivo immunization with thiolated nano-vaccine enhanced the lymph organ homing and promoted the antigen presentation on dendritic cells, effectively inhibited tumor growth, and significantly prolonged the survival of H22-bearing mice. Strikingly, further combination of the thiolated nano-vaccine with anti-programmed cell death protein-1 antibody (αPD-1) could efficiently reverse immunosuppression and enhance response rate of tumors, which led to enhanced tumor elimination, complete prevention of tumor re-challenge, and long-term survival above 150 d. Collectively, a versatile methodology to design cancer vaccines for strengthening anti-cancer T-cell immunity in solid tumors is presented, which could be further remarkably enhanced by combining with immune checkpoint inhibitors.

Innate Immune Response Against HIV-1

The innate immune system is comprised of both cellular and humoral players that recognise and eradicate invading pathogens. Therefore, the interplay between retroviruses and innate immunity has emerged as an important component of viral pathogenesis. HIV-1 infection in humans that results in hematologic abnormalities and immune suppression is well represented by changes in the CD4/CD8 T cell ratio and consequent cell death causing CD4 lymphopenia. The innate immune responses by mucosal barriers such as complement, DCs, macrophages, and NK cells as well as cytokine/chemokine profiles attain great importance in acute HIV-1 infection, and thus, prevent mucosal capture and transmission of HIV-1. Conversely, HIV-1 has evolved to overcome innate immune responses through RNA-mediated rapid mutations, pathogen-associated molecular patterns (PAMPs) modification, down-regulation of NK cell activity and complement receptors, resulting in increased secretion of inflammatory factors. Consequently, epithelial tissues lining up female reproductive tract express innate immune sensors including anti-microbial peptides responsible for forming primary barriers and have displayed an effective potent anti-HIV activity during phase I/II clinical trials.

Tumor-derived microparticles in tumor immunology and immunotherapy

Microvesicles or microparticles, a type of cytoplasm membrane-derived extracellular vesicles, can be released by cancer cells or normal cell types. Alteration of F-actin cytoskeleton by various signals may lead to the cytoplasm membrane encapsulating cellular contents to form microparticles, which contain various messenger molecules, including enzymes, RNAs and even DNA fragments, and are released to extracellular space. The release of microparticles by tumor cells (T-MPs) is a very common event in tumor microenvironments. As a result, T-MPs not only influence tumor cell biology but also profoundly forge tumor immunology. Moreover, T-MPs can act as a natural vehicle that delivers therapeutic drugs to tumor cells and immune cells, thus, remodeling tumor microenvironments and resetting antitumor immune responses, thus, conferring T-MPs a potential role in tumor immunotherapies and tumor vaccines. In this review, we focus on the double-edged sword role of T-MPs in tumor immunology, specifically in TAMs and DCs, and emphasize the application of drug-packaging T-MPs in cancer patients. We aim to provide a new angle to understand immuno-oncology and new strategies for cancer immunotherapy.

Engineering Strategies for Lymph Node Targeted Immune Activation

Development of vaccine technology that induces long lasting and potent adaptive immune responses is of vital importance to combat emerging pathogens and to design the next generation of cancer immunotherapies. Advanced biomaterials such as nanoparticle carriers are intensively explored to increase the efficacy and safety of vaccines and immunotherapies, based on their intrinsic potential to focus the therapeutic payload onto the relevant immune cells and to limit systemic distribution. With adaptive immune responses being primarily initiated in lymph nodes, the potency of nanoparticle vaccines in turn is tightly linked to their capacity to reach and accumulate in the lymph nodes draining the immunization site. Here, we discuss the main strategies applied to increase nanoparticle delivery to lymph nodes: (1) direct lymph node injection, (2) active cell-mediated transport through targeting of peripheral dendritic cells, and (3) exploiting passive transport through the afferent lymphatics.The intralymph nodal injection is obviously the most direct way for nanoparticles to reach lymph nodes, and multiple studies have demonstrated its capability in enhancing immunostimulant drugs' immune activation and increasing the therapeutic window. However, the requirement of using ultrasound guidance for mapping lymph nodes in patients renders intranodal administration unsuited for mass vaccination campaigns. As lymph nodes are fine structured organs with lymphocytes and chemokine gradients arrayed in a highly ordered fashion, the breakdown of such formats by the intralymph nodal injection is another concern. The exploitation of dendritic cells as live vectors for transporting nanoparticles to lymph nodes has intensively been studied both ex vivo and in vivo. While ex vivo engineering of dendritic cells in theory can achieve 100% dendritic cell-specific selectivity, a scenario impossible to be achieved in vivo, this procedure is usually laborious and complicated and entails the participation of professional staff and equipment. In addition, the poor efficiency of dendritic cell migration to the draining lymph node is another significant limitation following the injection of ex vivo cultured dendritic cells. Thus, in vivo targeting of surface receptors, particularly C-type lectin receptors, on dendritic cells by conjugating nanoparticles with antibodies or ligands is intensively studied by both academia and industry. Although such nanoparticles in vivo still face nonspecific engulfment by various phagocytes, multiple studies have shown its feasibility in targeting dendritic cells with high selectivity. Moreover, through optimizing the physicochemical properties of nanoparticles, nanoparticles can passively drain to lymph nodes carried by the interstitial flow. Compared to dendritic cell-mediated transport, passive draining is much faster and of higher efficiency. Of all such properties, size is the most important parameter as large particles (>500 nm) can only reach lymph nodes by an active cell-mediated transport. Other surface properties, such as the charge and the balance of hydrophobicity-vs-hydrophilicity, strongly influence the mobility of nanoparticles in the extracellular space. In addition, albumin, a natural fatty acid transporter, has recently been demonstrated capable of binding the amphiphiles through their lipid moiety and subsequent transporting them to lymph nodes.

ACOD1 in immunometabolism and disease

Immunometabolism plays a fundamental role in health and diseases and involves multiple genes and signals. Aconitate decarboxylase 1 (ACOD1; also known as IRG1) is emerging as a regulator of immunometabolism in inflammation and infection. Upregulation of ACOD1 expression occurs in activated immune cells (e.g., macrophages and monocytes) in response to pathogen infection (e.g., bacteria and viruses), pathogen-associated molecular pattern molecules (e.g., LPS), cytokines (e.g., TNF and IFNs), and damage-associated molecular patterns (e.g., monosodium urate). Mechanistically, several immune receptors (e.g., TLRs and IFNAR), adapter proteins (e.g., MYD88), ubiquitin ligases (e.g., A20), and transcription factors (e.g., NF-κB, IRFs, and STATs) form complex signal transduction networks to control ACOD1 expression in a context-dependent manner. Functionally, ACOD1 mediates itaconate production, oxidative stress, and antigen processing and plays dual roles in immunity and diseases. On the one hand, activation of the ACOD1 pathway may limit pathogen infection and promote embryo implantation. On the other hand, abnormal ACOD1 expression can lead to tumor progression, neurodegenerative disease, and immune paralysis. Further understanding of the function and regulation of ACOD1 is important for the application of ACOD1-based therapeutic strategies in disease.

Induction of adaptive immune responses against antigens incorporated within the capsid of simian virus 40

Simian virus 40 (SV40) is a monkey polyomavirus. The capsid structure is icosahedral and comprises VP1 units that measure 45 nm in diameter. Five SV40 VP1 molecules form one pentamer subunit, and a single icosahedral subunit comprises 72 pentamers; a single SV40 VP1 capsid comprises 360 SV40 VP1 molecules. In a previous study, we showed that an influenza A virus matrix protein 1 (M1) CTL epitope inserted within SV40 virus-like particles (VLPs) induced cytotoxic T lymphocytes (CTLs) without the need for an adjuvant. Here, to address whether SV40 VLPs induce adaptive immune responses against VLP-incorporated antigens, we prepared SV40 VLPs containing M1 or chicken ovalbumin (OVA). This was done by fusing M1 or OVA with the carboxyl terminus of SV40 VP2 and co-expressing them with SV40 VP1 in insect cells using a baculovirus vector. Intraperitoneal (i.p.) or intranasal administration of SV40 VLPs incorporating M1 induced the production of CTLs specific for the M1 epitope without the requirement for adjuvant. The production of antibodies against SV40 VLPs was also induced by i.p. administration of SV40 VLPs in the absence of adjuvant. Finally, the administration of SV40 VLPs incorporating OVA induced anti-OVA antibodies in the absence of adjuvant; in addition, the level of antibody production was comparable with that after i.p. administration of OVA plus alum adjuvant. These results suggest that the SV40 capsid incorporating foreign antigens can be used as a vaccine platform to induce adaptive immune responses without the need for adjuvant.

Recent Advances: The Imbalance of Immune Cells and Cytokines in the Pathogenesis of Hepatocellular Carcinoma

Recent advancement in the immunological understanding of genesis of hepatocellular carcinoma (HCC) has implicated a decline in anti-tumour immunity on the background of chronic inflammatory state of liver parenchyma. The development of HCC involves a network of immunological activity in the tumour microenvironment involving continuous interaction between tumour and stromal cells. The reduction in anti-tumour immunity is secondary to changes in various immune cells and cytokines, and the tumour microenvironment plays a critical role in modulating the process of liver fibrosis, hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), tumor invasion and metastasis. Thus, it is considered as one of primary factor behind the despicable tumour behavior and observed poor survival; along with increased risk of recurrence following treatment in HCC. The primary intent of the present review is to facilitate the understanding of the complex network of immunological interactions of various immune cells, cytokines and tumour cells associated with the development and progression of HCC.

Comparison of cattle BoLA-DRB3 typing by PCR-RFLP, direct sequencing, and high-resolution DNA melting curve analysis

Major histocompatibility complex (MHC) represents an important genetic marker for manipulation to improve the health and productivity of cattle. It is closely associated with numerous disease susceptibilities and immune responses. Bovine MHC, also called bovine leukocyte antigen (BoLA), is considered as a suitable marker for genetic diversity studies. In cattle, most of the polymorphisms are located in exon 2 of BoLA-DRB3, which encodes the peptide-binding cleft. In this study, the polymorphism of the BoLA-DRB3.2 gene in Holstein's calves was studied using high resolution melting curve analysis (HRM). Observed HRM results were compared to PCR-RFLP and direct sequencing techniques. Eight different HRM and seven different RFLP profiles were identified among the population studied. By comparing to sequencing data, HRM could completely discriminate all genotypes (eight profiles), while the RFLP failed to distinguish between the genotypes *1101/*1001 and *1104/*1501. According to the results, the HRM analysis method gave more accurate results than RFLP by differentiating between the BoLA-DRB3.2 genotypes. Due to the Co-dominant nature of the MHC alleles, HRM technique could be used for investigating the polymorphisms of genotypes and their associations with immune responses.

Integrated transcriptomic and proteomic analyses of grass carp intestines after vaccination with a double-targeted DNA vaccine of Vibrio mimicus

Intestinal mucosal immunity plays a vital role against Vibrio mimicus infection because it is an enteric pathogen causing serious vibriosis in fish. In the previous studies, we developed an oral double-targeted DNA vaccine of V. mimicus and demonstrated that the vaccine could elicit significantly higher intestinal mucosal immune response than did naked DNA vaccine. But, little is known underlying regulatory molecular mechanisms of the enhanced intestinal mucosal immunity. Here the transcriptome and proteome in the intestines of the grass carps immunized or not with the double-targeted DNA vaccine were investigated by using RNA-seq and iTRAQ-coupled LC-MS/MS. Compared with the control group, a total of 5339 differentially expressed genes (DEGs) and 1173 differentially expressed proteins (DEPs) were identified in the immunized fish intestines. Subsequently, the integrated analysis between transcriptome and proteome data revealed that 250 DEPs were matched with the corresponding DEGs (named associated DEPs/DEGs) at both transcriptome and proteome levels. Fifty of all the associated DEPs/DEGs were immune-related and mainly enriched in phagosome, antigen-processing and presentation, complement and coagulation cascades, NLRs and MAPK signaling pathways via Gene Ontology and KEGG pathway analyses, which suggested the coordination of the five activated pathways was essential to the enhanced intestinal mucosal immune response in the immunized fish. The protein-protein interaction analysis showed that 60 of the 63 immune-related DEPs to form an integrated network. Additionally, randomly selected DEGs and DEPs were respectively validated by quantitative real-time RT-PCR and multiple reaction monitoring (MRM) assay, indicating that the both RNA-Seq and iTRAQ results in the study were reliable. Overall, our comprehensive transcriptome and proteome data provide some key genes and their protein products for further research on the regulatory molecular mechanisms underlying the enhanced intestinal mucosal immunity.

Immunological Complexity of the Prostate Cancer Microenvironment Influences the Response to Immunotherapy

Prostate cancer is one of the most common cancers in men and a leading cause of cancer-related death. Recent advances in the treatment of advanced prostate cancer, including the use of more potent and selective inhibitors of the androgen signaling pathway, have provided significant clinical benefit for men with metastatic castration-resistant prostate cancer (mCRPC). However, most patients develop progressive lethal disease, highlighting the need for more effective treatments. One such approach is immunotherapy, which harness the power of the patient's immune system to identify and destroy cancer cells through the activation of cytotoxic CD8 T cells specific for tumor antigens. Although immunotherapy, particularly checkpoint blockade, can induce significant clinical responses in patients with solid tumors or hematological malignancies, minimal efficacy has been observed in men with mCRPC. In the current review, we discuss our current understanding of the immunological complexity of the immunosuppressive prostate cancer microenvironment, preclinical models of prostate cancer, and recent advances in immunotherapy clinical trials to improve outcomes for men with mCRPC.

Different types of adjuvants in prophylactic and therapeutic human papillomavirus vaccines in laboratory animals: a systematic review

Human papillomavirus (HPV) causes cervical carcinoma, which and is the third most common cancer, accounting for 275,000 deaths annually worldwide. Adjuvants have a key role in promotion of vaccine efficacy; therefore, using prophylactic and therapeutic vaccines combined with adjuvant could be of great benefit in prevention and treatment of cervical cancer. There are different types of adjuvants, including MF59^TM adjuvants, RNA-based, JY (interleukin2/chitosan), cholera toxin (CT), heat-labile enterotoxin (LT), Freund's adjuvant, alum, SA-4-1BBL, λ-carrageenan (λ-CGN), heat shock proteins (HSPs), juzen-taiho-to (JTT) and hochu-ekki-to (HET), ISCOM and ISCOMATRIX™, very small size proteoliposomes (VSSPs), granulocyte macrophage colony-stimulating factor (GM-CSF), and Toll-like receptors (TLRs). Adjuvants have various functions, especially in therapeutic vaccines, and they lead to an increase in cytotoxic T lymphocytes (CTLs), so they are important in the design of vaccines. Here, we review the currently used adjuvants and their combinations with HPV protein vaccines in order to introduce an appropriate adjuvant for HPV vaccines.

Major histocompatibility complex class I (MHC Iα) of Japanese flounder (Paralichthys olivaceus) plays a critical role in defense against intracellular pathogen infection

The major histocompatibility complex (MHC) is a highly polymorphic region of the vertebrate genome that plays a critical role in initiating immune responses towards invading pathogens. It is well known that MHC I molecules play a central role in the immune response to viruses. However, rare literatures were reported the role of MHC I in the resistance to intracellular bacteria. Sequences of MHC Iα were identified in multiple teleost species, including Japanese flounder (Paralichthys olivaceus), however, the immunological function of MHC Iα remain largely unknown. In this study, we examined the expression profile and biological activity of an MHC Iα homologue, PoMHC Iα, from P. olivaceus. Structural analysis showed that PoMHC Iα possesses conserved structural characteristics of MHC Iα proteins, including MHC_I domain, IGc1 domain, transmembrane region. Expression of PoMHC Iα was upregulated in a time-dependent manner by extracellular and intracellular bacterial pathogens and viral pathogen infection. Different expression patterns were exhibited in response to the infection of different types of microbial pathogens in different immune tissues. Recombinant PoMHC Iα increased the capability of host cells to defense against intracellular pathogen Edwardsiella tarda infection and enhanced the expression of immune related genes. The knockdown of PoMHC Iα attenuated the ability of cells to eliminate E. tarda, which was sustained by the in vivo results that overexpression of PoMHC Iα promoted the host defense against invading E. tarda. Antigen uptake assay indicated PoMHC Iα participated in cells antigen presentation. Collectively, this study is the first report that MHC Iα plays an important role in immune defense against intracellular bacterial pathogen in teleost. Taken together, these findings add new insights into the biological function of teleost MHC Iα and emphasize the importance of MHC I gene products for the control of E. tarda infection.

Peripheral blood mononuclear cell proteome profile in Behçet's syndrome

Behçet's syndrome (BS) is a systemic inflammatory disorder with unknown etiology. Investigation of proteome profiles of disease specific cells facilitates our understanding of the processes and related molecular pathways, especially in disorders like BS with complex inheritance pattern and clinical heterogeneity. In the current study, we evaluated the peripheral blood mononuclear cells (PBMCs) proteome of 59 patients with BS (33 in active and 26 in inactive phases) and of 28 healthy controls using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). Differentially expressed protein spots with at least twofold and/or statistically significant change (p ≤ 0.05) between active BS vs inactive BS, and also active BS vs healthy controls were identified by mass spectrometry (MALDI-TOF/TOF). Bioinformatic analyses revealed 16 differentially expressed proteins (12 of them in active vs inactive BS comparison, whereas 11 of them for active BS vs healthy control comparison) belonging to glycolysis, cytoskeleton organization, protein folding, and regulation of blood coagulation pathways. Stathmin (active BS vs inactive BS; fourfold, active BS vs healthy control; 4.7-fold) and WD repeat-containing protein-1 (active BS vs inactive BS; 2.7-fold, active BS vs healthy control; 2.7-fold), which are cytoskeleton-related proteins, were found to be lower in active patients compared to inactive patients and healthy control. Decreased levels of calreticulin (active BS vs inactive BS; 1.29-fold) and heat shock 70 kDa protein 8 (active BS vs healthy control; 1.5-fold) which are involved in protein folding and endoplasmic reticulum (ER) stress process, were observed in patients with active phase of BS. Down-regulation of protein folding and ER stress process proteins in BS patients may further support the involvement of ER stress in BS.

Thioesterase PPT1 balances viral resistance and efficient T cell crosspriming in dendritic cells

Crosspriming of CD8⁺ T cells by dendritic cells is crucial for host response against cancer and intracellular microbial infections. Ou et al. demonstrates that palmitoyl-protein thioesterase PPT1 is a phagosomal pH rheostat enabling both viral resistance and efficient crosspriming in cDC1s.

Conventional type 1 dendritic cells (cDC1s) are inherently resistant to many viruses but, paradoxically, possess fewer acidic phagosomes that enable antigen retention and cross-presentation. We report that palmitoyl-protein thioesterase 1 (PPT1), which catabolizes lipid-modified proteins in neurons, is highly expressed in cDC1s. PPT1-deficient DCs are more susceptible to vesicular stomatitis virus (VSV) infection, and mice with PPT1 deficiency in cDC1s show impaired response to VSV. Conversely, PPT1-deficient cDC1s enhance the priming of naive CD8⁺ T cells into tissue-resident KLRG1⁺ effectors and memory T cells, resulting in rapid clearance of tumors and Listeria monocytogenes. Mechanistically, PPT1 protects steady state DCs from viruses by promoting antigen degradation and endosomal acidification via V-ATPase recruitment. After DC activation, immediate down-regulation of PPT1 is likely to facilitate efficient cross-presentation, production of costimulatory molecules and inflammatory cytokines. Thus, PPT1 acts as a molecular rheostat that allows cDC1s to crossprime efficiently without compromising viral resistance. These results suggest potential therapeutics to enhance cDC1-dependent crosspriming.

Cross-Talk Between Antigen Presenting Cells and T Cells Impacts Intestinal Homeostasis, Bacterial Infections, and Tumorigenesis

Innate immunity is maintained in part by antigen presenting cells (APCs) including dendritic cells, macrophages, and B cells. APCs interact with T cells to link innate and adaptive immune responses. By displaying bacterial and tumorigenic antigens on their surface via major histocompatibility complexes, APCs can directly influence the differentiation of T cells. Likewise, T cell activation, differentiation, and effector functions are modulated by APCs utilizing multiple mechanisms. The objective of this review is to describe how APCs interact with and influence the activation of T cells to maintain innate immunity during exposure to microbial infection and malignant cells. How bacteria and cancer cells take advantage of some of these interactions for their own benefit will also be discussed. While this review will cover a broad range of topics, a general focus will be held around pathogens, cancers, and interactions that typically occur within the gastrointestinal tract.

Predicting Antigen Presentation-What Could We Learn From a Million Peptides?

Antigen presentation lies at the heart of immune recognition of infected or malignant cells. For this reason, important efforts have been made to predict which peptides are more likely to bind and be presented by the human leukocyte antigen (HLA) complex at the surface of cells. These predictions have become even more important with the advent of next-generation sequencing technologies that enable researchers and clinicians to rapidly determine the sequences of pathogens (and their multiple variants) or identify non-synonymous genetic alterations in cancer cells. Here, we review recent advances in predicting HLA binding and antigen presentation in human cells. We argue that the very large amount of high-quality mass spectrometry data of eluted (mainly self) HLA ligands generated in the last few years provides unprecedented opportunities to improve our ability to predict antigen presentation and learn new properties of HLA molecules, as demonstrated in many recent studies of naturally presented HLA-I ligands. Although major challenges still lie on the road toward the ultimate goal of predicting immunogenicity, these experimental and computational developments will facilitate screening of putative epitopes, which may eventually help decipher the rules governing T cell recognition.

Tannic Acid-Modified Silver and Gold Nanoparticles as Novel Stimulators of Dendritic Cells Activation

Silver nanoparticles (AgNPs) are promising new antimicrobial agents against a wide range of skin and mucosal pathogens. However, their interaction with the immune system is currently not fully understood. Dendritic cells (DCs) are crucial during development of T cell-specific responses against bacterial and viral pathogens. We have previously shown that tannic acid-modified silver nanoparticles (TA-AgNPs) consist of a promising microbicide against HSV-2. The aim of this study was to compare the ability of TA-AgNPs or TA-AuNPs of similar sizes (TA-Ag/AuNPs) to induce DCs maturation and activation in the presence of HSV-2 antigens when used at non-toxic doses. First, we used JAWS II DC line to test toxicity, ultrastructure as well as activation markers (MHC I and II, CD40, CD80, CD86, PD-L1) and cytokine production in the presence of TA-Ag/AuNPs. Preparations of HSV-2 treated with nanoparticles (TA-Ag/AuNPs-HSV-2) were further used to investigate HSV-2 antigen uptake, activation markers, TLR9 expression, and cytokine production. Additionally, we accessed proliferation and activation of HSV-2-specific T cells by DCs treated with TA-AgNP/AuNPs-HSV-2. We found that both TA-AgNPs and TA-AuNPs were efficiently internalized by DCs and induced activated ultrastructure. Although TA-AgNPs were more toxic than TA-AuNPs in corresponding sizes, they were also more potent stimulators of DCs maturation and TLR9 expression. TA-Ag/AuNPs-HSV-2 helped to overcome inhibition of DCs maturation by live or inactivated virus through up-regulation of MHC II and CD86 and down-regulation of CD80 expression. Down-regulation of CD40 expression in HSV-2-infected DCs was reversed when HSV-2 was treated with TA-NPs sized >30 nm. On the other hand, small-sized TA-AgNPs helped to better internalize HSV-2 antigens. HSV-2 treated with both types of NPs stimulated activation of JAWS II and memory CD8+ T cells, while TA-AgNPs treatment induced IFN-γ producing CD4+ and CD8+ T cells. Our study shows that TA-AgNPs or TA-AuNPs are good activators of DCs, albeit their final effect upon maturation and activation may be metal and size dependent. We conclude that TA-Ag/AuNPs consist of a novel class of nano-adjuvants, which can help to overcome virus-induced suppression of DCs activation.

Targeting the Leukemia Antigen PR1 with Immunotherapy for the Treatment of Multiple Myeloma

Purpose: PR1 is a human leukocyte antigen (HLA)-A2 nonameric peptide derived from neutrophil elastase (NE) and proteinase 3 (P3). We have previously shown that PR1 is cross-presented by solid tumors, leukemia, and antigen-presenting cells, including B cells. We have also shown that cross-presentation of PR1 by solid tumors renders them susceptible to killing by PR1-targeting immunotherapies. As multiple myeloma is derived from B cells, we investigated whether multiple myeloma is also capable of PR1 cross-presentation and subsequently capable of being targeted by using PR1 immunotherapies.Experimental Design: We tested whether multiple myeloma is capable of cross-presenting PR1 and subsequently becomes susceptible to PR1-targeting immunotherapies, using multiple myeloma cell lines, a xenograft mouse model, and primary multiple myeloma patient samples.Results: Here we show that multiple myeloma cells lack endogenous NE and P3, are able to take up exogenous NE and P3, and cross-present PR1 on HLA-A2. Cross-presentation by multiple myeloma utilizes the conventional antigen processing machinery, including the proteasome and Golgi, and is not affected by immunomodulating drugs (IMiD). Following PR1 cross-presentation, we are able to target multiple myeloma with PR1-CTL and anti-PR1/HLA-A2 antibody both in vitro and in vivoConclusions: Collectively, our data demonstrate that PR1 is a novel tumor-associated antigen target in multiple myeloma and that multiple myeloma is susceptible to immunotherapies that target cross-presented antigens. Clin Cancer Res; 24(14); 3386-96. ©2018 AACR.

Essential PTX3 Biology (not only) for Cardiologists and Cardiac Surgeons

Inflammation has been recognized to form an integral part of the atherosclerotic process. Much consideration has been given lately to the role played in atherogenesis by C-reactive protein (CRP). Although not accepted unequivocally, CRP appears to be not only a marker, but also an active mediator of the atherosclerotic process. Pentraxin 3 (PTX3) is a newly identified acute phase reactant which shares some structural and some functional properties with CRP. On the other hand, pentraxin 3 displays unique biological properties of its own, including a possible role in the pathogenesis of cardiovascular diseases and in processes accompanying the natural evolution of surgical wounds. This review article discusses recent information concerning basic pentraxin 3 biology in inflammation and in innate immunity reactions as viewed by a cardiologist in the context of acute coronary events and by a surgeon in patients struck with multiple wounds who are at the same time menaced by bacterial infections.