An IL-17F/A heterodimer protein is produced by mouse Th17 cells and induces airway neutrophil recruitment

Evolutionary insights and poly(I:C)-induced changes in expression and m6A modifications of il17ra and il17rc in Miichthysmiiuy

Interleukin-17 receptor A (IL17RA) and IL17RC form a receptor complex critical for initiating IL-17A-mediated immune responses, a hallmark of T helper 17 (Th17) cells. In this study, il17ra and il17rc were identified in miiuy croaker (Miichthys miiuy) and bioinformatics analysis revealed their evolutionary and structural conservation, underscoring their roles in immunity. However, there has been little research on the IL-17 receptor family from the perspective of N6-methyladenosine (m6A) modifications. Using methylated RNA immunoprecipitation sequencing (MeRIP-seq), we identified strong m6A modifications on the last exons of il17ra and il17rc, validated by MeRIP-PCR. Poly(I:C) stimulation significantly upregulated il17ra and il17rc expression, while reducing their m6A modification levels, implicating these changes in antiviral immunity. Interestingly, cycloleucine (CL), a well-known methylation inhibitor, did not alter the expression of il17ra and il17rc but promoted the nuclear-to-cytoplasmic transport of il17ra mRNA, potentially influencing its translation process. These findings provide valuable insights into the regulatory roles of m6A modifications in il17ra and il17rc function and highlight their importance in the antiviral immune response.

Low-frequency ultrasound alleviates pulmonary inflammation induced by Klebsiella pneumoniae in mice by inhibiting the TNFR1/NF-κB pathway

BACKGROUND

Therapeutic ultrasound has been found to promote tissue healing and reduce inflammation in non-infectious diseases, but its efficacy in infectious inflammation remains unclear. Here, we employ the mice pneumonia model to explore the anti-inflammatory effects of low-frequency ultrasound (LFU) and elucidate its potential molecular mechanisms.

METHODS

Pneumonia in mice was induced by intratracheal instillation of 100 μL of a 4.5 × 108 CFU/mL Klebsiella pneumoniae (Kp) bacterial suspension. A single LFU treatment (29.36 kHz, 270 mW/cm2, 10 min) was applied to the chest of mice at 6 or 48 h after infection. Biological samples were collected for gene, protein, and cellular experiments.

RESULTS

LFU demonstrated good anti-inflammatory effects in mice during the recovery phase of Kp infection (48 h after infection). Although LFU alone had no bactericidal effects, it slightly reduced the pathological score of lung injury and significantly decreased the infiltration of CD45+ leukocytes. Additionally, the protein levels of TNF-α, GM-CSF and COX-2 in the bronchoalveolar lavage fluid were significantly reduced. Bulk RNA-sequencing results showed that the TNF receptor (TNFR)/NF-κB pathway was up-regulated after Kp infection, which was suppressed after LFU treatment. Western blot and immunofluorescence revealed LFU significantly reduced the protein levels of TNFR1, p-p65, and nuclear p65. The anti-inflammatory effect of LFU was comparable to a 20 mg/kg NF-κB inhibitor and superior to a 15 mg/kg TNFR antagonist.

CONCLUSION

LFU exerts anti-inflammatory effects by inhibiting the TNFR1/NF-κB pathway during the recovery period of Kp infection, reducing inflammatory transcription and thereby decreasing the release of inflammatory factors.

Small molecule interleukin (IL) 17A/A antagonists and antibodies blocking both IL17A/A and IL17A/F demonstrate equivalent degrees of efficacy in preclinical models of skin and joint inflammation

T-helper 17 (Th17) cells produce homodimeric IL17A/A and IL17F/F cytokines as well as the heterodimeric IL17A/F isoform, all having well known roles in defense against extracellular pathogens including fungal infection. Antibodies targeting IL17A (such as secukinumab and ixekizumab) have been approved to treat psoriasis, psoriatic arthritis, ankylosing spondylitis, and axial spondyloarthritis and are under further investigation as therapies in inflammatory disorders such as hidradenitis suppurativa and giant cell arteritis. Because many patients dislike injections with needles, orally bioavailable small molecule IL17 antagonists are desirable as next-generation drugs as long as they can replicate the degree of efficacy observed with anti-IL17A biologics. We recently described novel small molecules binding as 2 copies to the IL17A/A homodimer with only weak effects on the IL17A/F heterodimer. Because approved antibodies binding IL17A neutralize both IL17A/A and IL17A/F, we assessed whether targeting IL17A/A would be sufficient to bring efficacy comparable to IL17A biologics. In comparison to IL17A/F and IL17F/F, we found that the IL17A/A homodimer is the strongest initiator of signaling and that comparable IL17A/A to IL17A/F ratios are expressed in Th17 cells and in human psoriatic skin tissue. Furthermore, our IL17A/A-specific small molecules block the effects of Th17 cell supernatants on keratinocytes to similar maximal responses as anti-IL17A. Our IL17A/A-selective antagonists deliver comparable efficacy to anti-IL17A biologics in several rodent inflammatory models of psoriasiform dermatitis and arthritis. These results support neutralizing IL17A/A with oral small molecule antagonists is an attractive approach to provide differentiated, next-generation therapies for inflammatory disorders. SIGNIFICANCE STATEMENT: This study found that orally active small molecule antagonists of the proinflammatory cytokine IL17A that preferentially bind the IL17A/A form produced equivalent efficacy to monoclonal antibodies that can neutralize both IL17A/A and IL17A/F. This indicates that the IL17A/A homodimer is the dominant isoform driving inflammation in diseases such as psoriasis and that oral inhibitors targeting IL17A/A may be useful next-generation IL17 therapeutics.

Titanium implants trigger extra-periodontal T cell-mediated immunity

Peri-implant inflammation and periodontitis share a common etiology rooted in periodontopathic bacterial invasion, with periodontitis notably linked to systemic inflammatory comorbidities involving T cells. However, the intricate processes within the peri-implant microenvironment and systemic repercussions of implants, particularly related to implant materials, remain inadequately understood. We aim to elucidate the impact of contact with titanium materials, widely employed in dental implants for their high biocompatibility and excellent corrosion resistance, on diverse T cell subpopulations. This study adopts a comprehensive approach, encompassing (1) transcriptomic profiling of peri-implant epithelium in a rat model, (2) examination of phenotypic and functional changes in T cell immunity in human blood cells cultured on titanium discs, and (3) in vivo validation of T cells in implanted mice. Transcriptomic evidence and functional in vitro results revealed that exposure to titanium materials promoted T cell activation and differentiation towards inflammatory subsets, and escalated the secretion of corresponding cytokines. In vivo results showed that most of the gingiva-extracted T cells were activated in both healthy and implanted mice, the latter exhibiting significant lymphadenitis. High-dimensional flow cytometric findings in the in vivo lymphadenitis model indicated titanium-induced T cell immunity, involving preferential activation of Th1, Th17, and Tc1 cells over Tregs in adjacent lymph nodes within three days after implant placement. These findings highlight the pivotal role of T cells in the initiation of peri-implant inflammation, emphasizing the need to understand extra-periodontal inflammatory complications associated with implant surgeries. Our study provides a foundation for future therapeutic strategies targeting T cell responses to enhance the success and longevity of dental implant treatments.

Leveraging Evolutionary Immunology in Interleukin-6 and Interleukin-17 Signaling for Lung Cancer Therapeutics

Lung cancer is among the most common instances of cancer subtypes and is associated with high mortality rates. Due to the availability of fewer therapies and delayed clinical investigations, the number of cancer incidences is rising dramatically. This is possibly an effect of immune modulations and chemotherapeutic drugs that raises cancer resistance. Among the list, IL-6 and IL-17 are host-derived paradoxical effectors that attune immune responses in malignant lung cells. Their excessive release in the cytokine milieu stabilizes immunosuppressive phenotypes, resulting in cellular perturbations. During tumor development, the significance of these molecules is reflected in their potential to regulate oncogenesis by initiating a myriad of signaling events that influence tumor growth and the metastatic ability of benign cancer cells. Moreover, their transactivation contributes to antiapoptotic mechanisms and favors cancer cell survival via constitutive expression of immunoregulatory molecules. Co-evolution and gene duplication events could be the major drivers behind cytokine evolution, which have prompted generic changes and, hence, the additive effect. The evolutionary model and statistical analysis provide evidence about the cytokines ancestral relationships and site-specific conservation, which is more convincing as both cytokines share cysteine-knot-like structures important in maintaining structural integrity. Funneling through the findings could help find residues that serve a catalytic role in immune functioning. Designing peptides or subunit vaccine formulations against those conserved residues could aid in combating lung cancer pathogenesis.

Targeting IL-17 and its receptors: A feasible way for natural herbal medicines to modulate fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by processive synovial hyperplasia and abnormal proliferation of fibroblast-like synoviocytes (FLSs), and can eventually lead to progressive joint destruction. Increasing evidence has demonstrated that cytokines play pivotal roles in the pathogenesis of RA. In particular, the production of interleukin (IL)-17 by T helper 17 (Th17) cells is closely associated with the development of RA, and inhibition of IL-17/IL-17R could regulate the production of inflammatory factors by FLSs, which may be a feasible way to reduce inflammation and bone destruction in RA. Currently, accumulating evidence suggests that the utilization of natural herbal medicines is advantageous in the management of RA. In our present paper, a comprehensive reference search was conducted of the classic Materia Medica books, literature, online databases, academic search engines, and MS. or Ph. D theses. In conclusion, natural herbal medicines with antirheumatic activities that modulate FLSs by targeting IL-17/IL-17R were summarized. Furthermore, we also discuss the limitations and potential research directions for the future development of natural herbal medicines as candidate drugs for RA management in the clinic.

The immune responses elicited by six recombinant antigens of Mycoplasma hyopneumoniae in mice

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causative agent of swine enzootic pneumonia, resulting in substantial economic losses in global pig farming. Although vaccination is the primary strategy for controlling M. hyopneumoniae infection, current vaccines fall short in preventing transmission of this pathogen or protecting the body from secondary infection. This study aimed to assess the immunogenicity of six recombinant antigens (P97R1, P46, GAPDH, PdhA, DnaK, and EF-Tu) of M. hyopneumoniae through intramuscular immunization in mice. The results showed that the six antigens elicited high levels of serum IgG. Among them, P97R1, P46, PdhA, and DnaK stimulated robust antigen-specific IgA mucosal immune responses. CCK-8 assays revealed that both P97R1 and DnaK significantly increased the proliferation of mononuclear cells from spleen and lung, and DnaK also promoted the proliferation of blood mononuclear cells. Additionally, PdhA induced Th17-type immune response with a high level of IL-17 level in serum. Flow cytometry analysis indicated that P97R1 and PdhA increased the ratio of CD8+/CD4+ T lymphocyte, favoring cytotoxic T lymphocyte (CTL) immune responses. Notably, P97R1 immunization significantly decreased the percentages of CD4+ T cells while increased the percentages of CD8+ T cells. The present findings demonstrate that the candidate antigens P97R1, PdhA, and DnaK of M. hyopneumoniae induce specific humoral and mucosal immunity; P97R1 and DnaK also stimulated intense cellular immunity, and PdhA induced CTL and Th17-type immune responses. In conclusion, P97R1, PdhA, and DnaK emerge as potential candidate antigens for the future development of a more effective subunit vaccine against M. hyopneumoniae.

Mesenchymal stem cell application in pulmonary disease treatment with emphasis on their interaction with lung-resident immune cells

Due to the vital importance of the lungs, lung-related diseases and their control are very important. Severe inflammatory responses mediated by immune cells were among the leading causes of lung tissue pathology and damage during the COVID-19 pandemic. In addition, uncontrolled immune cell responses can lead to lung tissue damage in other infectious and non-infectious diseases. It is essential to control immune responses in a way that leads to homeostasis. Immunosuppressive drugs only suppress inflammatory responses and do not affect the homeostasis of reactions. The therapeutic application of mesenchymal stem cells (MSCs), in addition to restoring immune homeostasis, can promote the regeneration of lung tissue through the production of growth factors and differentiation into lung-related cells. However, the communication between MSCs and immune cells after treatment of pulmonary diseases is essential, and investigating this can help develop a clinical perspective. Different studies in the clinical phase showed that MSCs can reverse fibrosis, increase regeneration, promote airway remodeling, and reduce damage to lung tissue. The proliferation and differentiation potential of MSCs is one of the mechanisms of their therapeutic effects. Furthermore, they can secrete exosomes that affect the function of lung cells and immune cells and change their function. Another important mechanism is that MSCs reduce harmful inflammatory responses through communication with innate and adaptive immune cells, which leads to a shift of the immune system toward regulatory and hemostatic responses.

Shedding reduction and immunity modulation in piglets with an inactivated Mycoplasma hyopneumoniae vaccine encapsulated in nanostructured SBA-15 silica

Mycoplasma (M.) hyopneumoniae is a primary etiological agent of porcine enzootic pneumonia (PEP), a disease that causes significant economic losses to pig farming worldwide. Current commercial M. hyopneumoniae vaccines induce partial protection, decline in preventing transmission of this pathogen or inducing complete immunity, evidencing the need for improving vaccines against PEP. In our study, we aimed to test the effectiveness of the SBA-15 ordered mesoporous silica nanostructured particles as an immune adjuvant of a vaccine composed of M. hyopneumoniae strain 232 proteins encapsulated in SBA-15 and administered by intramuscular route in piglets to evaluate the immune responses and immune-protection against challenge. Forty-eight 24-day-old M. hyopneumoniae-free piglets were divided into four experimental groups with different protocols, encompassing a commercial vaccine against M. hyopneumoniae, SBA-15 vaccine, SBA-15 adjuvant without antigens and a non-immunized group. All piglets were challenged with the virulent strain 232 of M. hyopneumoniae. Piglets that received the SBA-15 and commercial vaccine presented marked immune responses characterized by anti-M. hyopneumoniae IgA and IgG antibodies in serum, anti-M. hyopneumoniae IgA antibodies in nasal mucosa and showed an upregulation of IL-17 and IL-4 cytokines and downregulation of IFN-γ in lungs 35 days post-infection. Piglets immunized with SBA-15 vaccine presented a reduction of bacterial shedding compared to piglets immunized with a commercial bacterin. In addition, piglets from SBA-15 adjuvant suspension group presented increased IL-17 gene expression in the lungs without involvement of Th1 and Th2 responses after challenge. These results indicated that SBA-15 vaccine induced both humoral and cell-mediated responses in the upper respiratory tract and lungs, first site of replication and provided protection against M. hyopneumoniae infection with a homologous strain with reduction of lung lesions and bacterial shedding. Finally, these results enhance the potential use of new technologies such as nanostructured particles applied in vaccines for the pig farming industry.

Inhibition of phosphoinositide 3-kinase activity attenuates neutrophilic airway inflammation and inhibits pyrin domain-containing 3 inflammasome activation in an ovalbumin-lipopolysaccharide-induced asthma murine model

BACKGROUND

Existing investigations suggest that the blockade of phosphoinositide 3-kinase (PI3K) activity contributes to inflammatory solution in allergic asthma, but whether this inhibition directly attenuates neutrophilic airway inflammation in vivo is still unclear. We explored the pharmacological effects of LY294002, a specific inhibitor of PI3K on the progression of neutrophilic airway inflammation and investigated the underlying mechanism.

METHODS AND RESULTS

Female C57BL/6 mice were intranasally sensitized with ovalbumin (OVA) together with lipopolysaccharide (LPS) on days 0 and 6, and challenged with OVA on days 14-17 to establish a neutrophilic airway disease model. In the challenge phase, a subset of mice was treated intratracheally with LY294002. We found that treatment of LY294002 attenuates clinic symptoms of inflammatory mice. Histological studies showed that LY294002 significantly inhibited inflammatory cell infiltration and mucus production. The treatment also significantly inhibited OVA-LPS induced increases in inflammatory cell counts, especially neutrophil counts, and IL-17 levels in bronchoalveolar lavage fluid (BALF). LY294002 treated mice exhibited significantly increased IL-10 levels in BALF compared to the untreated mice. In addition, LY294002 reduced the plasma concentrations of IL-6 and IL-17. The anti-inflammatory effects of LY29402 were correlated with the downregulation of NLRP3 inflammasome.

CONCLUSIONS

Our findings suggested that LY294002 as a potential pharmacological target for neutrophilic airway inflammation.

Interleukin-2/anti-interleukin-2 complex attenuates inflammation in a mouse COPD model by expanding CD4+ CD25+ Foxp3+ regulatory T cells

BACKGROUND AND PURPOSE

Chronic, nonspecific inflammation of the alveoli and airways is an important pathological feature of chronic obstructive pulmonary disease (COPD), while sustained inflammatory reactions can cause alveolar damage. Regulatory T cells (Tregs) inhibit inflammation, whereas the interleukin-2/anti-interleukin-2 complex (IL-2C) increases the number of Tregs; however, whether the IL-2C has a therapeutic role in COPD remains unknown. Therefore, this study investigated whether IL-2C alleviates lung inflammation in COPD by increasing the number of Tregs.

EXPERIMENTAL APPROACH

A mouse COPD model was created by exposing mice to lipopolysaccharides (LPS) and cigarette smoke (CS), and the effects of IL-2C treatment on COPD were evaluated. The number of Tregs in the spleen and lung, pulmonary pathological changes, and inflammatory damage were examined through flow cytometry, histopathology, and immunofluorescence, respectively.

KEY RESULTS

IL-2C increased the number of Treg cells in the spleen and lungs after exposure to CS and LPS, reduced the number of T helper 17 (Th17) cells in lung tissue, and improved the Th17/Treg balance. IL-2C decreased the number of inflammatory cells and reduced the levels of pro-inflammatory cytokines IL-6, TNF-α, IL-1β, CCL5, KC, and MCP-1 in bronchoalveolar lavage fluid and serum. IL-2C significantly reduced the pathological scores for lung inflammation, as well as decreased airway mucus secretion and infiltration of neutrophils and macrophages in the lungs. The depletion of Tregs using anti-CD25 antibodies eliminated the beneficial effects of IL-2C.

CONCLUSIONS AND IMPLICATIONS

IL-2C is a potential therapeutic agent for alleviating excessive inflammation in the lungs of patients with COPD.

Gut epithelial Interleukin-17 receptor A signaling can modulate distant tumors growth through microbial regulation

Microbes influence cancer initiation, progression and therapy responsiveness. IL-17 signaling contributes to gut barrier immunity by regulating microbes but also drives tumor growth. A knowledge gap remains regarding the influence of enteric IL-17-IL-17RA signaling and their microbial regulation on the behavior of distant tumors. We demonstrate that gut dysbiosis induced by systemic or gut epithelial deletion of IL-17RA induces growth of pancreatic and brain tumors due to excessive development of Th17, primary source of IL-17 in human and mouse pancreatic ductal adenocarcinoma, as well as B cells that circulate to distant tumors. Microbial dependent IL-17 signaling increases DUOX2 signaling in tumor cells. Inefficacy of pharmacological inhibition of IL-17RA is overcome with targeted microbial ablation that blocks the compensatory loop. These findings demonstrate the complexities of IL-17-IL-17RA signaling in different compartments and the relevance for accounting for its homeostatic host defense function during cancer therapy.

A novel "prime and pull" strategy mediated by the combination of two dendritic cell-targeting designs induced protective lung tissue-resident memory T cells against H1N1 influenza virus challenge

Vaccination is still the most promising strategy for combating influenza virus pandemics. However, the highly variable characteristics of influenza virus make it difficult to develop antibody-based universal vaccines, until now. Lung tissue-resident memory T cells (TRM), which actively survey tissues for signs of infection and react rapidly to eliminate infected cells without the need for a systemic immune reaction, have recently drawn increasing attention towards the development of a universal influenza vaccine. We previously designed a sequential immunization strategy based on orally administered Salmonella vectored vaccine candidates. To further improve our vaccine design, in this study, we used two different dendritic cell (DC)-targeting strategies, including a single chain variable fragment (scFv) targeting the surface marker DC-CD11c and DC targeting peptide 3 (DCpep3). Oral immunization with Salmonella harboring plasmid pYL230 (S230), which displayed scFv-CD11c on the bacterial surface, induced dramatic production of spleen effector memory T cells (TEM). On the other hand, intranasal boost immunization using purified DCpep3-decorated 3M2e-ferritin nanoparticles in mice orally immunized twice with S230 (S230inDC) significantly stimulated the differentiation of lung CD11b+ DCs, increased intracellular IL-17 production in lung CD4+ T cells and elevated chemokine production in lung sections, such as CXCL13 and CXCL15, as determined by RNAseq and qRT‒PCR assays, resulting in significantly increased percentages of lung TRMs, which could provide efficient protection against influenza virus challenge. The dual DC targeting strategy, together with the sequential immunization approach described in this study, provides us with a novel "prime and pull" strategy for addressing the production of protective TRM cells in vaccine design.

Interactions between neutrophils and T-helper 17 cells

Neutrophils comprise the majority of immune cells in human peripheral circulation, have potent antimicrobial activities, and are clinically significant in their abundance, heterogeneity, and subcellular localization. In the past few years, the role of neutrophils as components of the innate immune response has been studied in numerous ways, and these cells are crucial in fighting infections, autoimmune diseases, and cancer. T-helper 17 (Th17) cells that produce interleukin 17 (IL-17) are critical in fighting infections and maintaining mucosal immune homeostasis, whereas they mediate several autoimmune diseases. Neutrophils affect adaptive immune responses by interacting with adaptive immune cells. In this review, we describe the physiological roles of both Th17 cells and neutrophils and their interactions and briefly describe the pathological processes in which these two cell types participate. We provide a summary of relevant drugs targeting IL-17A and their clinical trials. Here, we highlight the interactions between Th17 cells and neutrophils in diverse pathophysiological situations.

Differential regulation of IL-17A and IL-17F via STAT5 contributes to psoriatic disease

BACKGROUND

IL-17A plays a pivotal pathogenic role in several immune-mediated inflammatory diseases. Despite sharing 50% sequence homology with IL-17A, the role of IL-17F remains less clear. Clinical findings suggest that dual inhibition of IL-17A and IL-17F in psoriatic disease is more efficacious than IL-17A inhibition alone, positing a pathogenic role for IL-17F.

OBJECTIVE

We characterized the regulation of IL-17A and IL-17F in psoriatic disease.

METHODS

Using both in vitro systems and lesional skin tissue from patients, we interrogated the chromosomal, transcriptional, and protein expression landscape of IL-17A+ and IL-17F+ TH17 cells. Alongside established assays such as single-cell RNA sequencing, we developed a novel cytokine-capture technique that was combined with chromatin immunoprecipitation sequencing and RNA sequencing.

RESULTS

We confirm a preferential elevation of IL-17F over IL-17A in psoriatic disease and show that expression of each isoform predominantly occurs in distinct cell populations. The expression of both IL-17A and IL-17F exhibited a high degree of plasticity, with the balance between the 2 isoforms influenced by proinflammatory signaling and by anti-inflammatory drugs such as methylprednisolone. This plasticity was reflected in a broad H3K4me3 region at the IL17A-F locus, while opposing effects of STAT5/IL-2 signaling were observed for each of the 2 genes. Functionally, higher IL17F expression was linked to greater cell proliferation.

CONCLUSION

There are key differences in the regulation of IL-17A and IL-17F in psoriatic disease, leading to distinct inflammatory cell populations. As such, we propose that both IL-17A and IL-17F neutralization may be required to maximally inhibit IL-17-driven pathology.

A new method for the treatment of myocardial ischemia-reperfusion injury based on γδT cell-mediated immune response

Acute myocardial ischemia is a disease with high morbidity and mortality, and re-perfusion is currently the best intervention. However, re-perfusion may lead to further myocardial injury and increase the area of myocardial infarction. The mechanism of myocardial ischemia-re-perfusion injury is complex, but with more in-depth study, it has been proved that the immune system plays an important role in the process of MIRI. Among them, the γδT cell population has received increasing attention as the main early source of IL-17A in many immune response models. Because γδT cells have the characteristics of linking innate immunity and adaptive immunity,they can rapidly produce IL-17A and produce subsequent immune killing of cardiomyocytes. It can be seen that γδT cells play an important role in MIRI. Therefore, here we review the research progress of immune response in myocardial ischemia-re-perfusion injury, the key characteristics of γδT cells and the role of rapidly produced IL-17 in myocardial ischemia-re-perfusion injury, and propose relevant treatment strategies and prospects for myocardial repair, in order to provide new ideas and methods for clinical treatment of myocardial ischemia-re-perfusion injury.

Hydroxychloroquine reduces T cells activation recall antigen responses

BACKGROUND

In the context of the current COVID-19 pandemic, there is still limited information about how people suffering from autoimmune diseases respond to the different COVID vaccines. The fact that they are taking an immunosuppressant or other drugs that aim to decrease the immune system activities, such as hydroxychloroquine (HCQ), could also impact their ability to respond to a COVID vaccine and vaccines in general.

METHODS

Heathy donors were given 200mg of HCQ daily for 6-weeks to assess HCQs impact on the systemic T cells and humoral immune response. Peripheral blood mononuclear cells (PBMC) and plasma were obtained at baseline and 6-weeks after starting daily HCQ. Flow cytometry assays were designed to determine changes in T cell activation and T cell responses. Bead array multiplex were used to analyse antibodies and cytokine levels before and after HCQ intake.

RESULTS

As anticipated, HCQ treatment decreased ex vivo T cell activation. We observed a decrease in CD4+CD161- expressing CCR5 (p = 0.015) and CD69 (p = 0.004) as well as in CD8+CCR5+ (p = 0.003), CD8+CD161+CCR5+ (p = 0.002) and CD8+CD161+CD95+ (p = 0.004). Additionally, HCQ decreased the proportion of Th17 expressing CD29 (p = 0.019), a subset associated with persistent inflammation. The proportion of T regulatory cells expressing the inhibitory molecule TIGIT was also reduced by HCQ (p = 0.003). As well, T cells from people on HCQ were less responsive to activation and cytokine production following stimulation with recall antigens and memory T cells were less likely to produce both IFNγ and TNFα following stimulation.

CONCLUSION

This study shows HCQ is associated with lower T cell activation and decreased T cell cytokine production. While this study was not performed with the intent of looking at COVID vaccine response, it does provide important information about the changes in immune response that may occur in patient taking HCQ as a treatment for their autoimmune disease.

Chemokine Heteromers and Their Impact on Cellular Function-A Conceptual Framework

Chemoattractant cytokines or chemokines are proteins involved in numerous biological activities. Their essential role consists of the formation of gradient and (immune) cell recruitment. Chemokine biology and its related signaling system is more complex than simple ligand-receptor interactions. Beside interactions with their cognate and/or atypical chemokine receptors, and glycosaminoglycans (GAGs), chemokines form complexes with themselves as homo-oligomers, heteromers and also with other soluble effector proteins, including the atypical chemokine MIF, carbohydrate-binding proteins (galectins), damage-associated molecular patterns (DAMPs) or with chemokine-binding proteins such as evasins. Likewise, nucleic acids have been described as binding targets for the tetrameric form of CXCL4. The dynamic balance between monomeric and dimeric structures, as well as interactions with GAGs, modulate the concentrations of free chemokines available along with the nature of the gradient. Dimerization of chemokines changes the canonical monomeric fold into two main dimeric structures, namely CC- and CXC-type dimers. Recent studies highlighted that chemokine dimer formation is a frequent event that could occur under pathophysiological conditions. The structural changes dictated by chemokine dimerization confer additional biological activities, e.g., biased signaling. The present review will provide a short overview of the known functionality of chemokines together with the consequences of the interactions engaged by the chemokines with other proteins. Finally, we will present potential therapeutic tools targeting the chemokine multimeric structures that could modulate their biological functions.

The Th17/IL-17 Axis and Host Defense Against Fungal Infections

Chronic mucocutaneous candidiasis (CMC) was recognized as a primary immunodeficiency in the early 1970s. However, for almost 40 years, its genetic etiology remained unknown. The progressive molecular and cellular description of inborn errors of immunity (IEI) with syndromic CMC pointed toward a possible role of IL-17-mediated immunity in protecting against fungal infection and CMC. Since 2011, novel IEI affecting either the response to or production of IL-17A and/or IL-17F (IL-17A/F) in patients with isolated or syndromic CMC provided formal proof of the pivotal role of the IL-17 axis in mucocutaneous immunity to Candida spp, and, to a lesser extent, to Staphylococcus aureus in humans. In contrast, IL-17-mediated immunity seems largely redundant against other common microbes in humans. In this review, we outline the current knowledge of IEI associated with impaired IL-17A/F-mediated immunity, highlighting our current understanding of the role of IL-17A/F in human immunity.

Bioinformatic analysis and experimental validation of the potential gene in the airway inflammation of steroid-resistant asthma

Steroid-resistant asthma is a troublesome clinical problem in public health. The pathogenesis of steroid-resistant asthma is complex and remains to be explored. In our work, the online Gene Expression Omnibus microarray dataset GSE7368 was used to explore differentially expressed genes (DEGs) between steroid-resistant asthma patients and steroid-sensitive asthma patients. Tissue-specific gene expression of DEGs was analyzed using BioGPS. The enrichment analyses were performed using GO, KEGG, and GSEA analysis. The protein-protein interaction network and key gene cluster were constructed using STRING, Cytoscape, MCODE, and Cytohubba. A steroid-resistant neutrophilic asthma mouse model was established using lipopolysaccharide (LPS) and ovalbumin (OVA). An LPS-stimulated J744A.1 macrophage model was prepared to validate the underlying mechanism of the interesting DEG gene using the quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A total of 66 DEGs were identified, most of which were present in the hematologic/immune system. Enrichment analysis displayed that the enriched pathways were the IL-17 signaling pathway, MAPK signal pathway, Toll-like receptor signaling pathway, and so on. DUSP2, as one of the top upregulated DEGs, has not been clearly demonstrated in steroid-resistant asthma. In our study, we observed that the salubrinal administration (DUSP2 inhibitor) reversed neutrophilic airway inflammation and cytokine responses (IL-17A, TNF-α) in a steroid-resistant asthma mouse model. We also found that salubrinal treatment reduced inflammatory cytokines (CXCL10 and IL-1β) in LPS-stimulated J744A.1 macrophages. DUSP2 may be a candidate target for the therapy of steroid-resistant asthma.

Th17/Treg Imbalance: Implications in Lung Inflammatory Diseases

Regulatory T cells (Tregs) and T helper 17 cells (Th17) are two CD4⁺ T cell subsets with antagonist effects. Th17 cells promote inflammation, whereas Tregs are crucial in maintaining immune homeostasis. Recent studies suggest that Th17 cells and Treg cells are the foremost players in several inflammatory diseases. In this review, we explore the present knowledge on the role of Th17 cells and Treg cells, focusing on lung inflammatory diseases, such as chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), sarcoidosis, asthma, and pulmonary infectious diseases.

Inhibition of γδ-TcR or IL17a Reduces T-Cell and Neutrophil Infiltration after Ischemia/Reperfusion Injury in Mouse Liver

Neutrophil and T-cell recruitment contribute to hepatic ischemia/reperfusion injury. The initial inflammatory response is orchestrated by Kupffer cells and liver sinusoid endothelial cells. However, other cell types, including γδ-Τ cells, seem to be key mediators in further inflammatory cell recruitment and proinflammatory cytokine release, including IL17a. In this study, we used an in vivo model of partial hepatic ischemia/reperfusion injury (IRI) to investigate the role of the γδ-Τ-cell receptor (γδTcR) and the role of IL17a in the pathogenesis of liver injury. Forty C57BL6 mice were subjected to 60 min of ischemia followed by 6 h of reperfusion (RN 6339/2/2016). Pretreatment with either anti-γδΤcR antibodies or anti-IL17a antibodies resulted in a reduction in histological and biochemical markers of liver injury as well as neutrophil and T-cell infiltration, inflammatory cytokine production and the downregulation of c-Jun and NF-κΒ. Overall, neutralizing either γδTcR or IL17a seems to have a protective role in liver IRI.

cAMP-PDE signaling in COPD: Review of cellular, molecular and clinical features

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among non-contagious diseases in the world. PDE inhibitors are among current medicines prescribed for COPD treatment of which, PDE-4 family is the predominant PDE isoform involved in hydrolyzing cyclic adenosine monophosphate (cAMP) that regulates the inflammatory responses in neutrophils, lymphocytes, macrophages and epithelial cells The aim of this study is to investigate the cellular and molecular mechanisms of cAMP-PDE signaling, as an important pathway in the treatment management of patients with COPD. In this review, a comprehensive literature review was performed about the effect of PDEs in COPD. Generally, PDEs are overexpressed in COPD patients, resulting in cAMP inactivation and decreased cAMP hydrolysis from AMP. At normal amounts, cAMP is one of the essential agents in regulating metabolism and suppressing inflammatory responses. Low amount of cAMP lead to activation of downstream inflammatory signaling pathways. PDE4 and PDE7 mRNA transcript levels were not altered in polymorphonuclear leukocytes and CD8 lymphocytes originating from the peripheral venous blood of stable COPD subjects compared to healthy controls. Therefore, cAMP-PDE signaling pathway is one of the most important signaling pathways involved in COPD. By examining the effects of different drugs in this signaling pathway critical steps can be taken in the treatment of this disease.

Evolutional perspective and functional characteristics of interleukin-17 in teleosts

Interleukin (IL)-17 is a proinflammatory cytokine and plays essential roles in adaptive and innate immune responses against bacterial and fungal infections. Especially in mammalian mucosal tissues, it is well known that innate immune responses via IL-17A and IL-17F, such as the production of antimicrobial peptides, are very important for microbiota control. In contrast, interesting insights into the functions of IL-17 have recently been reported in several teleost species, although little research has been conducted on teleost IL-17. In the present review, we focused on current insights on teleost IL-17 and speculated on the different or consensus parts of teleost IL-17 signaling compared to that of mammals. This review focuses on the role of teleost IL-17 in intestinal immunity. We expect that this review will encourage a further understanding of the roles and importance of IL-17 signaling in teleosts.

Quercetin alleviates ferroptosis accompanied by reducing M1 macrophage polarization during neutrophilic airway inflammation

Ferroptosis is a kind of regulated cell death, supporting the pathological process of lung inflammation, including asthma. Quercetin (QCT), a kind of natural dietary flavonoid, exerts anti-inflammatory and anti-ferroptosis effects in various diseases. However, the role of QCT in ferroptosis-associated airway inflammation of neutrophilic asthma remains to be described. Our study aimed to investigate the therapeutic effects of QCT on neutrophilic airway inflammation of asthma. Ferrostatin-1 (Fer-1), as a kind of ferroptosis inhibitor, was used to demonstrate whether neutrophilic airway inflammation of asthma relied on ferroptosis. In our study, the alleviation effect of QCT on neutrophilic airway inflammation was similar to Fer-1. Moreover, the significantly decreased levels of ferroptosis anti-oxidant protein (GPX4 and SLC7A11), increased malondialdehyde (MDA) levels, upregulated levels of 4-hydroxynonenal (4-HNE) expression by immunohistochemistry, and distorted mitochondria morphological changes in the lung tissues suggested lung ferroptosis in neutrophilic airway inflammation, which could be reversed by QCT treatment. In vitro experiments showed that QCT reduced LPS-induced ferroptosis through upregulating cell viability and levels of ferroptosis anti-oxidant protein (SLC7A11 and GPX4), reducing inflammatory cytokines, and decreasing the levels of MDA. Furthermore, ferroptosis was accompanied by enhancing M1 phenotype in neutrophilic airway inflammation, and QCT suppressed ferroptosis by inhibiting the pro-inflammatory M1 profile in vitro and in vivo, just as Fer-1 did. In conclusion, our study found that QCT ameliorated ferroptosis-associated neutrophilic airway inflammation accompanied by inhibiting M1 macrophage polarization. QCT may be a promising ferroptosis inhibitor for neutrophilic airway inflammation.

The Role of Interleukin-17 in Juvenile Idiopathic Arthritis: From Pathogenesis to Treatment

Background and Objectives: Interleukin-17 (IL-17) is a cytokine family consisting of six members and five specific receptors. IL-17A was the first member to be identified in 1993. Since then, several studies have elucidated that IL-17 has predominantly pro-inflammatory activity and that its production is involved in both the defense against pathogens and the genesis of autoimmune processes. Materials and Methods: In this review, we provide an overview of the role of interleukin-17 in the pathogenesis of juvenile idiopathic arthritis (JIA) and its relationship with IL-23, the so-called IL-23-IL-17 axis, by reporting updated findings from the scientific literature. Results: Strong evidence supports the role of interleukin-17A in the pathogenesis of JIA after the deregulated production of this interleukin by both T helper 17 (Th17) cells and cells of innate immunity. The blocking of IL-17A was found to improve the course of JIA, leading to the approval of the use of the human anti-IL17A monoclonal antibody secukinumab in the treatment of the JIA subtypes juvenile psoriatic arthritis (JPsA) and enthesitis-related arthritis (ERA). Conclusions: IL-17A plays a central role in the pathogenesis of JIA. Blocking its production with specific biologic drugs enables the effective treatment of this disabling childhood rheumatic disease.

Interleukin-17 Family Cytokines in Metabolic Disorders and Cancer

Interleukin-17 (IL-17) family cytokines are potent drivers of inflammatory responses. Although IL-17 was originally identified as a cytokine that induces protective effects against bacterial and fungal infections, IL-17 can also promote chronic inflammation in a number of autoimmune diseases. Research in the last decade has also elucidated critical roles of IL-17 during cancer development and treatment. Intriguingly, IL-17 seems to play a role in the risk of cancers that are associated with metabolic disorders. In this review, we summarize our current knowledge on the biochemical basis of IL-17 signaling, IL-17′s involvement in cancers and metabolic disorders, and postulate how IL-17 family cytokines may serve as a bridge between these two types of diseases.

Flow Cytometry Sorting of Memory CCR6+CD4+ T-Cells for HIV Reservoir Quantification

Antiretroviral therapy (ART) has transformed the deadly human immunodeficiency virus type I (HIV-1) epidemic into a manageable chronic condition. Current ART is not curative and treatment interruption leads to viral rebound in people living with HIV-1 (PLWH). The main cause of viral rebound is the persistence of HIV reservoirs in long-lived memory CD4⁺ T cells. Accurate techniques to identify and quantify viral reservoirs are required to monitor therapeutic approaches designed to cure HIV infection. Th17-polarized CD4⁺ T cells are located at mucosal sites of HIV entry and are preferentially targeted for infection and viral reservoir persistence. They constitute an important reservoir in both blood and colon. In this chapter we describe a step-by-step flow cytometry-based protocol to isolate a fraction of Th17-enriched cells from PBMC based on their expression of the Th17 surface marker CCR6. The isolation of memory CCR6⁺CD4⁺ T cells allows subsequent PCR/RT-PCR-based HIV DNA/RNA quantifications, as well as their culture for quantitative viral outgrowth assays (QVOA). This method can be adapted for the isolation of CCR6⁺CD4⁺ T cells from peripheral tissues, such as the colon.

Rationalizing heptadecaphobia: TH 17 cells and associated cytokines in cancer and metastasis

Cancer is one of the leading causes of death worldwide. When cancer patients are diagnosed with metastasis, meaning that the primary tumor has spread to at least one different site, their life expectancy decreases dramatically. In the past decade, the immune system´s role in fighting cancer and metastasis has been studied extensively. Importantly, immune cells and inflammatory reactions generate potent antitumor responses but also contribute to tumor development. However, the molecular and cellular mechanisms underlying this dichotomic interaction between the immune system and cancer are still poorly understood. Recently, a spotlight has been cast on the distinct subsets of immune cells and their derived cytokines since evidence has implicated their crucial impact on cancer development. T helper 17 cell (TH 17) cells, which express the master transcriptional factor Retinoic acid-receptor-related orphan receptor gamma t, are among these critical cell subsets and are defined by their production of type 3 cytokines, such as IL-17A, IL-17F, and IL-22. Depending on the tumor microenvironment, these cytokines can also be produced by other immune cell sources, such as T cytotoxic 17 cell, innate lymphoid cells, NKT cells, or γδ T cells. To date, a lot of data have been collected describing the divergent functions of IL-17A, IL-17F, and IL-22 in malignancies. In this comprehensive review, we discuss the role of these TH 17- and non-TH 17-derived type 3 cytokines in different tumor entities. Furthermore, we will provide a structured insight into the strict regulation and subsequent downstream mechanisms of these cytokines in cancer and metastasis.

Different Phenotypes in Asthma: Clinical Findings and Experimental Animal Models

Asthma is a respiratory allergic disease presenting a high prevalence worldwide, and it is responsible for several complications throughout life, including death. Fortunately, asthma is no longer recognized as a unique manifestation but as a very heterogenic manifestation. Its phenotypes and endotypes are known, respectively, as pathologic and molecular features that might not be directly associated with each other. The increasing number of studies covering this issue has brought significant insights and knowledge that are constantly expanding. In this review, we intended to summarize this new information obtained from clinical studies, which not only allowed for the creation of patient clusters by means of personalized medicine and a deeper molecular evaluation, but also created a connection with data obtained from experimental models, especially murine models. We gathered information regarding sensitization and trigger and emphasizing the most relevant phenotypes and endotypes, such as Th2-^high asthma and Th2-^low asthma, which included smoking and obesity-related asthma and mixed and paucigranulocytic asthma, not only in physiopathology and the clinic but also in how these phenotypes can be determined with relative similarity using murine models. We also further investigated how clinical studies have been treating patients using newly developed drugs focusing on specific biomarkers that are more relevant according to the patient's clinical manifestation of the disease.

Genes involved in immune, gene translation and chromatin organization pathways associated with Mycoplasma ovipneumoniae presence in nasal secretions of domestic sheep

Mycoplasma ovipneumoniae contributes to polymicrobial pneumonia in domestic sheep. Elucidation of host genetic influences of M. ovipneumoniae nasal detection has the potential to reduce the incidence of polymicrobial pneumonia in sheep through implementation of selective breeding strategies. Nasal mucosal secretions were collected from 647 sheep from a large US sheep flock. Ewes of three breeds (Polypay n = 222, Rambouillet n = 321, and Suffolk n = 104) ranging in age from one to seven years, were sampled at three different times in the production cycle (February, April, and September/October) over four years (2015 to 2018). The presence and DNA copy number of M. ovipneumoniae was determined using a newly developed species-specific qPCR. Breed (P<0.001), age (P<0.024), sampling time (P<0.001), and year (P<0.001) of collection affected log10 transformed M. ovipneumoniae DNA copy number, where Rambouillet had the lowest (P<0.0001) compared with both Polypay and Suffolk demonstrating a possible genetic component to detection. Samples from yearlings, April, and 2018 had the highest (P<0.046) detected DNA copy number mean. Sheep genomic DNA was genotyped with the Illumina OvineHD BeadChip. Principal component analysis identified most of the variation in the dataset was associated with breed. Therefore, genome wide association analysis was conducted with a mixed model (EMMAX), with principal components 1 to 6 as fixed and a kinship matrix as random effects. Genome-wide significant (P<9x10-8) SNPs were identified on chromosomes 6 and 7 in the all-breed analysis. Individual breed analysis had genome-wide significant (P<9x10-8) SNPs on chromosomes 3, 4, 7, 9, 10, 15, 17, and 22. Annotated genes near these SNPs are part of immune (ANAPC7, CUL5, TMEM229B, PTPN13), gene translation (PIWIL4), and chromatin organization (KDM2B) pathways. Immune genes are expected to have increased expression when leukocytes encounter M. ovipneumoniae which would lead to chromatin reorganization. Work is underway to narrow the range of these associated regions to identify the underlying causal mutations.

Epithelium-derived IL17A Promotes Cigarette Smoke-induced Inflammation and Mucus Hyperproduction

Airway epithelium is a central modulator of innate and adaptive immunity in the lung. Interleukin (IL)17A expression was found to be increased in airway epithelium; however, the role of epithelial-derived IL17A in chronic obstructive pulmonary disease (COPD) remains unclear. In this study, we aim to determine whether epithelial-derived IL17A regulates inflammation and mucus hyperproduction in COPD using a cultured human bronchial epithelial (HBE) cell line in vitro and airway epithelium IL17A-specific knockout mouse in vivo. Increased IL17A expression was observed in mouse airway epithelium upon cigarette smoke (CS) exposure or in a COPD mouse model that was induced by CS and elastin. CS extract (CSE) also triggered IL17A expression in HBE cells. Blocking IL17A or IL17RA effectively attenuated CSE-induced MUC5AC and the inflammatory cytokines IL6, tumor necrosis factor (TNF)-α, and IL1β in HBE cells, suggesting that IL17A mediates CSE-induced inflammation and mucin production in an autocrine manner. CSE activated p-JUN and p-JNK, which were also reduced by IL17RA-siRNA, and JUN-siRNA attenuated CSE-induced IL6 and MUC5AC. In vivo, selective knockout of IL17A in airway epithelium markedly reduced the neutrophilic infiltration in Bronchoalveolar Lavage Fluid (BALF), peribronchial inflammation, pro-inflammatory mediators (CXCL1 and CXCL2), and mucus production in a COPD mouse model. We showed a novel function of airway epithelium-derived IL17A, which can act locally in an autocrine manner to amplify inflammation and increase mucus production in COPD pathogenesis.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Perspectives for improvement of Mycoplasma hyopneumoniae vaccines in pigs

Mycoplasma hyopneumoniae (M. hyopneumoniae) is one of the primary agents involved in the porcine respiratory disease complex, economically one of the most important diseases in pigs worldwide. The pathogen adheres to the ciliated epithelium of the trachea, bronchi, and bronchioles, causes damage to the mucosal clearance system, modulates the immune system and renders the animal more susceptible to other respiratory infections. The pathogenesis is very complex and not yet fully understood. Cell-mediated and likely also mucosal humoral responses are considered important for protection, although infected animals are not able to rapidly clear the pathogen from the respiratory tract. Vaccination is frequently practiced worldwide to control M. hyopneumoniae infections and the associated performance losses, animal welfare issues, and treatment costs. Commercial vaccines are mostly bacterins that are administered intramuscularly. However, the commercial vaccines provide only partial protection, they do not prevent infection and have a limited effect on transmission. Therefore, there is a need for novel vaccines that confer a better protection. The present paper gives a short overview of the pathogenesis and immune responses following M. hyopneumoniae infection, outlines the major limitations of the commercial vaccines and reviews the different experimental M. hyopneumoniae vaccines that have been developed and tested in mice and pigs. Most experimental subunit, DNA and vector vaccines are based on the P97 adhesin or other factors that are important for pathogen survival and pathogenesis. Other studies focused on bacterins combined with novel adjuvants. Very few efforts have been directed towards the development of attenuated vaccines, although such vaccines may have great potential. As cell-mediated and likely also humoral mucosal responses are important for protection, new vaccines should aim to target these arms of the immune response. The selection of proper antigens, administration route and type of adjuvant and carrier molecule is essential for success. Also practical aspects, such as cost of the vaccine, ease of production, transport and administration, and possible combination with vaccines against other porcine pathogens, are important. Possible avenues for further research to develop better vaccines and to achieve a more sustainable control of M. hyopneumoniae infections are discussed.

The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.

BCG-induced protection against Mycobacterium tuberculosis infection: Evidence, mechanisms, and implications for next-generation vaccines

The tuberculosis (TB) vaccine Bacillus Calmette-Guérin (BCG) was introduced 100 years ago, but as it provides insufficient protection against TB disease, especially in adults, new vaccines are being developed and evaluated. The discovery that BCG protects humans from becoming infected with Mycobacterium tuberculosis (Mtb) and not just from progressing to TB disease provides justification for considering Mtb infection as an endpoint in vaccine trials. Such trials would require fewer participants than those with disease as an endpoint. In this review, we first define Mtb infection and disease phenotypes that can be used for mechanistic studies and/or endpoints for vaccine trials. Secondly, we review the evidence for BCG-induced protection against Mtb infection from observational and BCG re-vaccination studies, and discuss limitations and variation of this protection. Thirdly, we review possible underlying mechanisms for BCG efficacy against Mtb infection, including alternative T cell responses, antibody-mediated protection, and innate immune mechanisms, with a specific focus on BCG-induced trained immunity, which involves epigenetic and metabolic reprogramming of innate immune cells. Finally, we discuss the implications for further studies of BCG efficacy against Mtb infection, including for mechanistic research, and their relevance to the design and evaluation of new TB vaccines.

Systems analysis of human T helper17 cell differentiation uncovers distinct time-regulated transcriptional modules

T helper (Th) 17 cells protect from infections and are pathogenic in autoimmunity. While human Th17 cell differentiation has been defined, the global and stepwise transcriptional changes accompanying this process remain uncharacterized. Herein, by performing transcriptome analysis of human Th17 cells, we uncovered three time-regulated modules: early, involving exclusively “signaling pathways” genes; late, characterized by response to infections; and persistent, involving effector immune functions. To assign them an inflammatory or regulatory potential, we compared Th17 cells differentiated in presence or absence of interleukin (IL)-1β, respectively. Most inflammatory genes belong to the persistent module, whereas regulatory genes are lately or persistently induced. Among inflammatory genes, we identified the effector molecules IL17A, IL17F, IL26, IL6, interferon (IFN)G, IFNK, LTA, IL1A, platelet-derived growth factor (PDGF) A and the transcriptional regulators homeodomain-only protein homeobox (HOPX) and sex-determining-region-Y-box (SOX)2, whose expression was independently validated. This study provides an integrative representation of the stepwise human Th17 differentiation program and offers new perspectives toward therapeutic targeting of Th17-related autoimmune diseases.

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Human Th17 cells are driven by early, late, and persistent transcriptional modules.

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Human Th17 cells express IL17A, IL17F, IL26, IL6, IFNG, IFNK, LTA, IL1A, and PDGFA.

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RORC regulates the IL17A, IL17F, IFNG, PDGFA, and IL1A expression in human Th17 cells.

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HOPX and SOX2 contribute to the expression of IFNG by human Th17 cells.

Viral genomic, metagenomic and human transcriptomic characterization and prediction of the clinical forms of COVID-19

COVID-19 is characterized by respiratory symptoms of various severities, ranging from mild upper respiratory signs to acute respiratory failure/acute respiratory distress syndrome associated with a high mortality rate. However, the pathophysiology of the disease is largely unknown. Shotgun metagenomics from nasopharyngeal swabs were used to characterize the genomic, metagenomic and transcriptomic features of patients from the first pandemic wave with various forms of COVID-19, including outpatients, patients hospitalized not requiring intensive care, and patients in the intensive care unit, to identify viral and/or host factors associated with the most severe forms of the disease. Neither the genetic characteristics of SARS-CoV-2, nor the detection of bacteria, viruses, fungi or parasites were associated with the severity of pulmonary disease. Severe pneumonia was associated with overexpression of cytokine transcripts activating the CXCR2 pathway, whereas patients with benign disease presented with a T helper "Th1-Th17" profile. The latter profile was associated with female gender and a lower mortality rate. Our findings indicate that the most severe cases of COVID-19 are characterized by the presence of overactive immune cells resulting in neutrophil pulmonary infiltration which, in turn, could enhance the inflammatory response and prolong tissue damage. These findings make CXCR2 antagonists, in particular IL-8 antagonists, promising candidates for the treatment of patients with severe COVID-19.

Protection Elicited by Attenuated Live Yersinia pestis Vaccine Strains against Lethal Infection with Virulent Y. pestis

The etiologic agent of plague, Yersinia pestis, is a globally distributed pathogen which poses both a natural and adversarial threat. Due largely to the rapid course and high mortality of pneumonic plague, vaccines are greatly needed. Two-component protein vaccines have been unreliable and potentially vulnerable to vaccine resistance. We evaluated the safety and efficacy of eight live Y. pestis strains derived from virulent strains CO92 or KIM6+ and mutated in one or more virulence-associated gene(s) or cured of plasmid pPst. Stringent, single-dose vaccination allowed down-selection of the two safest and most protective vaccine candidates, CO92 mutants pgm- pPst- and ΔyscN. Both completely protected BALB/c mice against subcutaneous and aerosol challenge with Y. pestis. Strain CD-1 outbred mice were more resistant to bubonic (but not pneumonic) plague than BALB/c mice, but the vaccines elicited partial protection of CD-1 mice against aerosol challenge, while providing full protection against subcutaneous challenge. A ΔyscN mutant of the nonencapsulated C12 strain was expected to display antigens previously concealed by the capsule. C12 ΔyscN elicited negligible titers to F1 but comparable antibody levels to whole killed bacteria, as did CO92 ΔyscN. Although one dose of C12 ΔyscN was not protective, vaccination with two doses of either CO92 ΔyscN, or a combination of the ΔyscN mutants of C12 and CO92, protected optimally against lethal bubonic or pneumonic plague. Protection against encapsulated Y. pestis required inclusion of F1 in the vaccine and was associated with high anti-F1 titers.

Modern View of Neutrophilic Asthma Molecular Mechanisms and Therapy

For a long time asthma was commonly considered as a homogeneous disease. However, recent studies provide increasing evidence of its heterogeneity and existence of different phenotypes of the disease. Currently, classification of asthma into several phenotypes is based on clinical and physiological features, anamnesis, and response to therapy. This review describes five most frequently identified asthma phenotypes. Neutrophilic asthma (NA) deserves special attention, since neutrophilic inflammation of the lungs is closely associated with severity of the disease and with the resistance to conventional corticosteroid therapy. This review focuses on molecular mechanisms of neutrophilic asthma pathogenesis and on the role of Th1- and Th17-cells in the development of this type of asthma. In addition, this review presents current knowledge of neutrophil biology. It has been established that human neutrophils are represented by at least three subpopulations with different biological functions. Therefore, total elimination of neutrophils from the lungs can result in negative consequences. Based on the new knowledge of NA pathogenesis and biology of neutrophils, the review summarizes current approaches for treatment of neutrophilic asthma and suggests new promising ways to treat this type of asthma that could be developed in future.

Interleukin- 17agene Polymorphism, Serum Level and Its Tissue Expression in Iraqi Patients Gastric Lesions

BACKGROUND

T-helper 17 plays a novel role in inflammation in gastritis by producing IL-17A, IL-17A gene polymorphisms that might be responsible for disease susceptibility and development of different gastric lesions.

OBJECTIVE

The aims of study was to determine the association of IL-17A (G197A) genotype and allele frequency with disease phenotype and risk with different gastric lesions.

METHODS

Case controlled study involved 30 gastroduodenal ulcer, 30 chronic gastritis and 30 subjects as a control group with negative endoscopic findings. After genomic DNA extraction, IL-17A (G197A)ARMS-PCR genotyping were done for all cases. Serum IL-17A was measured using ELISA method and tissue expression was visualized using immunohistochemistry staining method.

RESULTS

The results showed that allele A was significantly frequent in gastroduodenal ulcer more than that in healthy control odd ratio= 4 (1.42-10.46), and none significantly with chronic gastritis p=0.071. Serum IL-17A was significantly higher in gastroduodenal ulcer (116.45±48.09 pg/ml), chronic gastritis (78.02±30.17pg/ml) and healthy control 19.36±9.28 pg/ml).However, the serum IL-17A level is not related to the allele pattern of each group. The tissue expression was expressed as dense granular cytoplasmic and membranous of inflammatory cells. Interestingly, the percentage of IL-17A protein expression was significantly higher in gastroduodenal ulcer (38.2±16.55%), chronic gastritis (30.89±14.02%) and normal mucosa (2.8±3.02%). Furthermore, patients with strong intensity of IL-17A stained mucosa were frequently carrier for mutant allele (68%).

CONCLUSION

IL-17A might predispose for aggressive inflammation of advanced lesions in stomach like ulcer.

Regulation of Immune Responses by Nonhematopoietic Cells in Asthma

Nonhematopoietic cells are emerging as important contributors to many inflammatory diseases, including allergic asthma. Recent advances have led to a deeper understanding of how these cells interact with traditional immune cells, thereby modulating their activities in both homeostasis and disease. In addition to their well-established roles in gas exchange and barrier function, lung epithelial cells express an armament of innate sensors that can be triggered by various inhaled environmental agents, leading to the production of proinflammatory molecules. Advances in cell lineage tracing and single-cell RNA sequencing have expanded our knowledge of rare, but immunologically important nonhematopoietic cell populations. In parallel with these advances, novel reverse genetic approaches are revealing how individual genes in different lung-resident nonhematopoietic cell populations contribute to the initiation and maintenance of asthma. This knowledge is already revealing new pathways that can be selectively targeted to treat distinct forms of asthma.

Assessment of the pulmonary adaptive immune response to Cladosporium cladosporioides infection using an experimental mouse model

Cladosporium cladosporioides causes asthma and superficial and deep infections, mostly in immunodeficient individuals and animals. This study aimed to investigate whether C. cladosporioides spores can enter the lungs through pulmonary circulation and influence pulmonary immune response. We intravenously injected mice with C. cladosporioides spore suspension and conducted several assays on the lungs. Pulmonary hemorrhage symptoms and congestion were most severe on days 1, 2, and 3 post-inoculation (PI). Extensive inflammatory cell infiltration occurred throughout the period of infection. More spores and hyphae colonizing the lungs were detected on days 1, 2, and 3 PI, and fewer spores and hyphae were observed within 21 d of infection. Numerous macrophages, dendritic cells, and neutrophils were observed on day 5 PI, along with upregulation of CD54, an intercellular adhesion molecule. Th1 and Th2 cells increased after infection; specifically, Th2 cells increased considerably on day 5 PI. These results suggest that days 2 and 5 PI represent the inflammatory peak in the lungs and that the Th2 and Th1 signaling pathways are potentially involved in pulmonary immune responses. In conclusion, the further adaptive immune responses played important roles in establishing effective pulmonary immunity against C. cladosporioides systemic infections based on innate immune responses.

Acupuncture for Asthma: Its Potential Significance in Clinical Practice

Acupuncture has been used for the prevention and treatment of asthma. However, the mechanisms underlying the effects of acupuncture in asthma are not fully understood. This article discusses the possible mechanisms underlying the effects of acupuncture in the prevention and treatment of asthma. Existing evidence has shown that acupuncture might facilitate the prevention and treatment of asthma via its anti-inflammatory effects. Acupuncture has been shown to modulate Th1/Th2 balance, block inflammatory cells and mediators, improve airway remodeling, and regulate hypothalamic-pituitary-adrenal axis function. Acupuncture appears to exert its antiasthmatic properties through multiple pathways.

IL-17F induces inflammation, dysfunction and cell death in mouse islets

Type 17 immune responses, typified by the production of the cytokines IL-17A and IL-17F, have been implicated in the development of type 1 diabetes in animal models and human patients, however the underlying pathogenic mechanisms have not been clearly elucidated. While previous studies show that IL-17A enhances inflammatory gene expression and cell death in mouse β-cells and human islets, the function of IL-17F in pancreatic β-cells is completely untested to date. Here we show that IL-17F exhibits potent pathogenic effects in mouse β-cell lines and islets. IL-17F signals via the IL-17RA and -RC subunits in β-cells and in combination with other inflammatory cytokines induces expression of chemokine transcripts, suppresses the expression of β-cell identity genes and impairs glucose stimulated insulin secretion. Further IL-17F induces cell death in primary mouse islets. This occurs via Jnk, p38 and NF-κB dependent induction of Nos2 and is completely ablated in the presence of an inducible nitric oxide synthase (iNOS) inhibitor. Together these data indicate that IL-17F possesses similar pathogenic activities to IL-17A in mouse β-cell lines and islets and is likely to be a type 17 associated pathogenic factor in type 1 diabetes.

Inflammatory Cells in Diffuse Large B Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL), known as the most common non-Hodgkin lymphoma (NHL) subtype, is characterized by high clinical and biological heterogeneity. The tumor microenvironment (TME), in which the tumor cells reside, is crucial in the regulation of tumor initiation, progression, and metastasis, but it also has profound effects on therapeutic efficacy. The role of immune cells during DLBCL development is complex and involves reciprocal interactions between tumor cells, adaptive and innate immune cells, their soluble mediators and structural components present in the tumor microenvironment. Different immune cells are recruited into the tumor microenvironment and exert distinct effects on tumor progression and therapeutic outcomes. In this review, we focused on the role of macrophages, Neutrophils, T cells, natural killer cells and dendritic cells in the DLBCL microenvironment and their implication as target for DLBCL treatment. These new therapies, carried out by the induction of adaptive immunity through vaccination or passive of immunologic effectors delivery, enhance the ability of the immune system to react against the tumor antigens inducing the destruction of tumor cells.

Interleukin-17 cytokines: Effectors and targets in psoriasis-A breakthrough in understanding and treatment

This review summarizes the steps from basic research on IL-17 family cytokines to understanding their role in psoriasis pathogenesis to the approval of a number of monoclonal antibodies targeting IL-17 pathways as first line treatment of psoriasis and psoriatic arthritis.

The IL-17 cytokine family comprising IL-17A to IL-17F and receptor subunits IL-17RA to IL-17RE represents a genetically ancient intercellular network regulating local tissue homeostasis. Its pivotal role in antifungal defense and its central position in the pathogenesis of inflammatory diseases including psoriasis were discovered only relatively late in the early 2000s. Since the connection of dysregulated IL-17 and psoriasis pathogenesis turned out to be particularly evident, a number of monoclonal antibodies targeting IL-17 pathways have been approved and are used as first line treatment of moderate-to-severe plaque psoriasis and psoriatic arthritis, and further agents are currently in clinical development.

Cyclic AMP in dendritic cells: A novel potential target for disease-modifying agents in asthma and other allergic disorders

Allergic diseases are immune disorders that are a global health problem, affecting a large portion of the world's population. Allergic asthma is a heterogeneous disease that alters the biology of the airway. A substantial portion of patients with asthma do not respond to conventional therapies; thus, new and effective therapeutics are needed. Dendritic cells (DCs), antigen presenting cells that regulate helper T cell differentiation, are key drivers of allergic inflammation but are not the target of current therapies. Here we review the role of dendritic cells in allergic conditions and propose a disease-modifying strategy for treating allergic asthma: cAMP-mediated inhibition of dendritic cells to blunt allergic inflammation. This approach contrasts with current treatments that focus on treating clinical manifestations of airway inflammation. Disease-modifying agents that target cAMP and its signalling pathway in dendritic cells may provide a novel means to treat asthma and other allergic diseases.

Role of TH17 Responses in Increasing Herpetic Keratitis in the Eyes of Mice Infected with HSV-1

Purpose

T_H17 cells play an important role in host defense and autoimmunity yet very little is known about the role of IL17 in herpes simplex virus (HSV)-1 infectivity. To better understand the relationship between IL17 and HSV-1 infection, we assessed the relative impact of IL17A-deficiency and deficiency of its receptors on HSV-1 responses in vivo.

Methods

We generated IL17RA^−/− and IL17RA^−/−RC^−/− mice in-house and infected them along with IL17A^−/− and IL17RC^−/− mice in the eyes with 2 × 10⁵ PFU/eye of wild type (WT) HSV-1 strain McKrae. WT C57BL/6 mice were used as control. Virus replication in the eye, survival, corneal scarring (CS), angiogenesis, levels of latency-reactivation, and levels of CD8 and exhaustion markers (PD1, TIM3, LAG3, CTLA4, CD244, and CD39) in the trigeminal ganglia (TG) of infected mice were determined on day 28 postinfection.

Results

No significant differences in virus replication in the eye, survival, latency, reactivation, and exhaustion markers were detected among IL17A^−/−, IL17RA^−/−, IL17RC^−/−, IL17RA^−/−RC^−/−, and WT mice. However, mice lacking IL17 had significantly less CS and angiogenesis than WT mice. In addition, angiogenesis levels in the absence of IL17RC and irrespective of the absence of IL17RA were significantly less than in IL17A- or IL17RA-deficient mice.

Conclusions

Our results suggest that the absence of IL17 protects against HSV-1-induced eye disease, but has no role in protecting against virus replication, latency, or reactivation. In addition, our data provide rationale for blocking IL17RC function rather than IL17A or IL17RA function as a key driver of HSV-1-induced eye disease.

Airway Remodeling in Asthma

Asthma is an inflammatory disease of the airways that may result from exposure to allergens or other environmental irritants, resulting in bronchoconstriction, wheezing, and shortness of breath. The structural changes of the airways associated with asthma, broadly referred to as airway remodeling, is a pathological feature of chronic asthma that contributes to the clinical manifestations of the disease. Airway remodeling in asthma constitutes cellular and extracellular matrix changes in the large and small airways, epithelial cell apoptosis, airway smooth muscle cell proliferation, and fibroblast activation. These pathological changes in the airway are orchestrated by crosstalk of different cell types within the airway wall and submucosa. Environmental exposures to dust, chemicals, and cigarette smoke can initiate the cascade of pro-inflammatory responses that trigger airway remodeling through paracrine signaling and mechanostimulatory cues that drive airway remodeling. In this review, we explore three integrated and dynamic processes in airway remodeling: (1) initiation by epithelial cells; (2) amplification by immune cells; and (3) mesenchymal effector functions. Furthermore, we explore the role of inflammaging in the dysregulated and persistent inflammatory response that perpetuates airway remodeling in elderly asthmatics.