Antimicrobial Immunity Research Articles

Fungicidal activity of peptides encoded by immunoglobulin genes

Evidence from previous works disclosed the antimicrobial, antiviral, anti-tumour and/or immunomodulatory activity exerted, through different mechanisms of action, by peptides expressed in the complementarity-determining regions or even in the constant region of antibodies, independently from their specificity and isotype. Presently, we report the selection, from available databases, of peptide sequences encoded by immunoglobulin genes for the evaluation of their potential biological activities. Synthetic peptides representing the translated products of J lambda and J heavy genes proved to act in vitro against pathogenic fungi, entering yeast cells and causing their death, and exerted a therapeutic effect in a Galleria mellonella model of infection by Candida albicans. No haemolytic, cytotoxic and genotoxic effects were observed on mammalian cells. These findings raise the hypothesis that antibodies could be the evolutionary result of the adaptive combination of gene products ancestrally devoted to innate antimicrobial immunity.

Wip1 Deficiency Promotes Neutrophil Recruitment to the Infection Site and Improves Sepsis Outcome.

Sepsis is defined as an uncontrolled host response to infection, and no specific therapy or drugs have been used in clinical trials currently. Discovering new therapeutic targets for sepsis treatment has always been a central problem in the field of sepsis research. Neutrophils stand at the first line in controlling infection and have been identified to be dysregulated with impaired migration and antimicrobial function during sepsis. Based on our previous results on demonstrating wild-type p53-induced phosphatase 1 in controlling neutrophil development, we explored the possible relationship among Wip1, neutrophils, and sepsis in the present study. Wip1-deficient mice exhibited improved outcomes in cecal ligation and puncture (CLP)-induced sepsis model with enhanced bacterial clearance and less multi-organ damage. The protection seen in Wip1 KO mice was mainly due to an increased accumulation of neutrophils in the primary infectious locus mediated by the decreased internalization of CXCR2, as well as by an increased antimicrobial function. Additionally, we also identified a negative correlation between CXCR2 and Wip1 in human neutrophils during sepsis. Pharmacological inhibition of Wip1 with its inhibitor can also prevent the internalization of CXCR2 on human neutrophils treated with lipopolysaccharides in vitro and significantly improve the outcome in CLP-induced sepsis model. Taken together, our results demonstrate that Wip1 can negatively regulate neutrophil migration and antimicrobial immunity during sepsis and inhibition of Wip1 can be a potential therapeutic target for sepsis treatment.

Chronic lung inflammation primes humoral immunity and augments antipneumococcal resistance

Airway epithelial cells (AECs) display remarkable plasticity in response to infectious stimuli and their functional adaptations are critical for antimicrobial immunity. However, the roles of AECs and humoral mediators to host defense in non-communicable lung inflammation remain elusive. We dissected pulmonary defense against Streptococcus pneumoniae in hosts with pre-existing inflammatory conditions (SPC-HAxTCR-HA mice). Lung tissue transcriptomics and bronchoalveolar lavage fluid (BALF) proteomics revealed an induction of humoral defense mechanisms in inflamed lungs. Accordingly, besides antibacterial proteins and complement components being overrepresented in inflamed lungs, elevated polymeric immunoglobulin receptor (pIgR)-expression in AECs correlated with increased secretory immunoglobulin (SIg) transport. Consequently, opsonization assays revealed augmented pneumococcal coverage by SIgs present in the BALF of SPC-HAxTCR-HA mice, which was associated with enhanced antipneumococcal resistance. These findings emphasize the immunologic potential of AECs as well as their central role in providing antibacterial protection and put forward pIgR as potential target for therapeutic manipulation in infection-prone individuals.

Coordination of Bactericidal and Iron Regulatory Functions of Hepcidin in Innate Antimicrobial Immunity in a Zebrafish Model

Hepcidin acts as both an antimicrobial peptide and a hormonal regulator of iron homeostasis; however, the biological significance of this dual-function in immune reactions remains elusive. In this study, we provide experimental evidence regarding the coordination of this dual-function in the innate antimicrobial immunity using a zebrafish model. The transcription of hepcidin gene was significantly upregulated in liver by Aeromonas hydrophila (A.h) DNA stimulation, which was accompanied by an increase of hepcidin protein and a decrease of iron concentration in serum. Thus, an enhanced bactericidal activity against A.h and Escherichia coli and inhibitory effects on A.h growth and OmpA expression were observed in A.h cells, the latter of which made the bacterium more susceptible to complement attack. The enhanced bacteriostatic activities in serum following the stimulation were dramatically impaired by neutralizing hepcidin or restoring iron to the samples. Immuno-protection assay showed that zebrafish administrated with A.h DNA or designed CpG-ODNs had a significantly enhanced defence against A.h and Vibrio alginolyticus infections, which was also eliminated by the neutralization of hepcidin. Results indicate that the induction of hepcidin leads to the decrease of iron in circulation, which eventually limits iron availability to invading microorganisms, thus contributing to host defence.

Cytokines regulate complement receptor immunoglobulin expression and phagocytosis of Candida albicans in human macrophages: A control point in anti-microbial immunity

Complement Receptor Immunoglobulin (CRIg), selectively expressed by macrophages, plays an important role in innate immunity by promoting phagocytosis of bacteria. Thus modulation of CRIg on macrophages by cytokines can be an important mechanism by which cytokines regulate anti-microbial immunity. The effects of the cytokines, tumor necrosis factor, transforming growth factor-β1, interferon-γ, interleukin (IL)-4, IL-13, IL-10, IL-1β, IL-6, lymphotoxin-α, macrophage-colony stimulating factor (M-CSF) and GM-CSF on CRIg expression were examined in human macrophages. We demonstrated that cytokines regulated the CRIg expression on macrophages during their development from monocytes in culture at the transcriptional level using qPCR and protein by Western blotting. Both CRIg spliced forms (Long and Short), were similarly regulated by cytokines. Direct addition of cytokines to matured CRIg+ macrophages also changed CRIg mRNA expression, suggesting that cytokines control macrophage function via CRIg, at two checkpoints. Interestingly the classical complement receptors, CR3 and CR4 were differentially regulated by cytokines. The changes in CRIg but not CR3/CR4 mRNA expression correlated with ability to phagocytose Candida albicans by macrophages. These findings suggest that CRIg is likely to be a control point in infection and immunity through which cytokines can mediate their effects, and is differentially regulated from CR3 and CR4 by cytokines.

Signaling C-type lectin receptors in antimycobacterial immunity.

The mammalian innate immune system is composed of phagocytes such as macrophages and dendritic cells that serve as the first line of defense against microbial infections. These cells express various pattern recognition receptors (PRRs) that recognize specific pathogen-associated molecular patterns (PAMPs) on the surface of or inside microorganisms [1]. PRRs such as Toll-like receptors (TLRs), C-type lectin receptors (CLRs), and Nucleotide-binding Oligomerization Domain (NOD)-like receptors (NLRs) have been widely studied in antimicrobial immunity and homeostasis. These PRRs have also been implicated in antimycobacterial immunity, with CLRs recently receiving considerable attention. CLRs are a large family of proteins containing at least 1 carbohydrate-recognition domain (CRD) that in most cases binds a range of carbohydrate-based PAMPs, including trehalose 6,6’ dimycolate (TDM), lipoarabinomannan (LAM), lipomannan (LM), and phosphatidylinositol mannosides (PIMs) [2–4]. Interactions of CLRs with mycobacterial PAMPs induce intracellular signaling that triggers responses ranging from cytokine production to induction of adaptive immunity (Table 1). Here, we discuss signaling CLRs that recognize mycobacterial PAMPs and contribute to antimycobacterial immunity. We focus on the receptors that signal through the Spleen tyrosine kinase (Syk)/Caspase recruitment domain family member 9 (CARD9) pathway, including Dectin-1, Dectin-2, macrophage-inducible C-type lectin (Mincle), C-type lectin superfamily member 8 (Clecsf8) also called macrophage C-type lectin (MCL), and dendritic cell immunoactivating receptor (DCAR) (Fig 1). Table 1 C-type lectin receptors, mycobacterial ligands, and their effects on pro-inflammatory cytokine production and contributions in host resistance to mycobacterial infections in vivo. C-type lectin receptor Mtb ligand Cellular expression Effects on pro-inflammatory cytokine production Role in host resistance to mycobacterial infection References Dectin-1 unknown DCs, monocytes, macrophages, neutrophils, eosinophils, mast cells, and lung epithelium ↑IL-6, IL-23, IL-1β, TNF-α, IL-12p40, and IL-17 Dispensable for host resistance to Mycobacterium tuberculosis H37Rv infection in mice [5, 7, 9–11, 35] Dectin-2 ManLAM DCs, monocytes, tissue macrophages, CD8+ T cells, and CD19+ B cells ↑TNF-α, IL-6, and IL-17 Survival studies not performed. Required to control lung damage during M. avium infection. [4, 12, 14, 36] Mincle TDM Monocytes, macrophages, neutrophils, myeloid DCs, and B cells. ↑IL-8, IL-6 andIL-1β Required for bacterial clearance. Inconsistent results on essentiality. [4, 17, 19, 21–23] ClecSF8 (MCL) TDM Neutrophils, monocytes, and DCs ↑IL-6, TNF-α and IL-1β Required for resistance to M. bovis BCG and M. tuberculosis H37Rv infection in mice [25, 28, 29] Mannose receptor ManLAM, DIM, mannosylated proteins Macrophages and MDCs ↑IFN-γ Survival studies not performed [10, 34, 37, 38] DC-SIGN ManLAM, PIMs, mannosylated glycoproteins Myeloid DCs and macrophages ↑IFN-γ hSIGN transgenic mice resistant to high-dose M. tuberculosis H37Rv infection. SIGNR3 KO mice have elevated CFUs. [10, 32, 33, 39] DCAR PIMs Peritoneal macrophages, monocyte-derived inflammatory cells in lung and spleen ↑IFN-γ and IL-12 Survival studies not performed. High CFU in DCAR KO mice infected with BCG or H37Rv. [4, 31] Open in a separate window Abbreviations: CFU, colony-forming unit; ClecSF8, C-type lectin superfamily member 8; DC, dendritic cells; DC-SIGN, Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin; DCAR, dendritic cell immunoactivating receptor; DIM, Phthiol Dimycocerosates; KO, knock-out; ManLAM, Mannose-caped Lipoarabinomannan; Mincle, macrophage-inducible C-type lectin; MCL, macrophage C-type lectin; Mtb, Mycobacterium tuberculosis; PIM, Phosphatidyinositol Mannosides; TDM, Trehalose Dimycolate.

E. coli promotes human V\u03b39V\u03b42\u2009T cell transition from cytokine-producing bactericidal effectors to professional phagocytic killers in a TCR-dependent manner

γδT cells provide immune-surveillance and host defense against infection and cancer. Surprisingly, functional details of γδT cell antimicrobial immunity to infection remain largely unexplored. Limited data suggests that γδT cells can phagocytose particles and act as professional antigen-presenting cells (pAPC). These potential functions, however, remain controversial. To better understand γδT cell-bacterial interactions, an ex vivo co-culture model of human peripheral blood mononuclear cell (PBMC) responses to Escherichia coli was employed. Vγ9Vδ2 cells underwent rapid T cell receptor (TCR)-dependent proliferation and functional transition from cytotoxic, inflammatory cytokine immunity, to cell expansion with diminished cytokine but increased costimulatory molecule expression, and capacity for professional phagocytosis. Phagocytosis was augmented by IgG opsonization, and inhibited by TCR-blockade, suggesting a licensing interaction involving the TCR and FcγR. Vγ9Vδ2 cells displayed potent cytotoxicity through TCR-dependent and independent mechanisms. We conclude that γδT cells transition from early inflammatory cytotoxic killers to myeloid-like APC in response to infectious stimuli.

Quantitative and qualitative iNKT repertoire associations with disease susceptibility and outcome in macaque tuberculosis infection

Correlates of immune protection that reliably predict vaccine efficacy against Mycobacterium tuberculosis (Mtb) infection are urgently needed. Invariant NKT cells (iNKTs) are CD1d-dependent innate T cells that augment host antimicrobial immunity through production of cytokines, including interferon (IFN)-γ and tumour necrosis factor (TNF)-α. We determined peripheral blood iNKT numbers, their proliferative responses and iNKT subset proportions after in vitro antigen expansion by α-galactosylceramide (αGC) in a large cohort of mycobacteria-naïve non-human primates, and macaques from Bacillus Calmette-Guerin (BCG) vaccine and Mtb challenge studies. Animals studied included four genetically distinct groups of macaques within cynomolgus and rhesus species that differ in their susceptibility to Mtb infection. We demonstrate significant differences in ex vivo iNKT frequency between groups, which trends towards an association with susceptibility to Mtb, but no significant difference in overall iNKT proliferative responses. Susceptible animals exhibited a skewed CD4+/CD8+ iNKT subset ratio in comparison to more Mtb-resistant groups. Correlation of iNKT subsets post BCG vaccination with clinical disease manifestations following Mtb challenge in the Chinese cynomolgus and Indian rhesus macaques identified a consistent trend linking increased CD8+ iNKTs with favourable disease outcome. Finally, a similar iNKT profile was conferred by BCG vaccination in rhesus macaques. Our study provides the first detailed characterisation of iNKT cells in macaque tuberculosis infection, suggesting that iNKT repertoire differences may impact on disease outcome, which warrants further investigation.

The Cytokine Response to Lipopolysaccharide Does Not Predict the Host Response to Infection.

The magnitude of the LPS-elicited cytokine response is commonly used to assess immune function in critically ill patients. A suppressed response, known as endotoxin tolerance, is associated with worse outcomes, yet endotoxin tolerance-inducing TLR4 ligands are known to protect animals from infection. Thus, it remains unknown whether the magnitude of the LPS-elicited cytokine response provides an accurate assessment of antimicrobial immunity. To address this, the ability of diverse TLR ligands to modify the LPS-elicited cytokine response and resistance to infection were assessed. Priming of mice with LPS, monophosphoryl lipid A (MPLA), or poly(I:C) significantly reduced plasma LPS-elicited proinflammatory cytokines, reflecting endotoxin tolerance, whereas CpG-ODN-primed mice showed augmented cytokine production. In contrast, LPS, MPLA, and CpG-ODN, but not poly(I:C), improved the host response to a Pseudomonas aeruginosa infection. Mice primed with protective TLR ligands, including CpG-ODN, showed reduced plasma cytokines during P. aeruginosa infection. The protection imparted by TLR ligands persisted for up to 15 d yet was independent of the adaptive immune system. In bone marrow-derived macrophages, protective TLR ligands induced a persistent metabolic phenotype characterized by elevated glycolysis and oxidative metabolism as well as augmented size, granularity, phagocytosis, and respiratory burst. Sustained augmentation of glycolysis in TLR-primed cells was dependent, in part, on hypoxia-inducible factor 1-α and was essential for increased phagocytosis. In conclusion, the magnitude of LPS-elicited cytokine production is not indicative of antimicrobial immunity after exposure to TLR ligands. Additionally, protective TLR ligands induce sustained augmentation of phagocyte metabolism and antimicrobial function.

Treatment with Anti‐PD‐L1 Antibody improves antimicrobial immunity during burn wound Sepsis

BackgroundPatients with large burns are highly susceptible to infection and sepsis, partly due to immune system dysfunction. Lymphocyte dysfunction is increasingly being recognized as playing a key role in sepsis pathophysiology. Previous studies show that, the interaction between programmed death‐1 (PD‐1) on T cells and its ligand, programmed death ligand‐1 (PD‐L1) on antigen presenting cells, will inhibit T cell functions and significantly contribute to sepsis‐induced T cell dysfunction. This not only causes impaired ability to clear existing pathogens, but also renders the host susceptible to opportunistic infections. The factors that contribute to burn‐associated immune system dysfunction are not completely understood. Clinical studies from our laboratory show that PD‐1 and PD‐L1 expression are increased on circulating T cells and monocytes, respectively, from patients who ultimately die following severe burns, as compared to survivors. Therefore, studies were undertaken to evaluate the therapeutic potential of anti‐PD‐L1 antibody in a clinically relevant mouse model of burn wound infection and sepsis.Methods10–12 weeks old male BALB/c mice were subjected to 35% total body surface area full thickness burn and the wound was infected with Pseudomonas aeruginosa on day 4 post‐burn. Flow cytometry was used to characterize the numbers and phenotype of CD4+ and CD8+ T cells and antigen presenting cells in spleen and wound draining lymph nodes. Anti‐PD‐L1 antibody (50 μg, i.p.) was administered on day 3 following burn injury (one day prior to infection) to determine its effect on the pathogenesis of burn wound infection.ResultsSepsis was evident in our model of burn wound infection, as Pseudomonas aeruginosa was detected at significant levels in the blood and lungs of wound infected mice, leading to multi‐organ injury (increased markers of liver and kidney injury) and high mortality rate (>90%) by seven days post infection. The absolute lymphocyte count was significantly decreased (>80%) in the blood at day 2 post infection. Sepsis caused an increase in the expression of PD‐L1 on antigen presenting cells, including dendritic cells, F4/80+ macrophages and Ly6C+ inflammatory monocytes in the spleen. There was no change in PD‐1 expression on CD4+ and CD8+ T cells. Treatment with anti‐PD‐L1 antibody inhibited the systemic spread of infection, as evidenced by significantly decreased levels of Pseudomonas aeruginosa in the blood and lungs of anti‐PD‐L1 treated mice as compared to mice treated with isotype control antibody. Importantly, treatment with anti‐PD‐L1 antibody significantly improved survival rate (>80%) post sepsis, as compared to mice treated with isotype control antibody (<10% survival).ConclusionAnti‐PD‐L1 antibody represents a novel therapeutic agent, with a strong potential to reverse immunosuppression and improve survival during burn wound sepsis, which merits further investigation.Support or Funding InformationN.K.P is supported by a Postdoctoral Grant from the American Heart Association (16POST29920007) and this work is also supported by the National Institute of Health grant NIH R01 GM66885 to E.R.S

Antimicrobial Activity of Mesenchymal Stem Cells: Current Status and New Perspectives of Antimicrobial Peptide-Based Therapies.

While mesenchymal stem cells (MSCs)-based therapy appears to be promising, there are concerns regarding possible side effects related to the unwanted suppression of antimicrobial immunity leading to an increased risk of infection. Conversely, recent data show that MSCs exert strong antimicrobial effects through indirect and direct mechanisms, partially mediated by the secretion of antimicrobial peptides and proteins (AMPs). In fact, MSCs have been reported to increase bacterial clearance in preclinical models of sepsis, acute respiratory distress syndrome, and cystic fibrosis-related infections. This article reviews the current evidence regarding the direct antimicrobial effector function of MSCs, focusing mainly on the role of MSCs-derived AMPs. The strategies that might modulate the expression and secretion of these AMPs, leading to enhanced antimicrobial effect, are highlighted. Furthermore, studies evaluating the presence of AMPs in the cargo of extracellular vesicles (EVs) are underlined as perspective opportunities to develop new drug delivery tools. The antimicrobial potential of MSCs-derived EVs can also be heightened through cell conditioning and/or drug loading. Finally, improving the pharmacokinetics and delivery, in addition to deciphering the multi-target drug status of AMPs, should synergistically lead to key advances against infections caused by drug-resistant strains.

Defective Lymphatics in Crohn’s Disease: Tertiary Lymphoid Follicles Plug the Gap

Defective Lymphatics in Crohn’s Disease: Tertiary Lymphoid Follicles Plug the Gap

Canonical and Non-Canonical Aspects of JAK-STAT Signaling: Lessons from Interferons for Cytokine Responses.

Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signal transduction mediates cytokine responses. Canonical signaling is based on STAT tyrosine phosphorylation by activated JAKs. Downstream of interferon (IFN) receptors, activated JAKs cause the formation of the transcription factors IFN-stimulated gene factor 3 (ISGF3), a heterotrimer of STAT1, STAT2 and interferon regulatory factor 9 (IRF9) subunits, and gamma interferon-activated factor (GAF), a STAT1 homodimer. In recent years, several deviations from this paradigm were reported. These include kinase-independent JAK functions as well as extra- and intranuclear activities of U-STATs without phosphotyrosines. Additionally, transcriptional control by STAT complexes resembling neither GAF nor ISGF3 contributes to transcriptome changes in IFN-treated cells. Our review summarizes the contribution of non-canonical JAK–STAT signaling to the innate antimicrobial immunity imparted by IFN. Moreover, we touch upon functions of IFN pathway proteins beyond the IFN response. These include metabolic functions of IRF9 as well as the regulation of natural killer cell activity by kinase-dead TYK2 and different phosphorylation isoforms of STAT1.

C-type lectin receptor DCIR modulates immunity to tuberculosis by sustaining type I interferon signaling in dendritic cells

Immune response against pathogens is a tightly regulated process that must ensure microbial control while preserving integrity of the infected organs. Tuberculosis (TB) is a paramount example of a chronic infection in which antimicrobial immunity is protective in the vast majority of infected individuals but can become detrimental if not finely tuned. Here, we report that C-type lectin dendritic cell (DC) immunoreceptor (DCIR), a key component in DC homeostasis, is required to modulate lung inflammation and bacterial burden in TB. DCIR is abundantly expressed in pulmonary lesions in Mycobacterium tuberculosis-infected nonhuman primates during both latent and active disease. In mice, we found that DCIR deficiency impairs STAT1-mediated type I IFN signaling in DCs, leading to increased production of IL-12 and increased differentiation of T lymphocytes toward Th1 during infection. As a consequence, DCIR-deficient mice control M. tuberculosis better than WT animals but also develop more inflammation characterized by an increased production of TNF and inducible NOS (iNOS) in the lungs. Altogether, our results reveal a pathway by which a C-type lectin modulates the equilibrium between infection-driven inflammation and pathogen's control through sustaining type I IFN signaling in DCs.

Targets of Neutrophil Influx and Weaponry: Therapeutic Opportunities for Chronic Obstructive Airway Disease.

Neutrophils are important effector cells of antimicrobial immunity in an acute inflammatory response, with a primary role in the clearance of extracellular pathogens. However, in respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), there is excessive infiltration and activation of neutrophils, subsequent production of reactive oxygen species, and release of serine proteases, matrix metalloproteinases, and myeloperoxidase—resulting in collateral damage as the cells infiltrate into the tissue. Increased neutrophil survival through dysregulated apoptosis facilitates continued release of neutrophil-derived mediators to perpetuate airway inflammation and tissue injury. Several target mechanisms have been investigated to address pathologic neutrophil biology and thereby provide a novel therapy for respiratory disease. These include neutrophil influx through inhibition of chemokine receptors CXCR2, CXCR1, and PI3Kγ signaling and neutrophil weaponry by protease inhibitors, targeting matrix metalloproteinases and neutrophil serine proteases. In addition, neutrophil function can be modulated using selective PI3Kδ inhibitors. This review highlights the latest advances in targeting neutrophils and their function, discusses the opportunities and risks of neutrophil inhibition, and explores how we might better develop future strategies to regulate neutrophil influx and function for respiratory diseases in dire need of novel effective therapies.

CLINICO-PATHOGENETIC VALUE OF SOME CYTOKINES IN PERIODONTITIS

Most authors ascribe pathogenesis of parodontitis to alterations of oral microbiota and mechanisms of local immunity. One may therefore assume that of the concepts of pathogenesis, diagnosis and treatment of the disease may be successfully developed when implementing immunological studies of oral fluid. The aim of present study was to characterize cytokine status of the oral fluid in patients with chronic periodontitis. The study included 101 subjects who were divided into two groups, according to results of retrospective analysis, i.e., study group (69 patients) with moderate or severe periodontitis, and control group (32 virtually healthy volunteers). In control group of patients, cytokine levels corresponded to normal values. In the patients with periodontitis, we have revealed increased IL-2, IL-4 levels. This finding suggests that the cytokine balance in periodontitis is characterized by predominance of Th2 produced factors, i.e., activation of “anti-inflammatory” immunemediated mechanisms. We have also determined VEGF levels in oral fluid, since disturbances of microcirculatory bed seem to be important in evolving periodontitis, along with immune shifts. The VEGF content in oral fluid also tended to increase in the patients. We have found that the IL-4 level in the oral fluid is of high diagnostic value in periodontitis, with diagnostic sensitivity of 88%, and diagnostic specificity of 99% (AUC = 0.95). In our study, we have obtained data corresponding to general view on altered local immune mechanisms in developing chronic periodontitis. This shift manifests as imbalance in cytokine production, especially, by activated IL-4 production. One may assume that this cytokine exerts both pathogenetic effect (immunomediated destruction of tissues) and protective action (stimulation of antimicrobial immunity) in periodontitis. Prevalence and ratio of these effects seems to determine progression rates and development of complications in the disease. Determination of IL-4 content in oral fluid can be considered a potential quantitative tool for laboratory diagnosis of periodontal tissue diseases, being a marker of activity in this pathological process.

C-type lectins facilitate tumor metastasis.

Metastasis, a life-threatening complication of cancer, leads to the majority of cases of cancer-associated mortality. Unfortunately, the underlying molecular and cellular mechanisms of cancer metastasis remain to be fully elucidated. C-type lectins are a large group of proteins, which share structurally homologous carbohydrate-recognition domains (CRDs) and possess diverse physiological functions, including inflammation and antimicrobial immunity. Accumulating evidence has demonstrated the contribution of C-type lectins in different steps of the metastatic spread of cancer. Notably, a substantial proportion of C-type lectins, including selectins, mannose receptor (MR) and liver and lymph node sinusoidal endothelial cell C-type lectin, are important molecular targets for the formation of metastases in vitro and in vivo. The present review summarizes what has been found regarding C-type lectins in the lymphatic and hematogenous metastasis of cancer. An improved understanding the role of C-type lectins in cancer metastasis provides a comprehensive perspective for further clarifying the molecular mechanisms of cancer metastasis and supports the development of novel C-type lectins-based therapies the for prevention of metastasis in certain types of cancer.

Human Vδ2 T cells are a major source of interleukin-9

Vδ2Vγ9 T cells are the dominant γδ T-cell subset in human peripheral blood. Vδ2 T cells recognize pyrophosphate molecules derived from microbes or tumor cells; hence, they play a role in antimicrobial and antitumor immunity. TGF-β, together with IL-15, induces a regulatory phenotype in Vδ2 T cells, characterized by forkhead box protein P3 (FoxP3) expression and suppressive activity on CD4 T-cell activation. We performed a genome-wide transcriptome analysis and found that the same conditions (TGF-β plus IL-15) strongly enhanced the expression of additional genes in Vδ2 T cells, including IKAROS family zinc finger 4 (IKZF4; Eos), integrin subunit alpha E (ITGAE; CD103/αEβ7), and IL9 This up-regulation was associated with potent IL-9 production as revealed by flow cytometry and multiplex analysis of cell culture supernatants. In contrast to CD4 and CD8 αβ T cells, γδ T cells did not require IL-4 for induction of intracellular IL-9 expression. Upon antigen restimulation of Vδ2 T cells expanded in vitro in the presence of TGF-β and IL-15, IL-9 was the most abundant among 16 analyzed cytokines and chemokines. IL-9 is a pleiotropic cytokine involved in various (patho)physiological conditions, including allergy and tumor defense, where it can promote antitumor immunity. Given the conspicuous sensitivity of many different tumors to Vδ2 T-cell-mediated killing, the conditions defined here for strong induction of IL-9 might be relevant for the development of Vδ2 T-cell-based immunotherapy.

RORγt, a multitask nuclear receptor at mucosal surfaces.

RORγt is a nuclear hormone receptor that has followed an exponential success carrier. Its modest origins as an orphan receptor cloned from human pancreas blossomed within 15 years into a critical regulator of anti-microbial immunity and a major target in the fight against inflammatory pathologies. Here, I review its role as a transcription factor required for the generation of type 3 lymphoid cells, which induce the development of lymphoid tissues, provide resistance of epithelial stem cells to injury, maintain homeostasis with the symbiotic microbiota, orchestrate defense against extracellular microbes, and regulate allergic responses. RORγt is also an intriguing molecule that is regulated by the circadian rhythm and includes cholesterol metabolites as ligands. RORγt therefore links anti-microbial immunity with circadian rhythms and steroids, the logic of which remains to be understood.

Molecular characterization, expression analysis, and bactericidal activity of the derivative peptides of TFPI-1 and TFPI-2 in half-smooth tongue sole, Cynoglossus semilaevis

Tissue factor pathway inhibitors (TFPIs) are Kunitz-type serine protease inhibitors that reversibly regulate the blood coagulation induced by tissue factor. TFPI family contain two members, TFPI-1 and TFPI-2. Recent studies have shown TFPI-1 and TFPI-2 also play important roles in innate immunity, however, the potential function of teleost TFPI are very limited. In this study, we characterized two TFPI (CsTFPI-1 and CsTFPI-2) molecules from half-smooth tongue sole (Cynoglossus semilaevis), examined their tissue distributions and expression patterns under pathogens stimulation as well as investigated the antibacterial activity of the C-terminal peptides. Quantitative real time RT-PCR analysis showed that constitutive CsTFPI-1 expression occurred, in increasing order, in head kidney, intestine, brain, spleen, liver, skin, gills, heart, and muscle; CsTFPI-2 was expressed, in increasing order, in the gills, intestine, skin, head kidney, liver, brain, spleen, muscle, and heart. Under Vibrio anguillarum, Streptococcus agalactiae and fish megalocytivirus stimulation, both CsTFPI-1 and CsTFPI-2 expression increased significantly in a manner that depended on the pathogen, tissue type, and infection stage, which suggested CsTFPI-1 and CsTFPI-2 play important roles in anti-bacterial and anti-viral infection. Finally, C-terminal peptides of CsTFPI-1 and CsTFPI-2, were synthesized and proved to have antibacterial effect against Micrococcus luteus that were independent of host serum. Take together, these results indicate that CsTFPI-1 and CsTFPI-2 play important roles in antimicrobial immunity of this fish.