Interleukin-35 is upregulated in response to influenza virus infection and secondary bacterial pneumonia

Investigation of IL-35 and IL-39, New Members of the IL-12 Family, in Different Clinical Presentations of Brucellosis

Brucellosis is significantly influenced by the interactions between the causative Brucella bacteria and host immunity. Recently identified cytokines have been described for their immunomodulatory effects in numerous inflammatory, autoimmune and infectious diseases. Some of them are new members of cytokine superfamilies, including several members of the IL-12 superfamily (IL-35, IL-39). The major purpose of the present study was to investigate the role of these new immunomodulatory cytokines in Brucella infections. The levels of IL-35 and IL-39 in the serum of 40 acute and 40 chronic brucellosis patients and 40 healthy controls were measured by ELISA. The mRNA levels of IL-35 and IL-39 in PBMCs were detected by RT-qPCR. Both IL-35 and IL-39 serum concentrations were significantly higher in healthy control subjects than in brucellosis patients, and IL-35 and IL-39 serum levels of chronic brucellosis patients were higher than those of acute cases. It was also found that the expression of Ebi3/IL-12A (IL-35 genes) and Ebi3/IL-23A (IL-39 genes) was upregulated in chronic brucellosis patients compared to healthy controls. Moreover, the expression of the Ebi3/IL-12A and Ebi3/IL-23A genes was lower in patients with acute brucellosis than in patients with chronic brucellosis. Overall, this study showed that IL-35 and IL-39 are positively correlated in brucellosis and significantly decreased during the disease. Significantly lower levels of IL-35 and IL-39 in acute brucellosis than in chronic brucellosis and healthy controls suggest that these cytokines may play a key role in suppressing the immune response to brucellosis and its progression to chronicity.

The interplay between SARS-CoV-2 infected airway epithelium and immune cells modulates regulatory/inflammatory signals

To assess the cross-talk between immune cells and respiratory tract during SARS-CoV-2 infection, we analyzed the relationships between the inflammatory response induced by SARS-CoV-2 replication and immune cells phenotype in a reconstituted organotypic human airway epithelium (HAE). The results indicated that immune cells failed to inhibit SARS-CoV-2 replication in the HAE model. In contrast, immune cells strongly affected the inflammatory profile induced by SARS-CoV-2 infection, dampening the production of several immunoregulatory/inflammatory signals (e.g., IL-35, IL-27, and IL-34). Moreover, these mediators were found inversely correlated with innate immune cell frequency (NK and γδ T cells) and directly with CD8 T cells. The enriched signals associated with NK and CD8 T cells highlighted the modulation of pathways induced by SARS-CoV-2 infected HAE. These findings are useful to depict the cell-cell communication mechanisms necessary to develop novel therapeutic strategies aimed to promote an effective immune response.

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HAE as a model to study the cross-talk between infected epithelium and immune cells

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Immune cells failed to inhibit SARS-CoV-2 replication

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Immune cells dampen the production of several signals induced by SARS-CoV-2 infection

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Decrease of NK/γδ T and increase of CD8 T cells in SARS-CoV-2 infected HAE co-culture

Elevated interleukin-35 suppresses liver inflammation by regulation of T helper 17 cells in acute hepatitis B virus infection

Interleukin (IL)-35 is a responsive anti-inflammatory cytokine implicated in different diseases processes. It has been reported that elevated IL-35 contributed to immunosuppression in chronic hepatitis by modulation of T helper 17 (Th17) and regulatory T cells. However, the role of IL-35 in acute hepatitis B (AHB) was still not completely elucidated. Thus, in the present study, we analyzed the expression and regulatory activity of IL-35 to Th17 cells and inflammatory response during acute hepatitis B virus (HBV) infection in both peripheral blood cells isolated from AHB patients and in hydrodynamic induced HBV-infected mouse model. Plasma IL-35 level and circulating HBV peptides-induced Th17 frequency was significantly elevated in AHB patients, and IL-35 expression negatively correlated with liver inflammation. In vitro IL-35 stimulation to CD4+ T cells purified from AHB patients down-regulated HBV peptides-induced Th17-phenotype, which presented as reduced IL-17 and IL-22 production. In vivo IL-35 administration dampened liver inflammation in HBV plasmid injected mice, however, did not affect HBV antigens production. This process was accompanied by suppression of natural killer cells and down-regulation of HBV peptides-induced Th17 cells in the liver, but did not affect total intrahepatic lymphocytes and other cell subsets numbers or chemokines expression in the liver. In conclusion, the current data indicated that IL-35 might be a novel mediator associated with hepatocytes damage and liver inflammation by regulating HBV peptides-induced Th17 cells during acute HBV infection. The potential anti-inflammatory property of IL-35 might be pivotal for developing new therapeutic approaches for hepatitis B.

Regulatory cytokine function in the respiratory tract

The respiratory tract is an important site of immune regulation; required to allow protective immunity against pathogens, while minimizing tissue damage and avoiding aberrant inflammatory responses to inhaled allergens. Several cell types work in concert to control pulmonary immune responses and maintain tolerance in the respiratory tract, including regulatory and effector T cells, airway and interstitial macrophages, dendritic cells and the airway epithelium. The cytokines transforming growth factor β, interleukin (IL-) 10, IL-27, and IL-35 are key coordinators of immune regulation in tissues such as the lung. Here, we discuss the role of these cytokines during respiratory infection and allergic airway disease, highlighting the critical importance of cellular source and immunological context for the effects of these cytokines in vivo.

IL-35 expression in hepatocellular carcinoma cells is associated with tumor progression

IL-35 has recently been demonstrated to play significant roles in the progression of various malignant tumors. We investigated the expression of IL-35 in hepatocellular carcinoma (HCC) and the regulatory mechanisms in HCC progression. Tissue microarray from 75 HCC patients revealed that IL-35 was primarily localized in the cytoplasm of cancer cells and peri-tumoral hepatocytes. Quantitative analysis showed that IL-35 expression was significantly lower in patients in the advanced stages than in the early stages. Significantly lower expression of IL-35 was also observed in HCC patients with higher histological grades, larger tumor size, positive microvascular invasion and lymph node/distant metastasis. IL-35 over-expression in HepG2 cells significantly upregulated HLA-ABC and CD95, reduced activities of MMP-2 and MMP-9, and decreased cell migration, invasion and colony formation capacities. Our data indicated that decreased expression of IL-35 in tumor tissues might contribute to the progression of HCC, and IL-35 may serve as a new therapeutic target for HCC.

Interleukin-35 Level Is Elevated in Patients with Chronic Hepatitis B Virus Infection

Backgrounds: As one of the major public health problems, the hepatitis B virus (HBV) infection would activate the immune system. The outcome of HBV infection was affect significantly by the interactions between HBV and host immune response. Interleukins play important role in anti-viral immunity. Here we investigated the role of interleukin-35 (IL-35) in chronic HBV infection patients. Methods/Results: Serum IL-35 in 72 chronic hepatitis B virus infection patients and 41 healthy control subjects were analyzed by ELISA assay. The mRNA level of IL-35 in PBMCs was determined by RT-qPCR. In this study, we found that both protein and mRNA levels of IL-35 were significantly decreased in chronic HBV patients compared to the healthy controls. Furthermore, the statistical analysis found that serum IL-35 was significantly associated with HBV DNA (P =0.0158), ALT (P =0.0003), AST (P =0.0216), TB (P =0.0270) and AFP (P =0.0369). Importantly, correlation analysis also found that serum IL-35 level was negatively correlated with HBV DNA copies, ALT, AST, TB and AFP. Meanwhile, IL-35 treatment inhibited the level of HBV DNA, HBsAg and HBeAg in HepAD38 cells. Conclusion: Our study identified that IL-35 may be a novel marker associated with HBV infection and hepatocytes injury. These data suggested the potential use of IL-35 in the HBV treatment.

Interleukin-35 Modulates the Imbalance Between Regulatory T Cells and T Helper 17 Cells in Enterovirus 71-Induced Hand, Foot, and Mouth Disease

Interleukin (IL)-35 modulates the imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, which played vital roles in the pathogenesis of autoimmune and infectious diseases. However, the role of Tregs/Th17 cell imbalance and the regulatory functions of IL-35 have remained largely unknown in enterovirus 71 (EV71)-induced hand, foot, and mouth disease (HFMD). In this study, a total of 47 HFMD patients (30 with mild HFMD and 17 with severe HFMD) and 13 healthy individuals were enrolled. The frequencies of CD4⁺CD25⁺CD127^dim/- Tregs and CD4⁺IL-17⁺ Th17 cells, as well as IL-35 expression levels, were measured. Cellular proliferation and cytokine production was also determined in purified Tregs following recombinant IL-35 stimulation. An imbalance between Tregs and Th17 cells was observed in children with severe HFMD, which manifested as a reduction in the Tregs population and an elevation in the Th17 population. Serum IL-35 concentrations were also decreased in case of severe HFMD, which correlated with the Tregs:Th17 cell ratios. Recombinant IL-35 stimulation increased the proportion of Tregs, but downregulated that of Th17 cells. Treatment with IL-35 enhanced Tregs suppressive function and IL-35 and IL-10 expression, but reduced IL-22 secretion in both healthy individuals and those with severe HFMD. The Tregs:Th17 cell ratio was increased in the convalescent patients, however, a significant reduction in serum IL-35 was not observed. Our findings indicated that EV71 infection shifted the Tregs:Th17 cell ratio through IL-35 by downregulating inhibitory cytokine production and reducing the cell-to-cell contact inhibition of effector T cells. Regulation of IL-35 as it relates to the Tregs/Th17 balance may play a critical role in the pathogenesis of EV71-associated HFMD.

Interleukin-35 Suppresses Antiviral Immune Response in Chronic Hepatitis B Virus Infection

The mechanisms of hepatitis B virus (HBV) persistent infection are not completely understood. Interleukin (IL)-35, which is a newly identified cytokine belongs to IL-12 family, has been demonstrated to induce immunotolerance. Thus, the aim of current study was to investigate the role of IL-35 during chronic HBV infection. A total of 61 patients with chronic HBV infection [37 chronic hepatitis B (CHB) and 24 asymptomatic HBV carriers (ASC)] and 20 healthy individuals were enrolled. IL-35 concentration as well as the modulatory function of IL-35 on CD4⁺CD25⁺CD127^dim/− regulatory T cells (Tregs) and on HBV antigen-specific CD8⁺ T cells was investigated. IL-35 expression was significantly increased in both CHB and ASC, and was positively correlated with the levels of HBV DNA. Inhibition of viral replication induced the reduction in serum levels of IL-35. IL-35 stimulation led to inhibition of proinflammatory cytokine productions and elevation of apoptosis in peripheral blood mononuclear cells (PBMCs), but not in HepG2.2.15 cells. Moreover, IL-35 stimulation not only robustly inhibited cellular proliferation, but also up-regulated the production of IL-10 and IL-35 in a HBV antigen-specific and non-specific manner in Tregs/CD4⁺CD25⁻ T cells coculture system, which indicated enhancement of suppressive function of Tregs. Furthermore, IL-35 also reduced both cytolytic activity (direct lysis of HepG2.2.15 cells) and noncytolytic function (IFN-γ and TNF-α production) of HBV antigen-specific CD8⁺ T cells. The current data suggested that IL-35 contributed to maintain viral persistence by suppressing antiviral immune responses and reducing inflammatory responses in chronic HBV infection.

Peptidoglycan from Immunobiotic Lactobacillus rhamnosus Improves Resistance of Infant Mice to Respiratory Syncytial Viral Infection and Secondary Pneumococcal Pneumonia

Several research works have demonstrated that beneficial microbes with the capacity to modulate the mucosal immune system (immunobiotics) are an interesting alternative to improve the outcome of bacterial and viral respiratory infections. Among the immunobiotic strains with the capacity to beneficially modulate respiratory immunity, Lactobacillus rhamnosus CRL1505 has outstanding properties. Although we have significantly advanced in demonstrating the capacity of L. rhamnosus CRL1505 to improve resistance against respiratory infections as well as in the cellular and molecular mechanisms involved in its beneficial activities, the potential protective ability of this strain or its immunomodulatory cellular fractions in the context of a secondary bacterial pneumonia has not been addressed before. In this work, we demonstrated that the nasal priming with non-viable L. rhamnosus CRL1505 or its purified peptidoglycan differentially modulated the respiratory innate antiviral immune response triggered by toll-like receptor 3 activation in infant mice, improving the resistance to primary respiratory syncytial virus (RSV) infection, and secondary pneumococcal pneumonia. In association with the protection against RSV-pneumococcal superinfection, we found that peptidoglycan from L. rhamnosus CRL1505 significantly improved lung CD3⁺CD4⁺IFN-γ⁺, and CD3⁺CD4⁺IL-10⁺ T cells as well as CD11c⁺SiglecF⁺IFN-β⁺ alveolar macrophages with the consequent increases of IFN-γ, IL-10, and IFN-β in the respiratory tract. Our results also showed that the increase of these three cytokines is necessary to achieve protection against respiratory superinfection since each of them are involved in different aspect of the secondary pneumococcal pneumonia that have to be controlled in order to reduce the severity of the infectious disease: lung pneumococcal colonization, bacteremia, and inflammatory-mediated lung tissue injury.

An immunosuppressive function of interleukin-35 in chronic hepatitis C virus infection

Interleukin (IL)-35, a newly identified member of the IL-12 cytokine family, has been reported to suppress inflammation and induce immunotolerance. However, little is known regarding the role of IL-35 during chronic hepatitis C virus (HCV) infection. Herein, we measured the serum IL-35 concentration of 73 patients with hepatitis C and 22 healthy individuals, as well as further investigated the modulatory function of IL-35 on CD4⁺CD25⁺CD127^dim/- regulatory T cells (Tregs) and on hepatocytes infected with HCV in cell culture (HCVcc). IL-35 expression was significantly increased in patients with chronic hepatitis C and was positively correlated with the levels of HCV RNA. Inhibition of viral replication led to decreases in the serum levels of IL-35. IL-35 stimulation not only elevated the percentage of Tregs but also robustly inhibited cellular proliferation and up-regulated the production of anti-inflammatory cytokines (e.g., IL-10 and IL-35) in a HCV-specific and non-specific manner, which indicates enhancement of the suppressive function of Tregs. Although IL-35 did not exert anti-HCV activity in HCVcc-infected Huh7.5 cells, it reduced inflammatory cytokine secretion from Huh7.5 cells. This was probably via inhibition of the STAT1 and STAT3 signaling pathways, which could suppress subsequent liver damage due to chronic hepatitis C. The current data suggested that IL-35 contributes to persistent HCV infection by inhibiting antiviral immune activity. Moreover, IL-35 might also protect against HCV-induced liver injury by down-regulating the expression of proinflammatory cytokines. Thus, the immunosuppressive properties of IL-35 might play contradictory roles in maintaining viral persistence and reducing the inflammatory responses in chronic HCV infection.

Plasma Level of Interleukin-35 as an Independent Prognostic Indicator in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma is a major type of liver cancer with poor prognosis.

AIM

The aim of the study was to determine the prognostic significance of plasma interleukin-35 level in hepatocellular carcinoma.

METHODS

A total of 153 hepatocellular carcinoma patients and 153 healthy controls were enrolled. Blood samples were obtained at admission. Plasma interleukin-35 level was analyzed by enzyme-linked immunosorbent assay. Distribution of T cell subset and expression of Fas/FasL protein were detected by flow cytometry. The patients were followed up for 2 years. Poor prognosis was defined as death of hepatocellular carcinoma.

RESULTS

The plasma levels of interleukin-35 were significantly higher in the patients than the controls (25.1 ± 13.1, 9.3 ± 6.3 pg/mL, P < 0.001). After adjusted for multiple confounding factors, the multivariate logistic regression analyses reported that high level of interleukin-35 (≥25.0 pg/mL) was associated with the poor prognosis in the patients (OR 6.63, 95 % CI 3.27-13.47). Compared with the patients with low level of interleukin-35 (<25.0 pg/mL), the patients with high level of interleukin-35 showed higher frequencies of CD4+CD25+FoxP3+ and CD3+Foxp3+ regulatory T cells (P < 0.001 and P < 0.001) and also showed higher apoptosis levels of CD8+ T cells (P < 0.001).

CONCLUSION

Circulating interleukin-35 concentration might be an independent prognostic indicator in hepatocellular carcinoma. Such prognostic significance could be partly involved in the activation of regulatory T cell and the apoptosis of CD8+ T cell.

Immune Responses to Influenza Virus and Its Correlation to Age and Inherited Factors

Influenza viruses belong to the family Orthomyxoviridae of enveloped viruses and are an important cause of respiratory infections worldwide. The influenza virus is able to infect a wide variety species as diverse as poultry, marine, pigs, horses, and humans. Upon infection with influenza virus the innate immunity plays a critical role in efficient and rapid control of viral infections as well as in adaptive immunity initiation. The humoral immune system produces antibodies against different influenza antigens, of which the HA-specific antibody is the most important for neutralization of the virus and thus prevention of illness. Cell mediated immunity including CD4+ helper T cells and CD8+ cytotoxic T cells are the other arms of adaptive immunity induced upon influenza virus infection. The complex inherited factors and age related changes are associated with the host immune responses. Here, we review the different components of immune responses against influenza virus. Additionally, the correlation of the immune response to age and inherited factors has been discussed. These determinations lead to a better understanding of the limitations of immune responses for developing improved vaccines to control influenza virus infection.

Interleukin 35: A novel candidate biomarker to diagnose early onset sepsis in neonates

BACKGROUND

Early onset sepsis (EOS) remains a major cause of morbidity and mortality in newborns; however, current diagnostic tools are inadequate. We evaluated the accuracy of a novel cytokine, interleukin (IL)-35, for the diagnosis of EOS in comparison with other infection markers.

METHODS

One hundred fifty-seven neonates with suspected sepsis in the first 3days of life were enrolled in this perspective study. All enrolled patients were divided into infected group and unlikely infected group according to clinical data. IL-35, C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and blood culture were measured once the suspected EOS was documented.

RESULTS

Serum concentration of IL-35 was increased significantly in the infected group compared with the unlikely infected group (median 36.4 versus 27.1pg/ml, respectively, p<0.001). The area under receiver-operating characteristic (ROC) curve were 0.756 for IL-35, 0.713 for PCT (age-adjusted), 0.670 for CRP, and 0.619 for WBC. With a cut-off value of 31.7pg/ml, the diagnostic sensitivity and specificity of IL-35 were 78.48% and 66.67%, respectively. Moreover, unlike PCT concentration, IL-35 concentration did not fluctuate in neonates who were unlikely to be infected (p=0.885).

CONCLUSION

The diagnostic performance of IL-35 was superior to that of PCT and other commonly used markers, suggesting that IL-35 may be a valuable tool for EOS diagnosis.

Role of Autophagy and Apoptosis in the Postinfluenza Bacterial Pneumonia

The risk of influenza A virus (IAV) is more likely caused by secondary bacterial infections. During the past decades, a great amount of studies have been conducted on increased morbidity from secondary bacterial infections following influenza and provide an increasing number of explanations for the mechanisms underlying the infections. In this paper, we first review the recent research progress that IAV infection increased susceptibility to bacterial infection. We then propose an assumption that autophagy and apoptosis manipulation are beneficial to antagonize post-IAV bacterial infection and discuss the clinical significance.