Role of IL-17A and IL-10 in the antigen induced inflammation model by Mycoplasma pneumoniae

Varying conjunctival immune response adaptations of house finch populations to a rapidly evolving bacterial pathogen

Pathogen adaptations during host-pathogen co-evolution can cause the host balance between immunity and immunopathology to rapidly shift. However, little is known in natural disease systems about the immunological pathways optimised through the trade-off between immunity and self-damage. The evolutionary interaction between the conjunctival bacterial infection Mycoplasma gallisepticum (MG) and its avian host, the house finch (Haemorhous mexicanus), can provide insights into such adaptations in immune regulation. Here we use experimental infections to reveal immune variation in conjunctival tissue for house finches captured from four distinct populations differing in the length of their co-evolutionary histories with MG and their disease tolerance (defined as disease severity per pathogen load) in controlled infection studies. To differentiate contributions of host versus pathogen evolution, we compared house finch responses to one of two MG isolates: the original VA1994 isolate and a more evolutionarily derived one, VA2013. To identify differential gene expression involved in initiation of the immune response to MG, we performed 3'-end transcriptomic sequencing (QuantSeq) of samples from the infection site, conjunctiva, collected 3-days post-infection. In response to MG, we observed an increase in general pro-inflammatory signalling, as well as T-cell activation and IL17 pathway differentiation, associated with a decrease in the IL12/IL23 pathway signalling. The immune response was stronger in response to the evolutionarily derived MG isolate compared to the original one, consistent with known increases in MG virulence over time. The host populations differed namely in pre-activation immune gene expression, suggesting population-specific adaptations. Compared to other populations, finches from Virginia, which have the longest co-evolutionary history with MG, showed significantly higher expression of anti-inflammatory genes and Th1 mediators. This may explain the evolution of disease tolerance to MG infection in VA birds. We also show a potential modulating role of BCL10, a positive B- and T-cell regulator activating the NFKB signalling. Our results illuminate potential mechanisms of house finch adaptation to MG-induced immunopathology, contributing to understanding of the host evolutionary responses to pathogen-driven shifts in immunity-immunopathology trade-offs.

Regulatory T cells in lung disease and transplantation

Pulmonary disease can refer to the disease of the lung itself or the pulmonary manifestations of systemic diseases, which are often connected to the malfunction of the immune system. Regulatory T (Treg) cells have been shown to be important in maintaining immune homeostasis and preventing inflammatory damage, including lung diseases. Given the increasing amount of evidence linking Treg cells to various pulmonary conditions, Treg cells might serve as a therapeutic strategy for the treatment of lung diseases and potentially promote lung transplant tolerance. The most potent and well-defined Treg cells are Foxp3-expressing CD4+ Treg cells, which contribute to the prevention of autoimmune lung diseases and the promotion of lung transplant rejection. The protective mechanisms of Treg cells in lung disease and transplantation involve multiple immune suppression mechanisms. This review summarizes the development, phenotype and function of CD4+Foxp3+ Treg cells. Then, we focus on the therapeutic potential of Treg cells in preventing lung disease and limiting lung transplant rejection. Furthermore, we discussed the possibility of Treg cell utilization in clinical applications. This will provide an overview of current research advances in Treg cells and their relevant application in clinics.

Unveiling the stealthy tactics: mycoplasma's immune evasion strategies

Mycoplasmas, the smallest known self-replicating organisms, possess a simple structure, lack a cell wall, and have limited metabolic pathways. They are responsible for causing acute or chronic infections in humans and animals, with a significant number of species exhibiting pathogenicity. Although the innate and adaptive immune responses can effectively combat this pathogen, mycoplasmas are capable of persisting in the host, indicating that the immune system fails to eliminate them completely. Recent studies have shed light on the intricate and sophisticated defense mechanisms developed by mycoplasmas during their long-term co-evolution with the host. These evasion strategies encompass various tactics, including invasion, biofilm formation, and modulation of immune responses, such as inhibition of immune cell activity, suppression of immune cell function, and resistance against immune molecules. Additionally, antigen variation and molecular mimicry are also crucial immune evasion strategies. This review comprehensively summarizes the evasion mechanisms employed by mycoplasmas, providing valuable insights into the pathogenesis of mycoplasma infections.

The Double Game Played by Th17 Cells in Infection: Host Defense and Immunopathology

T-helper 17 (Th17) cells represent a subpopulation of CD4+ T lymphocytes that play an essential role in defense against pathogens. Th17 cells are distinguished from Th1 and Th2 cells by their ability to produce members of the interleukin-17 (IL-17) family, namely IL-17A and IL-17F. IL-17 in turn induces several target cells to synthesize and release cytokines, chemokines, and metalloproteinases, thereby amplifying the inflammatory cascade. Th17 cells reside predominantly in the lamina propria of the mucosa. Their main physiological function is to maintain the integrity of the mucosal barrier against the aggression of infectious agents. However, in an appropriate inflammatory microenvironment, Th17 cells can transform into immunopathogenic cells, giving rise to inflammatory and autoimmune diseases. This review aims to analyze the complex mechanisms through which the interaction between Th17 and pathogens can be on the one hand favorable to the host by protecting it from infectious agents, and on the other hand harmful, potentially generating autoimmune reactions and tissue damage.

B cells oppose Mycoplasma pneumoniae vaccine enhanced disease and limit bacterial colonization of the lungs

Development of an effective vaccine for Mycoplasma pneumoniae has been hindered by reports of Vaccine Enhanced Disease (VED) in test subjects vaccinated and challenged in studies conducted in the 1960s. The exact mechanism of disease exacerbation has yet to be fully described, but host immune responses to Lipid-Associated Membrane Proteins (LAMPs) lipoprotein lipid moieties have been implicated. LAMPs-induced exacerbation appears to involve helper T cell recall responses, due in part to their influence on neutrophil recruitment and subsequent inflammatory responses in the lung. Herein, we characterized the functions of host B cell responses to M. pneumoniae LAMPs and delipidated-LAMPs (dLAMPs) by conducting passive transfer and B cell depletion studies to assess their contribution to disease exacerbation or protection using a BALB/c mouse model. We found that antibody responses to M. pneumoniae LAMPs and dLAMPs differ in magnitude, but not in isotype or subclass. Passive transfer, dLAMP denaturation, and monoclonal antibody studies indicate that antibodies do not cause VED, but do appear to contribute to control of bacterial loads in the lungs. Depletion of B cells prior to LAMPs-vaccination results in significantly enhanced pathology in comparison to B cell competent controls, suggesting a possible regulatory role of B cells distinct from antibody secretion. Taken together, our findings suggest that B cell antibody responses to M. pneumoniae contribute to, but are insufficient for protection against challenge on their own, and that other functional properties of B cells are necessary to limit exacerbation of disease in LAMPs-vaccinated mice after infection.

Tracheal cellular immune response in chickens inoculated with Mycoplasma synoviae vaccine, MS-H or its parent strain 86079/7NS

Mycoplasma synoviae causes respiratory tract disease in chickens characterised by mild to moderate lymphoplasmacytic infiltration of the tracheal mucosa. MS-H (Vaxsafe1 MS, Bioproperties Pty Ltd.) is an effective live attenuated vaccine for M. synoviae, but the immunological basis for its mechanism of protection has not been investigated, and the phenotypes of lymphocytes and associated cytokines involved in the local adaptive immune response have not been described previously. In this study, specific-pathogen-free chickens were inoculated intra-ocularly at 3 weeks of age with either M. synoviae vaccine strain MS-H or vaccine parent strain 86079/7NS (7NS), or remained uninoculated. At 2-, 7- and 21 days post-inoculation (dpi), tracheal mucosal pathology, infiltrating lymphocytes subsets and transcription levels of mRNA encoding 8 cytokines were assessed using light microscopy, indirect immunofluorescent staining and RT-qPCR, respectively. After inoculation, tracheal mucosal thickness, tracheal mucosal lesions, and numbers of infiltrating CD4⁺CD25^- cells, B-cells, and macrophages were greater in MS-H- and 7NS-inoculated chickens compared with non-inoculated. Inoculation with 7NS induced up-regulation of IFN-γ, while vaccination with MS-H induced up-regulation of IL-17A, when compared with non-inoculated birds. Both inoculated groups had a moderate infiltrate of CD4⁺CD25⁺ T cells in the tracheal mucosa. These findings reveal that the tracheal local cellular response after MS-H inoculation is dominated by a Th-17 response, while that of 7NS-inoculated chickens is dominated by a Th-1 type response.

Mycoplasma pneumoniae Compared to Streptococcus pneumoniae Avoids Induction of Proinflammatory Epithelial Cell Responses despite Robustly Inducing TLR2 Signaling

Mycoplasma pneumoniae and Streptococcus pneumoniae are the most common bacterial causes of pneumonia in children. The clinical characteristics of pneumonia differ significantly between the two bacteria. We aimed to elucidate the differences in pathogenesis between M. pneumoniae and S. pneumoniae by characterizing the respiratory epithelial cell immune response to both pathogens. Using primary human bronchial epithelial cells in air-liquid interface cultures, we observed lower production of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in response to M. pneumoniae than to S. pneumoniae. In contrast to the differences in proinflammatory cytokine production, Toll-like receptor 2 (TLR2)-mediated signaling in response to M. pneumoniae was stronger than to S. pneumoniae. This difference largely depended on TLR1 and not TLR6. We found that M. pneumoniae, but not S. pneumoniae, also induced signaling of TLR10, a coreceptor of TLR2 that has inhibitory properties. M. pneumoniae-induced TLR10 signaling on airway epithelial cells was partially responsible for low IL-8 production, as blocking TLR10 by specific antibodies increased cytokine production. M. pneumoniae maintained Th2-associated cytokine production by epithelial cells, which concurs with the known association of M. pneumoniae infection with asthma. M. pneumoniae left IL-33 levels unchanged, whereas S. pneumoniae downregulated IL-33 production both under homeostatic and Th2-promoting conditions. By directly comparing M. pneumoniae and S. pneumoniae, we demonstrate that M. pneumoniae avoids induction of proinflammatory cytokine response despite its ability to induce robust TLR2 signaling. Our new findings suggest that this apparent paradox may be partially explained by M. pneumoniae-induced signaling of TLR2/TLR10.

Pinocembrin Relieves Mycoplasma pneumoniae Infection‑Induced Pneumonia in Mice Through the Inhibition of Oxidative Stress and Inflammatory Response

Pneumonia is a serious infectious disease with increased morbidity and mortality worldwide. The M. pneumoniae is a major airway pathogen that mainly affects respiratory tract and ultimately leads to the development of pneumonia. The current exploration was aimed to uncover the beneficial properties of pinocembrin against the M. pneumoniae-triggered pneumonia in mice via its anti-inflammatory property. The pneumonia was stimulated to the BALB/c mice via infecting them with M. pneumoniae (100 µl) for 2 days through nasal drops and concomitantly treated with pinocembrin (10 mg/kg) for 3 days. The azithromycin (100 mg/kg) was used as a standard drug. Then the lung weight, nitric oxide, and myeloperoxidase (MPO) activity was assessed. The content of MDA, GSH, and SOD activity was scrutinized using kits. The total cells and DNA amount present in the bronchoalveolar lavage fluid (BALF) was assessed by standard methods. The IL-1, IL-6, IL-8, TNF-α, and TGF contents in the BALF samples and NF-κB level in the lung tissues were assessed using kits. The lung histopathology was assessed microscopically to detect the histological alterations. The 10 mg/kg of pinocembrin treatment substantially decreased the lung weight, nitric oxide (NO) level, and MPO activity. The MDA level was decreased, and GSH content and SOD activity were improved by the pinocembrin treatment. The pinocembrin administered pneumonia animals also demonstrated the decreased total cells, DNA amount, IL-1, IL-6, IL-8, TNF-α, and TGF in the BALF and NF-κB level. The findings of histological studies also witnessed the beneficial role of pinocembrin against M. pneumoniae-infected pneumonia. In conclusion, our findings confirmed that the pinocembrin effectively ameliorated the M. pneumoniae-provoked inflammation and oxidative stress in the pneumonia mice model. Hence, it could be a hopeful therapeutic agent to treat the pneumonia in the future.

Vaccination with Mycoplasma pneumoniae membrane lipoproteins induces IL-17A driven neutrophilia that mediates Vaccine-Enhanced Disease

Bacterial lipoproteins are an often-underappreciated class of microbe-associated molecular patterns with potent immunomodulatory activity. We previously reported that vaccination of BALB/c mice with Mycoplasma pneumoniae (Mp) lipid-associated membrane proteins (LAMPs) resulted in lipoprotein-dependent vaccine enhanced disease after challenge with virulent Mp, though the immune responses underpinning this phenomenon remain poorly understood. Herein, we report that lipoprotein-induced VED in a mouse model is associated with elevated inflammatory cytokines TNF-α, IL-1β, IL-6, IL-17A, and KC in lung lavage fluid and with suppurative pneumonia marked by exuberant neutrophilia in the pulmonary parenchyma. Whole-lung-digest flow cytometry and RNAScope analysis identified multiple cellular sources for IL-17A, and the numbers of IL-17A producing cells were increased in LAMPs-vaccinated/Mp-challenged animals compared to controls. Specific IL-17A or neutrophil depletion reduced disease severity in our VED model—indicating that Mp lipoproteins induce VED in an IL-17A-dependent manner and through exuberant neutrophil recruitment. IL-17A neutralization reduced levels of TNF-α, IL-1β, IL-6, and KC, indicating that IL-17A preceded other inflammatory cytokines. Surprisingly, we found that IL-17A neutralization impaired bacterial clearance, while neutrophil depletion improved it—indicating that, while IL-17A appears to confer both maladaptive and protective responses, neutrophils play an entirely maladaptive role in VED. Given that lipoproteins are found in virtually all bacteria, the potential for lipoprotein-mediated maladaptive inflammatory responses should be taken into consideration when developing vaccines against bacterial pathogens.

Kukoamine A Improves Mycoplasma pneumoniae Pneumonia by Regulating miR-222-3p/Superoxide Dismutase 2

Mycoplasma pneumoniae pneumonia (MPP) represents a common respiratory disease in children patients. Kukoamine A (KuA) is a spermine alkaloid found in the Chinese herb Cortex Lycii radices, which has a variety of pharmacological properties. However, no study has been reported on the role of KuA in MPP. Exosomes, a type of lipid bilayer-enclosed extracellular vesicles, can be delivered to the target cells, where they regulate function and physiology. With the use of human alveolar basal epithelial cells (HABECs) as an in vitro model, in this study, we sought to characterize the changes in levels of superoxide dismutase 2 (SOD2) and proinflammatory cytokines including IL-6 and TNF-α in HABECs in response to exosomes, which were isolated from peripheral blood serum of MPP patients. We found that, compared to normal, MPP patients exhibited a significant up-regulated miR-222-3p. Further, exosomal miR-222-3p downregulated SOD2 activity but promoted nuclear NF-κB activity and expression of IL-6 and TNF-α in HABECs, ultimately leading to an oxidative stress condition. Interestingly, such stimulating effects were attenuated by the pretreatment of KuA. This study suggests a critical role possessed by KuA in MPP by regulating the miR-222-3p/SOD2 axis, which represents a promising strategy for the treatment of MPP.

Development of a Nomogram for Predicting Refractory Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

In children, refractory Mycoplasma pneumoniae pneumonia (RMPP) may result in severe complications and high medical costs. There is research on a simple and easy-to-use nomogram for early prediction and timely treatment of RMPP.

METHODS

From December 2018 to June 2021, we retrospectively reviewed medical records of 299 children with Mycoplasma pneumoniae pneumonia (MPP) hospitalized in Tianjin Children's Hospital. According to their clinical manifestations, patients were divided into the RMPP group and the general Mycoplasma pneumoniae pneumonia (GMPP) group. The clinical manifestations, laboratory indicators, and radiological data of the two groups were obtained. Stepwise regression was employed for variable selection of RMPP. The predictive factors selected were used to construct a prediction model which presented with a nomogram. The performance of the prediction model was evaluated by C statistics, calibration curve, and receiver operating characteristic (ROC) curve.

RESULTS

The RMPP group significantly showed a higher proportion of females, longer fever duration, and longer hospital stay than the GMPP group (P < 0.05). Additionally, the RMPP group revealed severe clinical characteristics, including higher incidences of extrapulmonary complications, decreased breath sounds, unilateral pulmonary consolidation >2/3, and plastic bronchitis than the GMPP group (P < 0.05). The RMPP group had higher neutrophil ratio (N%), C-reactive protein (CRP), interleukin-6 (IL-6), lactic dehydrogenase (LDH), and D-dimer than the GMPP group (P < 0.05). Stepwise regression demonstrated that CRP [OR = 1.075 (95% CI: 1.020-1.133), P < 0.001], LDH [OR = 1.015 (95% CI: 1.010-1.020), P < 0.001], and D-dimer [OR = 70.94 (95% CI: 23.861-210.904), P < 0.001] were predictive factors for RMPP, and developed a prediction model of RMPP, which can be visualized and accurately quantified using a nomogram. The nomogram showed good discrimination and calibration. The area under the ROC curve of the nomogram was 0.881, 95% CI (0.843, 0.918) in training cohorts and 0.777, 95% CI (0.661, 0.893) in validation cohorts, respectively.

CONCLUSION

C-reactive protein, LDH, and D-dimer were predictive factors for RMPP. The simple and easy-to-use nomogram assisted us in quantifying the risk for predicting RMPP, and more accurately and conveniently guiding clinicians to recognize RMPP, and contribute to a rational therapeutic choice.

Absence of Association between Previous Mycoplasma pneumoniae Infection and Subsequent Myasthenia Gravis: A Nationwide Population-Based Matched Cohort Study

Mycoplasma pneumoniae (M. pneumoniae) is not only one of the most common pathogenic bacteria for respiratory infection but also a trigger for many autoimmune diseases. Its infection process shared many similarities with the pathogenesis of myasthenia gravis (MG) at cellular and cytokine levels. Recent case reports demonstrated patients present with MG after M. pneumoniae infection. However, no epidemiological studies ever looked into the association between the two. Our study aimed to investigate the relationship between M. pneumoniae infection and subsequent development of MG. In this population-based retrospective cohort study, the risk of MG was analyzed in patients who were newly diagnosed with M. pneumoniae infection between 2000 and 2013. A total of 2428 M. pneumoniae patients were included and matched with the non-M. pneumoniae control cohort at a 1:4 ratio by age, sex, and index date. Cox proportional hazards regression analysis was applied to analyze the risk of MG development after adjusting for sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The incidence rates of MG in the non-M. pneumoniae and M. pneumoniae cohorts were 0.96 and 1.97 per 10,000 person-years, respectively. Another case-control study of patients with MG (n = 515) was conducted to analyze the impact of M. pneumoniae on MG occurrence as a sensitivity analysis. The analysis yielded consistent absence of a link between M. pneumoniae and MG. Although previous studies have reported that M. pneumoniae infection and MG may share associated immunologic pathways, we found no statistical significance between M. pneumoniae infection and subsequent development of MG in this study.

β-Caryophyllene ameliorates the Mycoplasmal pneumonia through the inhibition of NF-κB signal transduction in mice

Background

Pneumonia is a frequent infectious disease that mainly affects the children and the global death rate is nearly 19% among children at the below 5 age. β-caryophyllene is an active compound, mainly occurs in the spices and it possesses immense biological activities.

Objective

This investigation deliberated to scrutinize the beneficial actions of β-caryophyllene against the M. pneumoniae induced pneumonia.

Methods

The pneumonia was stimulated to the BALB/c mice by infecting them with 100 µl of M. pneumonia for 2 days via nasal drops with the concomitant treatment with 20 mg/kg of β-caryophyllene. The total cells in the BALF of test mice were counted by using the Neuber chamber. The total protein and the pro-inflammatory cytokines status were examined by using the commercial ELISA kits. The PCR technique was used to measure the M. pneumoniae bacterial load. The NF-ƙB expression was investigated using western blotting. The lung tissues were analyzed microscopically.

Results

The β-caryophyllene notably diminished the total protein status, total cell count, and bacterial load in the pneumonia provoked mice. The marked reduction in the status of pro-inflammatory regulators was seen in the β-caryophyllene supplemented pneumonia mice. β-caryophyllene also down-regulated the expression of NF-ƙB thereby reduced the lung inflammation and tissue damages as seen in the result of histological analysis.

Conclusion

These findings were confirmed the therapeutic potential of β-caryophyllene against the M. pneumoniae-activated pneumonia in animals.

Biological functions of IL-17-producing cells in mycoplasma respiratory infection

Mycoplasmas are the smallest and simplest bacteria that lack a cell wall but have the capability of self-replication. Among them, Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia. The hallmark of mycoplasma respiratory diseases is the persistence of lung inflammation that involves both innate and adaptive immune responses. In recent years, a growing body of evidence demonstrates that IL-17 plays an important role in respiratory mycoplasma infection, and associates with the pathologic outcomes of infection, such as pneumonitis and asthma. Numerous studies have shown that a variety of cells, in particular Th17 cells, in the lung can secrete IL-17 during respiratory mycoplasma infection. In this article, we review the biological functions of distinct IL-17-producing cells in mycoplasma respiratory infection with a focus on the effect of IL-17 on the outcomes of infection.

Immunological Features of Pediatric Interstitial Pneumonia Due to Mycoplasma pneumoniae

Background: Inflammatory response, oxidative stress, and immunologic mechanism are involved in the pathogenesis of Mycoplasma pneumoniae pneumonia (MPP). However, the role of immune system of pediatric interstitial pneumonia due to M. pneumoniae infections remains poorly understood. The aim of this study was to analyze the immunologic features of pediatric interstitial pneumonia due to Mycoplasma pneumoniae (M. pneumoniae). Methods: A retrospective study was conducted on a primary cohort of children with MPP. Propensity score analysis was performed to match interstitial pneumonia and pulmonary consolidation children. Results: The clinical characteristics strongly associated with the development of interstitial pneumonia were boys, age >5 years, wheezing history, hydrothorax free, lymphocytes (>3.0 × 10⁹/L), CD19⁺ (>0.9 × 10⁹/L), CD3⁺ (>2.5 × 10⁹/L), CD4⁺ (>1.5 × 10⁹/L), CD8⁺ (>0.9 × 10⁹/L), interleukin-6 (IL-6, <30 pg/ml), IL-10 (<6 pg/ml), and interferon-γ (IFN-γ, <15 pg/ml). After propensity score analysis, children with interstitial pneumonia showed significantly higher CD19⁺, CD3⁺, and CD4⁺ T cell counts, and lower serum IL-6, IL-10, and IFN-γ levels. The final regression model showed that only CD4⁺ T cells (>1.5 × 10⁹/L, OR = 2.473), IFN-γ (<15 pg/ml, OR = 2.250), and hydrothorax free (OR = 14.454) were correlated with the development of interstitial pneumonia among children with MPP. Conclusions: The M. pneumoniae-induced interstitial pneumonia showed increased CD4⁺ T cells and lower serum IFN-γ level. Specific immunologic profiles could be involved in the development of pediatric interstitial pneumonia due to M. pneumoniae infections.

Lipid moieties of Mycoplasma pneumoniae lipoproteins are the causative factor of vaccine-enhanced disease

Vaccine-enhanced disease (VED) occurs as a result of vaccination followed by infection with virulent Mycoplasma pneumoniae. To date VED has prevented development of an efficacious vaccine against this significant human respiratory pathogen. Herein we report that vaccination of BALB/c mice with M. pneumoniae lipid-associated membrane proteins (LAMPs) induces lung lesions consistent with exacerbated disease following challenge, without reducing bacterial loads. Removal of lipid moieties from LAMPs prior to vaccination eliminates VED and reduces bacterial loads after infection. Collectively, these data indicate that lipid moieties of lipoproteins are the causative factors of M. pneumoniae VED.

Th17/IL-17 Axis Regulated by Airway Microbes Get Involved in the Development of Asthma

PURPOSE OF REVIEW

Bronchial asthma is a common respiratory disease induced by immune imbalance, characterized by chronic non-specific airway inflammation and airway hyperresponsiveness (AHR). Many factors induce asthma, among which respiratory infection is the important cause. In this review, we discuss how respiratory microbes participate in the occurrence and progression of asthma via Th17/IL-17 axis.

RECENT FINDINGS

Pathogenesis of asthma has been considered as closely related to the imbalance in number and function of Th1/Th2 in the CD4⁺ T lymphocyte subsets. Recent studies have shown that Th17 cell and its secretory IL-17 also play an important role in AHR. Respiratory virus, bacteria, fungi, and other respiratory microbial infections can directly or indirectly induce the differentiation of Th17 cell and the production of related cytokines to induce AHR. Respiratory microbial infection can affect the TH17/IL-17A axis through a variety of mechanisms, thereby promoting the occurrence and development of asthma, and these specific mechanisms may provide new effective therapeutic ideas for asthma.

Cytokine levels of peripheral blood mononuclear cells in the clinical cases of Holstein calves infected with Mycoplasma bovis

The immune related factors of peripheral blood mononuclear cells (PBMC) were analyzed in the clinical cases with Mycoplasma (M.) bovis infection. Seventy-eight Holstein calves in one farm were used. These calves were divided into three groups; the calves with M. bovis infection of poor outcome after treatment (Non-Recovery Group), the calves with M. bovis infection recovered (Recovery Group) and clinically healthy calves (Control Group). Blood samples were collected at days of the first medical treatment and the final treatment or euthanasia. IL-17A levels in the Non-Recovery Group were higher than those in the Recovery Group on both days. Our result suggested that the IL-17A of PBMC is an important factor to affect outcome of the calves with M. bovis infection.

Association of the infectious triggers with childhood Henoch-Schonlein purpura in Anhui province, China

BACKGROUND

Although the specific etiology of Henoch-Schonlein purpura (HSP) is still unknown, several kinds of infectious triggers have been proved to participate in its pathogenesis. The objectives of present study were to analyze the association of the infectious triggers with childhood HSP in Anhui province, China.

METHODS

1200 HSP children were recruited from January 2015 to December 2017. Serum antistreptolysin O titer, TORCH, Epstein-Barr virus, helicobacter pylori (HP), Mycoplasma antibodies (MP-Ab), tubercle bacillus antibody (TB-Ab), respiratory pathogens (legionella pneumophila, chlamydia pneumoniae, adenovirus, respiratory syncytial virus, influenza A virus, influenza B virus, rickettsia, parainfluenza virus) were determined. Patients' histories were obtained by interviews and questionnaires.

RESULTS

The annual incidence of HSP was 8.13-9.17 per 100,000. HSP occurred more commonly in spring and winter than in summer with an obvious west-to-east gradient. On admission, several potential infections were identified in 611 cases (50.92%). The infectious agents including streptococcus, HP, MP, parainfluenza, respiratory syncytial virus, TB and toxoplasma gondii were identified in 205 cases (17.08%), 71 cases (5.92%), 58 cases (4.83%), 6 cases (0.5%), 1 case (0.08%), 1 case (0.08%) and 1 case (0.08%) respectively. 123 cases (10.25%) relapsed or recurred more than one time; the mean number was 2.92, and the mean interval was 11.4 weeks. The infection was the most frequent trigger regardless of clinical phenotypes and relapse/recurrence. Symptomatic treatment plus adjunctive anti-infectious agents could significantly improve the remission rate of purpura in the infectious cases (x²=24.60, p<0.01).

CONCLUSIONS

Streptococcus is the most frequent infectious agent in HSP children regardless of clinical phenotype or relapse/recurrence. The complete elimination of infectious triggers may help relieve cutaneous purpura.

The role of miR-29c/B7-H3/Th17 axis in children with Mycoplasma pneumoniae pneumonia

Background

Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of community-acquired pneumonia in children. Recent studies demonstrated that the incidence of severe or fatal M. pneumoniae was gradually increasing, which may be related to the excessive inflammation. However, the exact pathogenesis of excessive inflammation in Mycoplasma pneumoniae pneumonia(MPP) is still unclear. This study aimed to reveal the role of miR-29c/B7-H3/Th17 axis in children with MPP.

Methods

Children hospitalized in Respiratory Department during Jan. 2014 to Dec. 2015 were enrolled. All children enrolled was confirmed with MP infection using real-time PCR and ELISA. Children were excluded if they were co-infected with other pathogens. A total of 52 children with MPP and 26 controls were enrolled. miR-29c expression in monocytes of children with MPP was determined by real-time PCR and soluble B7-H3 (sB7-H3) and IL-17 were determined by ELISA, and explore their clinical significance. miR-29c overexpression and silencing technology and luciferase reporter assay were performed to confirm whether B7-H3 is the direct target of miR-29c. The levels of transcription factor ROR-γt in CD4+ T cells and cytokine IL-17A in supernatant were detected after stimulated by different concentrations of B7-H3 fusion protein in vitro.

Results

Of all 52 children with MPP, the mean age of the children were 77 ± 33 months, and 23 cases were male accounting for 44.2%. Nineteen cases had pleural effusion accounting for 36.5%. Children with MPP had significantly lower level of miR-29c and higher level of sB7-H3 and IL-17 compared to controls (both P < 0.05). The level of miR-29c significantly increased during convalescent phase compared to that of acute phase while sB7-H3 and IL-17 significantly decreased during convalescent phase (both P < 0.05). There was a positive correlation between the level of sB7-H3 and IL-17 in children with MPP during acute-stage (r = 0.361,P = 0.009). Children with MPP combined with pleural effusion had significantly higher level of sB7-H3 compared to those without pleural effusion (9952.3 ± 3065.3 vs. 7449.7 ± 2231.5, pg/ml), and the levels of sB7-H3 was positively correlated with the number of days of fever. The level of miR-29c was negatively correlated with M. pneumoniae specific IgG, IgM level. High concentrations of B7-H3(15μg/ml) could enhance ROR-γt expression and increase IL-17A. Functional studies based on luciferase reporter assay and immunofluorescence staining suggested that B7-H3 is the direct target of miR-29c, and miR-29c silencing or overexpression could up- or down-regulate the expression of B7-H3 in THP-1 cells.

Conclusions

The axis of miR-29c/B7-H3/Th17 plays a vital role in children with MPP through excessive inflammation. miR-29c and B7-H3 may be the new target for the prevention and treatment of MPP, and may be the novel and potential biomarkers for the assessment of prognosis.

Systemic interleukins levels in community-acquired pneumonia and their association with adverse outcomes

Introduction: Community-acquired pneumonia (CAP) is still one of the major causes of morbidity and mortality worldwide. Pro-inflammatory and anti-inflammatory interleukins have been studied to elucidate the role that inflammation plays in its pathogenesis. The aim of this study is to investigate inflammation in CAP, by analyzing in dynamic, serum levels of six interleukins (IL) and their predictive value regarding adverse outcomes.

Materials and methods: Forty adult patients with CAP, admitted in the Teaching Hospital of Infectious Diseases, Cluj-Napoca, Romania from December 2015 to February 2017, were enrolled in this study. Serum levels of pro-inflammatory: IL1β, TNF-α, IL-6, anti-inflammatory: IL-10 and IL-4, along with IL-17A were analyzed in dynamic, on day 1 and day 4.The receiver – operator curves (ROC) were used to analyze the outcome prediction of IL.

Results: Serum levels of IL-1β, IL-6, TNF-α and IL-10 have decreased significantly in dynamic, while IL-4 increases. IL-17A has acted like a pro-inflammatory cytokine. We have found a correlation between IL-6 and IL-10 (r=0.429, p=0.000), IL-6 and IL-17A (r=0.295, p=0.008) and IL-10 and IL-17A (r=0.475, p=0.000). Out of 40 patients, 9 had adverse outcomes, consisting in 9 relapses from which 1 died. IL-6 discriminates alone between adverse and favorable outcomes. With multivariate analysis and multiple regression of all combined IL, we have found that there is a predictive model regarding adverse outcomes.

Conclusion: IL-10 and IL-17A behave like pro-inflammatory cytokines. IL-6 is a predictive marker for adverse outcomes alone. All IL studied together have an impact on adverse outcomes.

Impact of atopy on the severity and extrapulmonary manifestations of childhood Mycoplasma pneumoniae pneumonia

Objectives

The impact of atopy on disease severity and extrapulmonary manifestations in children with Mycoplasmapneumoniae (MP) pneumonia is unknown.

Methods

Patients diagnosed with MP pneumonia between January 2016, and December 2017, were enrolled in this study. A total of 150 MP pneumonia patients were enrolled at diagnosis and divided into the atopic group (n = 48) and the nonatopic group (n = 102). Furthermore, these patients were also assessed after being divided into the pulmonary group (n = 120) and the extrapulmonary group (n = 30). Clinical characteristics, respiratory disease severity, any allergy history, and specific allergen sensitizations were collected from all patients. The serum interleukin‐17 (IL‐17) and total immunoglobulin E (lgE) levels were also measured.

Results

More children in the atopic group than those in the nonatopic group presented with severe MP pneumonia, tachypnea, oxygen therapy, steroid treatment, atopic conditions including asthma attack, a previous history of asthma, decreased IL‐17 levels, and increased IgE levels (all P < 0.05). When compared with those in the pulmonary group, the patients in the extrapulmonary group showed higher percentages of atopy, higher total lgE levels, and lower IL‐17 levels (all P < 0.05).

Conclusions

Atopy may be a risk factor for disease severity and extrapulmonary manifestations in children with MP pneumonia.

Antibodies to Protein but Not Glycolipid Structures Are Important for Host Defense against Mycoplasma pneumoniae

Antibody responses to Mycoplasma pneumoniae correlate with pulmonary M. pneumoniae clearance. However, M. pneumoniae-specific IgG antibodies can cross-react with the myelin glycolipid galactocerebroside (GalC) and cause neurological disorders. We assessed whether antiglycolipid antibody formation is part of the physiological immune response to M. pneumoniae We show that antibodies against M. pneumoniae proteins and glycolipids arise in serum of M. pneumoniae-infected children and mice. Although antibodies to M. pneumoniae glycolipids were mainly IgG, anti-GalC antibodies were only IgM. B-1a cells, shown to aid in protection against pathogen-derived glycolipids, are lacking in Bruton tyrosine kinase (Btk)-deficient mice. M. pneumoniae-infected Btk-deficient mice developed M. pneumoniae-specific IgG responses to M. pneumoniae proteins but not to M. pneumoniae glycolipids, including GalC. The equal recovery from M. pneumoniae infection in Btk-deficient and wild-type mice suggests that pulmonary M. pneumoniae clearance is predominantly mediated by IgG reactive with M. pneumoniae proteins and that M. pneumoniae glycolipid-specific IgG or IgM is not essential. These data will guide the development of M. pneumoniae-targeting vaccines that avoid the induction of neurotoxic antibodies.

Ameliorative Effects of Infantile Feire Kechuan Oral Solution on Mycoplasma Pneumoniae Pneumonia in Infant Mouse and Rat Models

Mycoplasma pneumoniae (MP) infection is a major pathogen of community-acquired pneumonia (CAP) in children worldwide. Infantile Feire Kechuan Oral Solution (IFKOS) has been used for the treatment of MP pneumonia clinically in China for many years. The present study was designed to investigate the therapeutic effect of IFKOS on MP pneumonia and explore the potential mechanism of the actions. The infant BALB/c mouse and Wistar rat models of MP infection were successfully established to confirm the therapeutic effects of IFKOS, followed by assays for related cytokines and investigations of the IgM response involved. The results showed that IFKOS exhibited an inhibitory effect on pulmonary index (PI) and effectively reduced the degree of lesions in the lungs. The lethal rate of mice was significantly decreased while survival time of mice was dramatically increased by IFKOS treatment in comparison to infection control, respectively. IFKOS treatment (40, 20, and 10ml/kg) significantly decreased the level of MP-IgM in a dose-dependent manner, whereas IFKOS showed no obvious inhibitory effect on the increase of relative expression of MP-DNA. In addition, the elevated IL-2 and TNF-α levels were significantly reduced and the decreased IL-6 level was significantly enhanced by IFKOS treatment. Our study demonstrates that IFKOS has inhibitory effect on MP infection in infant mouse and rat models of MP pneumonia and protective effect from lethal MP challenge in infant murine model. These anti-MP effects might be related to suppression of the IgM response and a reversal the imbalance of Th1/Th2 cytokines induced by MP infection.

Time-series analysis: variation of anti-acetylcholine receptor antibody titer in myasthenia gravis is related to incidence of Mycoplasma pneumoniae and influenza virus infections

Objectives The exacerbating factors of myasthenia gravis (MG) are unknown. However, it has been speculated that infections may play a role in disease progression. Methods We calculated the adjusted anti-acetylcholine receptor antibody (Adj-AChR-Ab) titers (range, 0-1) in 58 MG patients between 2006 and 2012. We determined the relationship between Adj-AChR-Ab titer and infection incidence. Results A cross-correlation function (CCF) analysis of Adj-AChR-Ab titer and incidence of Mycoplasma pneumoniae (M. pneumoniae) (r = 0.449, P < 0.0001) and influenza virus (r = 0.411, P < 0.001) infections indicated significant correlations. MG with thymoma was highly correlated with M. pneumoniae infection (r = 0.798, P < 0.0001). The relative risk for Adj-AChR-Ab titer was 1.407 for M. pneumoniae (95% CI, 1.193-1.661 for an increase in one infected patient per monitoring point) and 1.158 for influenza (95% CI, 1.071-1.253 for 100 infected patients). Conclusion Variation of Adj-AChR-Ab titer is significantly influenced by the presence of M. pneumoniae and influenza virus infections.

ATF3 inhibits the inflammation induced by Mycoplasma pneumonia in vitro and in vivo

OBJECTIVES

Activating transcription factor-3 (ATF3) is a key regulator of inflammatory responses. We aimed to investigate the effects and mechanisms of ATF3 on the inflammatory cytokines are induced by Mycoplasma pneumonia (MP).

STUDY DESIGN

RAW264.7 and mouse peritoneal macrophages were exposed to various time with or without MP infection (3, 6, 12, 24, and 48 h), and detect the expression of ATF3. Adenovirus-expression of ATF3 (Ad/ATF3) or Ad/βgal was transfected into cells which were exposed to MP for 48 h, RT-PCR and ELISA was used to evaluate the expression and secretion of TNF-α, IL-1β, IL-6, and IL-18. In addition, intravenous administration Ad/ATF3 or Ad/βgal into the mice, the secretion of inflammatory cytokines were detected using ELISA. ChIP assay was used to determine whether ATF3 can bind to the promoter of Early growth response protein 1 (Egr-1). Western blot was used to detect the expression of Egr-1 and Fyn.

RESULTS

ATF3 was increased at 3, 6, 12, and 24 h and the highest expression levels occurs in 6 h, there is no significant differences at 24 and 48 h compared with 0 h or CON group in RAW 264.7. Similar results were seen in mouse peritoneal macrophages. Overexpression of ATF3 resulted in the reduction of inflammatory cytokines. ChIP assay revealed that ATF3 can bind to the promoter of Egr-1. Overexpression of ATF3 inhibited the protein expression of Egr-1 and Fyn; conversely, ATF3-deficiency promoted the expression of Egr-1 and Fyn. Overexpression of Egr-1 reduced the anti-inflammatory action of ATF3.

CONCLUSIONS

ATF3 inhibit the expression and release of TNF-α, IL-1β, IL-6, and IL-18 induced by MP in vitro and in vivo, which is associated with its negative regulation of Egr-1/Fyn signaling pathway.

Increased Serum Interleukin-10 but not Interleukin-4 Level in Children with Mycoplasma pneumoniae Pneumonia

BACKGROUND

Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia in children, and it has been associated with wheezing. The aim of this study was to examine the serum level of interleukin (IL)-4 and IL-10 in children with Mycoplasma pneumoniae pneumonia (MPP) and to analyse them in relation to the presence of wheezing.

METHODS

The study included 166 children with radiologically confirmed pneumonia. MP infection was confirmed by enzyme-linked immunosorbent assay (ELISA) serum MP-IgM and MP-IgG test and throat swab MP DNA with real-time polymerase chain reaction. Serum levels of IL-4 and IL-10 were measured using ELISA.

RESULTS

There was no significant difference in serum level of IL-4 between children with MPP and those with non-MPP. Among children with MPP, we found similar level of IL-4 regardless of the personal and family history of allergy and asthma or the presence of wheezing. A significantly higher level of IL-10 was found in children with MPP than in children with non-MPP (32.92±18.582 vs. 27.01±14.100 pg/ml, p =0.022). Furthermore, wheezing children with MPP had a significantly higher level of IL-10 than children with MPP without wheezing (43.75±26.644 vs. 27.50±10.211 pg/ml, p=0.027).

CONCLUSION

Our results show significantly increased serum level of IL-10 in children with MPP, which was significantly higher in children with wheezing. These findings may suggest a role of IL-10 in the pathogenesis of MPP and in the occurrence of wheezing during acute MP infection.

Insights into the pathogenesis of Mycoplasma pneumoniae (Review)

Mycoplasma are the smallest prokaryotic microbes present in nature. These wall-less, malleable organisms can pass through cell filters, and grow and propagate under cell-free conditions in vitro. Of the pathogenic Mycoplasma Mycoplasma pneumoniae has been examined the most. In addition to primary atypical pneumonia and community-acquired pneumonia with predominantly respiratory symptoms, M. pneumoniae can also induce autoimmune hemolytic anemia and other diseases in the blood, cardiovascular system, gastrointestinal tract and skin, and can induce pericarditis, myocarditis, nephritis and meningitis. The pathogenesis of M. pneumoniae infection is complex and remains to be fully elucidated. The present review aimed to summarize several direct damage mechanisms, including adhesion damage, destruction of membrane fusion, nutrition depletion, invasive damage, toxic damage, inflammatory damage and immune damage. Further investigations are required for determining the detailed pathogenesis of M. pneumoniae.

Increased Frequency of Th17 Cells in Children With Mycoplasma pneumoniae Pneumonia

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae, MP) is recognized globally as a significant cause of primary atypical pneumonia in humans, particularly in children. Overzealous host immune responses are viewed as key mediators of the pathogenesis of M. pneumoniae infection. Although Th17 cells have been identified as key modulators in the clearance of pathogens and induction of autoimmunity caused by excessive immune responses, little is known about the role of Th17 cells in patients with M. pneumoniae infection.

METHODS

The percentages of T cells, CD4⁺ T cells and Th17 cells in children with M. pneumoniae infection were measured by flow cytometry.

RESULTS

We documented an increased frequency of Th17 cells in children with M. pneumoniae infection. Furthermore, we found a significantly higher percentage of Th17 cells in M. pneumoniae-infected children with extrapulmonary manifestations, compared with children without extrapulmonary manifestations. In addition, patients who experienced a short course of Mycoplasma pneumoniae pneumonia (MPP) showed an increase in the percentage of Th17 cells.

CONCLUSION

Our findings suggest that Th17 cells may be involved in the clearance of M. pneumoniae during an acute infection. Excessive Th17 cell responses may also contribute to the immuno-pathological damage observed during persistent infection.

Systems Vaccinology: Applications, Trends, and Perspectives

The strategies employed in vaccinology have improved since the seminal work of Edward Jenner in the eighteenth century. Stimulated by failure to develop vaccines for cancers and chronic infectious diseases as well as an emergence of a multitude of new technologies not available earlier, vaccinology has moved from a largely experimental art to a new phase of innovation. Currently, immune reactions can be predicted and modeled before they occur and formulations can be optimized in advance for genetic background, age, sex, lifestyle, environmental factors, and microbiome. A multitude of scientific insights and technological advancements have led us to this current status, yet possibly none of the recent developments is individually more promising to achieve these goals than the interdisciplinary science of systems vaccinology. This review summarizes current trends and applications of systems vaccinology, including technically tangible areas of vaccine and immunology research which allow the transformative process into a truly broad understanding of vaccines, thereby effectively modeling interaction of vaccines with health and disease. It is becoming clear that a multitude of factors have to be considered to understand inter-patient variability of vaccine responses including those characterized from the interfaces between the immune system, microbiome, metabolome, and the nervous system.

Preclinical safety and efficacy models for pulmonary drug delivery of antimicrobials with focus on in vitro models

New pharmaceutical formulations must be proven as safe and effective before entering clinical trials. Also in the context of pulmonary drug delivery, preclinical models allow testing of novel antimicrobials, reducing risks and costs during their development. Such models allow reducing the complexity of the human lung, but still need to reflect relevant (patho-) physiological features. This review focuses on preclinical pulmonary models, mainly in vitro models, to assess drug safety and efficacy of antimicrobials. Furthermore, approaches to investigate common infectious diseases of the respiratory tract, are emphasized. Pneumonia, tuberculosis and infections occurring due to cystic fibrosis are in focus of this review. We conclude that especially in vitro models offer the chance of an efficient and detailed analysis of new antimicrobials, but also draw attention to the advantages and limitations of such currently available models and critically discuss the necessary steps for their future development.