Could the airway epithelium play an important role in mucosal immunoglobulin A production?

Persistent microbial infections and idiopathic pulmonary fibrosis - an insight into non-typeable Haemophilus influenza pathogenesis

Interstitial lung disease (ILD) is characterized by chronic inflammation and scarring of the lungs, of which idiopathic pulmonary fibrosis (IPF) is the most devastating pathologic form. Idiopathic pulmonary fibrosis pathogenesis leads to loss of lung function and eventual death in 50% of patients, making it the leading cause of ILD-associated mortality worldwide. Persistent and subclinical microbial infections are implicated in the acute exacerbation of chronic lung diseases. However, while epidemiological studies have highlighted pollutants, gastric aspirate, and microbial infections as major causes for the progression and exacerbation of IPF, the role of persistent microbial infections in the pathogenesis of IPF remains unclear. In this review, we have focused on the role of persistent microbial infections, including viral, bacterial, and fungal infections, and their mechanisms of action in the pathogenesis of IPF. In particular, the mechanisms and pathogenesis of the Gram-negative bacteria Non-typeable Haemophilus influenzae (NTHi) in ILDs are discussed, along with growing evidence of its role in IPF, given its unique ability to establish persistent intracellular infections by leveraging its non-capsulated nature to evade host defenses. While antibiotic treatments are presumably beneficial to target the extracellular, interstitial, and systemic burden of pathogens, their effects are significantly reduced in combating pathogens that reside in the intracellular compartments. The review also includes recent clinical trials, which center on combinatorial treatments involving antimicrobials and immunosuppressants, along with antifibrotic drugs that help mitigate disease progression in IPF patients. Finally, future directions focus on mRNA-based therapeutics, given their demonstrated effectiveness across a wide range of clinical applications and feasibility in targeting intracellular pathogens.

Respiratory mucosal vaccination of peptide-poloxamine-DNA nanoparticles provides complete protection against lethal SARS-CoV-2 challenge

The ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). The pSpike/PP-sNp not only displays superior gene transfection and favorable biocompatibility in the mouse airway, but also promotes a tripartite immunity consisting of systemic, cellular, and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, immunization with pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp is a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2.

Disease-related disgust promotes antibody release in human saliva

The behavioral immune system (BIS) comprises manifold mechanisms, that may assist the physiological immune system (PIS) in counteracting infection and can even reduce the risk of contagion. Previous studies have found initial evidence for possible interactions between the two systems. However, most of these findings were correlative and have not been replicated. Further, none of these studies examined whether disease stimuli that indicate an enhanced airborne transmission risk may trigger a different immune response in comparison to stimuli that predominantly evoke core disgust. In the present study, we employed a video-priming approach to get further insight in the influence of the perception of disgust- and disease-related stimuli on the rapid physiological immune response, as indicated by changes of secretory immunoglobulin A (S-IgA) in saliva. We created three video primers that represented different categories of disgust- and/or disease-associated content. Two of the videos showed disease-related situations that were associated with contagious respiratory virus infections, varying in concealment of aerosols. The third video incurred no heightened airborne contagion risk, but comprised situations that are known to elicit core disgust, such as rotten foods, decaying animal carcasses, or cockroaches. A fourth video acted as control showing landscape impressions. The different video primers varied in their contagion risk and disgust-evoking potential. Given the role of S-IgA in the mucosal immune defense, we expected differences in the S-IgA response between the two videos indicating a heightened airborne contagion risk and the core disgust video, with the highest S-IgA to occur after the aerosol video. For this, we used the data of 107 healthy participants in a between-subjects design with the four video primers. We found a significant increase of S-IgA in response to both the disease- and the disgust-related videos, which correlated positively with the perceived contagion risk of the displayed situations. Nevertheless, there was no significant difference in the increase between the three disease- and disgust-related videos. We also found that people with a high contamination disgust produced less S-IgA in such situations, which is a hint for a compensating relationship between the BIS and PIS. Our observations suggest that the mere visual perception of videos showing realistic situations of an increased contagion risk can elicit a heightened release of salivary antibodies.

•

Realistic videos of respiratory diseases are efficient to trigger immune responses.

•

Secretory Immunoglobulin A (S-IgA) in saliva increases after video-priming.

•

S-IgA increase is positively correlated with perceived contagion risk.

•

S-IgA increase is inversely correlated with the trait contamination disgust.

Deficiency of leukocyte-specific protein 1 (LSP1) alleviates asthmatic inflammation in a mouse model

Background

Asthma is a major cause of morbidity and mortality in humans. The mechanisms of asthma are still not fully understood. Leukocyte-specific protein-1 (LSP-1) regulates neutrophil migration during acute lung inflammation. However, its role in asthma remains unknown.

Methods

An OVA-induced mouse asthma model in LSP1-deficient (Lsp1^−/−) and wild-type (WT) 129/SvJ mice were used to test the hypothesis that the absence of LSP1 would inhibit airway hyperresponsiveness and lung inflammation.

Results

Light and electron microscopic immunocytochemistry and Western blotting showed that, compared with normal healthy lungs, the levels of LSP1 were increased in lungs of OVA-asthmatic mice. Compared to Lsp1^−/− OVA mice, WT OVA mice had higher levels of leukocytes in broncho-alveolar lavage fluid and in the lung tissues (P < 0.05). The levels of OVA-specific IgE but not IgA and IgG1 in the serum of WT OVA mice was higher than that of Lsp1^−/− OVA mice (P < 0.05). Deficiency of LSP1 significantly reduced the levels of IL-4, IL-5, IL-6, IL-13, and CXCL1 (P < 0.05) but not total proteins in broncho-alveolar lavage fluid in asthmatic mice. The airway hyper-responsiveness to methacholine in Lsp1^−/− OVA mice was improved compared to WT OVA mice (P < 0.05). Histology revealed more inflammation (inflammatory cells, and airway and blood vessel wall thickening) in the lungs of WT OVA mice than in those of Lsp1^−/− OVA mice. Finally, immunohistology showed localization of LSP1 protein in normal and asthmatic human lungs especially associated with the vascular endothelium and neutrophils.

Conclusion

These data show that LSP1 deficiency reduces airway hyper-responsiveness and lung inflammation, including leukocyte recruitment and cytokine expression, in a mouse model of asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02078-7.

Teleost swim bladder, an ancient air-filled organ that elicits mucosal immune responses

The air-filled organs (AOs) of vertebrates (lungs and swim bladders) have evolved unique functions (air-breathing or buoyancy control in water) to adapt to different environments. Thus far, immune responses to microbes in AOs have been described exclusively in the lungs of tetrapods. Similar to lungs, swim bladders (SBs) represent a mucosal surface, a feature that leads us to hypothesize a role for SB in immunity. In this study, we demonstrate that secretory IgT (sIgT) is the key SB immunoglobulin (Ig) responding to the viral challenge, and the only Ig involved in viral neutralization in that organ. In support of these findings, we found that the viral load of the SB from fish devoid of sIgT was much higher than that of control fish. Interestingly, similar to the lungs in mammals, the SB represents the mucosal surface in fish with the lowest content of microbiota. Moreover, sIgT is the main Ig class found coating their surface, suggesting a key role of this Ig in the homeostasis of the SB microbiota. In addition to the well-established role of SB in buoyancy control, our findings reveal a previously unrecognized function of teleost SB in adaptive mucosal immune responses upon pathogenic challenge, as well as a previously unidentified role of sIgT in antiviral defense. Overall, our findings indicate that despite the phylogenetic distance and physiological roles of teleost SB and mammalian lungs, they both have evolved analogous mucosal immune responses against microbes which likely originated independently through a process of convergent evolution.

The Effects of Physical Exercise on Saliva Composition: A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

Current advances and future challenges of AIoT applications in particulate matters (PM) monitoring and control

Air pollution is at the center of pollution-control discussion due to the significant adverse health effects on individuals and the environment. Research has shown the association between unsafe environments and different sizes of particulate matter (PM), highlighting the importance of pollutant monitoring to mitigate its detrimental effect. By monitoring air quality with low-cost monitoring devices that collect massive observations, such as Air Box, a comprehensive collection of ground-level PM concentration is plausible due to the simplicity and low-cost, propelling applications in agriculture, aquaculture, and air quality, water resources, and disaster prevention. This paper aims to view IoT-based systems with low-cost microsensors at the sensor, network, and application levels, along with machine learning algorithms that improve sensor networks' precision, providing better resolution. From the analysis at the three levels, we analyze current PM monitoring methods, including the use of sensors when collecting PM concentrations, demonstrate the use of IoT-based systems in PM monitoring and its challenges, and finally present the integration of AI and IoT (AIoT) in PM monitoring, indoor air quality control, and future directions. In addition, the inclusion of Taiwan as a site analysis was illustrated to show an example of AIoT in PM-control policy-making potential directions.

Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19

INTRODUCTION

As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses.

AREAS COVERED

Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar.

EXPERT OPINION

We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

A Live-Attenuated Equine Influenza Vaccine Stimulates Innate Immunity in Equine Respiratory Epithelial Cell Cultures That Could Provide Protection From Equine Herpesvirus 1

Equine herpesvirus 1 (EHV-1) ubiquitously infects horses worldwide and causes respiratory disease, abortion, and equine herpesvirus myeloencephalopathy. Protection against EHV-1 disease is elusive due to establishment of latency and immune-modulatory features of the virus. These include the modulation of interferons, cytokines, chemokines, antigen presentation, and cellular immunity. Because the modulation of immunity likely occurs at the site of first infection—the respiratory epithelium, we hypothesized that the mucosal influenza vaccine Flu Avert^® I.N. (Flu Avert), which is known to stimulate strong antiviral responses, will enhance antiviral innate immunity, and that these responses would also provide protection from EHV-1 infection. To test our hypothesis, primary equine respiratory epithelial cells (ERECs) were treated with Flu Avert, and innate immunity was evaluated for 10 days following treatment. The timing of Flu Avert treatment was also evaluated for optimal effectiveness to reduce EHV-1 replication by modulating early immune responses to EHV-1. The induction of interferons, cytokine and chemokine mRNA expression, and protein secretion was evaluated by high-throughput qPCR and multiplex protein analysis. Intracellular and extracellular EHV-1 titers were determined by qPCR. Flu Avert treatment resulted in the modulation of IL-8, CCL2, and CXCL9 starting at days 5 and 6 post-treatment. Coinciding with the timing of optimal chemokine induction, our data also suggested the same timing for reduction of EHV-1 replication. In combination, our results suggest that Flu Avert may be effective at counteracting some of the immune-modulatory properties of EHV-1 at the airway epithelium and the peak for this response occurs 5–8 days post-Flu Avert treatment. Future in vivo studies are needed to investigate Flu Avert as a prophylactic in situations where EHV-1 exposure may occur.

The phenotypic and functional study of tissue B cells in respiratory system provided important information for diseases and development of vaccines

The field of tissue-resident B cells has received increasing attention, yet the feature of tissue B cells in respiratory system is unclear. Here, we first show that non-circulating B cells obtained from nasal, trachea and lung tissues are numerically and phenotypically distinct from their circulating counterparts. Analysis of single cell transcriptome sequence identified multiple differentially expressed genes between non-circulating B cells and circulating B cells, which illustrated their heterogeneity. Furthermore, we found high expression of CXCR3 on non-circulating B cells, and the chemokine CXCL11 was also up-regulated in the respiratory tissues, suggesting that CXCR3-CXCL11 axis might accelerate the local resident of non-circulating B cells in respiratory tract. Interestingly, intranasal immunization with BCG in mice elicited a sustained humoral immune response via induction of IgA and IgG Abs, which revealed the role of B cells. Meanwhile, tissue-resident B cells, IgA⁺ and IgG⁺ memory B cells (MBCs) in respiratory tissues, as well as plasma cells in bone marrow, were expanded and maintained, and these subsets probably developed into antibody-producing cells to participate in the local humoral immunity. Our data illustrate the phenotype and function of tissue B cells in the upper and lower airways, provide references for the prospective development of vaccines.

Regulatory B cells in respiratory health and diseases

B cells are critical mediators of humoral immune responses in the airways through antibody production, antigen presentation, and cytokine secretion. In addition, a subset of B cells, known as regulatory B cells (Bregs), exhibit immunosuppressive functions via diverse regulatory mechanisms. Bregs modulate immune responses via the secretion of IL‐10, IL‐35, and tumor growth factor‐β (TGF‐β), and by direct cell contact. The balance between effector and regulatory B cell functions is critical in the maintenance of immune homeostasis. The importance of Bregs in airway immune responses is emphasized by the different respiratory disorders associated with abnormalities in Breg numbers and function. In this review, we summarize the role of immunosuppressive Bregs in airway inflammatory diseases and highlight the importance of this subset in the maintenance of respiratory health. We propose that improved understanding of signals in the lung microenvironment that drive Breg differentiation can provide novel therapeutic avenues for improved management of respiratory diseases.

Multiple inducers and novel roles of autoantibodies against the obligatory NMDAR subunit NR1: a translational study from chronic life stress to brain injury

Circulating autoantibodies (AB) of different immunoglobulin classes (IgM, IgA, and IgG), directed against the obligatory N-methyl-D-aspartate-receptor subunit NR1 (NMDAR1-AB), belong to the mammalian autoimmune repertoire, and appear with age-dependently high seroprevalence across health and disease. Upon access to the brain, they can exert NMDAR-antagonistic/ketamine-like actions. Still unanswered key questions, addressed here, are conditions of NMDAR1-AB formation/boosting, intraindividual persistence/course in serum over time, and (patho)physiological significance of NMDAR1-AB in modulating neuropsychiatric phenotypes. We demonstrate in a translational fashion from mouse to human that (1) serum NMDAR1-AB fluctuate upon long-term observation, independent of blood-brain barrier (BBB) perturbation; (2) a standardized small brain lesion in juvenile mice leads to increased NMDAR1-AB seroprevalence (IgM + IgG), together with enhanced Ig-class diversity; (3) CTLA4 (immune-checkpoint) genotypes, previously found associated with autoimmune disease, predispose to serum NMDAR1-AB in humans; (4) finally, pursuing our prior findings of an early increase in NMDAR1-AB seroprevalence in human migrants, which implicated chronic life stress as inducer, we independently replicate these results with prospectively recruited refugee minors. Most importantly, we here provide the first experimental evidence in mice of chronic life stress promoting serum NMDAR1-AB (IgA). Strikingly, stress-induced depressive-like behavior in mice and depression/anxiety in humans are reduced in NMDAR1-AB carriers with compromised BBB where NMDAR1-AB can readily reach the brain. To conclude, NMDAR1-AB may have a role as endogenous NMDAR antagonists, formed or boosted under various circumstances, ranging from genetic predisposition to, e.g., tumors, infection, brain injury, and stress, altogether increasing over lifetime, and exerting a spectrum of possible effects, also including beneficial functions.

ACKR2 contributes to pulmonary dysfunction by shaping CCL5:CCR5-dependent recruitment of lymphocytes during influenza A infection in mice

Inflammation triggered by influenza A virus (IAV) infection is important for viral clearance, induction of adaptive responses, and return to lung homeostasis. However, an exaggerated immune response, characterized by the overproduction of chemokines, can lead to intense lung injury, contributing to mortality. Chemokine scavenger receptors, such as ACKR2, control the levels of CC chemokines influencing the immune responses. Among the chemokine targets of ACKR2, CCL5 is important to recruit and activate lymphocytes. We investigated the role of ACKR2 during IAV infection in mice. Pulmonary ACKR2 expression was increased acutely after IAV infection preceding the virus-induced lung dysfunction. ACKR2-knockout (ACKR2−/−) mice were protected from IAV, presenting decreased viral burden and lung dysfunction. Mechanistically, the absence of ACKR2 resulted in augmented airway CCL5 levels, secreted by mononuclear and plasma cells in the lung parenchyma. The higher chemokine gradient led to an augmented recruitment of T and B lymphocytes, formation of inducible bronchus-associated lymphoid tissue and production of IgA in the airways of ACKR2−/− mice post-IAV. CCL5 neutralization in ACKR2−/− mice prevented lymphocyte recruitment and increased bronchoalveolar lavage fluid protein levels and pulmonary dysfunction. Finally, CCR5−/− mice presented increased disease severity during IAV infection, displaying increased neutrophils, pulmonary injury and dysfunction, and accentuated lethality. Collectively, our data showed that ACKR2 dampens CCL5 levels and the consequent recruitment of CCR5+ T helper 1 (Th1), T regulatory cells (Tregs), and B lymphocytes during IAV infection, decreasing pathogen control and promoting lung dysfunction in wild type mice. Therefore, ACKR2 is detrimental and CCR5 is protective during IAV infection coordinating innate and adaptive immune responses in mice.

Indoor exposure to Streptomyces albus and Aspergillus versicolor elevates the levels of spore-specific IgG, IgG1 and IgG3 serum antibodies in building users - A new ELISA-based assay for exposure assessment

Moisture-indicative microbes in buildings are associated with a variety of symptoms, ranging from mild irritation to severe clinical illnesses. These symptoms are caused principally by dried, dormant and dead microbe material like spores, mycelium and microbe metabolites, leading to the activation of the immune system and formation of the antigen-specific immunoglobulins. This activation presumably takes place through the respiratory track and is a normal immune reaction against pathogenic invaders. During continuous exposure, a prolonged state of inflammation will follow, and this forms a considerable health risk for a building's occupant. A new ELISA system utilizing spores from two species Streptomyces albus and Aspergillus versicolor as an antigen was developed to reveal the related immunological processes. In 159 persons, microbial exposure was observed to increase the levels of spore-specific IgG, IgG1 and IgG3 serum antibody levels of individuals residing in microbe-dense buildings compared with the control reference buildings. No differences were detected in the levels of S. albus- and A. versicolor-specific serum IgA or IgM levels.

The role of noncoding RNAs in regulating epithelial responses in COPD

Chronic obstructive pulmonary disease (COPD), one of the leading causes of death in the world, is a chronic inflammatory disease of the airways usually caused by long-term exposure to inhaled irritants. Airway epithelial cells (AECs) play a key role in initializing COPD and driving the exacerbation of this disease through the release of various cytokines. This AEC-derived cytokine response is tightly regulated possibly through the regulatory effects of noncoding RNAs (ncRNAs). Although the importance of ncRNAs in pulmonary diseases has been increasingly realized, little is known about the role of ncRNA in the regulation of inflammatory responses in COPD. This review outlines the features of AEC-derived cytokine responses in COPD and how ncRNAs regulate these inflammatory responses.

Exhaled nitric oxide and vascular endothelial growth factor as predictors of cold symptoms after stress

OBJECTIVE

Prior research has demonstrated that psychosocial stress is associated with respiratory infections. Immunologic, endocrine, and cardiovascular predictors of such infections have been explored with varying success. We therefore sought to study the unexplored role of airway mucosal immunity factors, nitric oxide (NO) and vascular endothelial growth factor (VEGF). NO is secreted by airway epithelial cells as part of the first line of defense against bacteria, viruses, and fungi. VEGF is expressed by mast cells in respiratory infections and recruits immune cells to infected sites, but in excess lead to vulnerability of the airway epithelium.

METHODS

In this proof-of-concept study we measured exhaled NO, exhaled breath condensate (EBC) VEGF, salivary VEGF, and salivary cortisol in 36 students undergoing final academic examinations at three occasions: a low-stress baseline during the term, an early phase of finals, and a late phase of finals. Participants also reported on cold symptoms at these time points and approximately 5 and 10days after their last academic examination.

RESULTS

Higher baseline NO was associated with fewer cold symptoms after stress, whereas higher baseline VEGF in EBC and saliva were associated with more cold symptoms after stress. Perceived stress at baseline as well as salivary VEGF and cortisol late in the finals also contributed to the prediction of later cold symptoms.

CONCLUSION

Basal levels of NO and VEGF may inform about mucosal immunocompetence and add to preventative treatments against airway infections from periods of stress in daily life.

Irgm1 coordinately regulates autoimmunity and host defense at select mucosal surfaces

The pathogenesis of primary Sjogren's syndrome (SS), an autoimmune disease that targets the mucosa of exocrine tissues, is poorly understood. Although several mouse models have been developed that display features of SS, most of these are within the larger context of a lupus-like presentation. Immunity-related GTPase family M protein 1 (Irgm1) is an interferon-inducible cytoplasmic GTPase that is reported to regulate autophagy and mitochondrial homeostasis. Here, we report that naive Irgm1-/- mice display lymphocytic infiltration of multiple mucosal tissues including the lung in a manner reminiscent of SS, together with IgA class-predominant autoantibodies including anti-Ro and anti-La. This phenotype persists in the germ-free state, but is abolished by deletion of Irgm3. Irgm1-/- mice have increased local production in the lung of TECP15-idiotype IgA, a natural antibody with dual reactivity against host and pneumococcal phosphorylcholine. Associated with this, Irgm1-/- mice display enhanced opsonization and clearance of Streptococcus pneumoniae from the lung and increased survival from pneumococcal pneumonia. Taken together, our results identify Irgm1 as a master regulator of mucosal immunity that dually modulates evolutionarily conserved self- and other-directed immune responses at the interface of host with environment.

Expression of CysLTR1 and 2 in Maturating Lymphocytes of Hyperplasic Tonsils Compared to Peripheral Cells in Children

Cysteinyl-leukotriene receptors 1 and 2 (CysLTR1 and 2) are related to allergic inflammatory responses. Recent studies demonstrated their role in lymphocyte division and maturation in the bone marrow. Few data are available about CysLTRs function in lymphocyte maturation in tonsils. The objectives of this study are to compare CysLTRs expression in peripheral blood lymphocytes with expression in maturating lymphocytes of hyperplasic tonsil and to check the influence of respiratory allergies in this process. Leukocytes of peripheral blood (PL) and hyperplasic tonsils of children were immunostained for CysLTR1, CysLTR2, CD3 (T cells), and CD19 (B cells) and read in flow cytometer. Lymphocyte of tonsils were divided in differentiating small cells (SC) and mitotic large cells (LC); percentage of B and T cells expressing CysLTRs was determined, and comparison was done using ANOVA and Tukey's tests. Data were analyzed as a whole and categorizing patients according the presence of allergies. Sixty children were enrolled in this study. There was a large expression of CysLTR1 and 2 in CD3+ LC, and such expression decreased progressively in SC and PL. In B cells, the highest expression of CysLTR1 and 2 was found in PL while SC showed the lowest and LC showed the intermediate expression. This pattern kept unchanged in groups of allergic and non-allergic individuals. CysLTRs seem to be involved in lymphocyte maturation that occurs in tonsils, without influence of allergies. New studies aiming the clinic treatment of tonsil hyperplasia must be targeted to the development of drugs capable of blocking both CysLTR1 and 2.

Expression of SCGB1C1 gene as a potential marker of susceptibility to upper respiratory tract infections in elite athletes - a pilot study

High levels of exercise in athletes result in temporary immunosuppression, which could increase the susceptibility to upper respiratory tract infections. Understanding of immunological mechanisms responsible for this phenomenon could enable optimization of training schemes for elite athletes and avoidance of infection-related episodes of absence during sports championships. The aim of this study was to detect genes that may be responsible for modulation of individual susceptibility to infections. The blood and saliva samples were collected from 10 healthy, medically examined kayakers (4 females and 6 males) aged 24.7 ± 2.3 years. All samples were taken in the morning, after overnight fasting, in a seated position. The ELISA method was used to determine the levels of secretory immunoglobulin A (sIgA) and interleukin 5 (IL-5). Whole genome expression in blood was assessed using microarrays. The study did not reveal any significant correlation between genome expression and sIgA concentration. However, low expression of a gene involved in protection against the common cold – secretoglobin 1C1 (SCGB1C1) – was detected in athletes with high IL-5 concentrations (corrected p = 0.00065; fold change = 3.17). Our results suggest that blood expression of the SCGB1C1 gene might be a marker of susceptibility to upper respiratory tract infections in athletes.

Mucosal immunoglobulins at respiratory surfaces mark an ancient association that predates the emergence of tetrapods

Gas-exchange structures are critical for acquiring oxygen, but they also represent portals for pathogen entry. Local mucosal immunoglobulin responses against pathogens in specialized respiratory organs have only been described in tetrapods. Since fish gills are considered a mucosal surface, we hypothesized that a dedicated mucosal immunoglobulin response would be generated within its mucosa on microbial exposure. Supporting this hypothesis, here we demonstrate that following pathogen exposure, IgT⁺ B cells proliferate and generate pathogen-specific IgT within the gills of fish, thus providing the first example of locally induced immunoglobulin in the mucosa of a cold-blooded species. Moreover, we demonstrate that gill microbiota is predominantly coated with IgT, thus providing previously unappreciated evidence that the microbiota present at a respiratory surface of a vertebrate is recognized by a mucosal immunoglobulin. Our findings indicate that respiratory surfaces and mucosal immunoglobulins are part of an ancient association that predates the emergence of tetrapods.

In teleost fish the gills perform—in addition to respiration—functions such as immune defence. Here the authors show that IgT, a teleost specific Ig previously shown to be involved in gut and skin mucosal immunity, is locally induced in the gill, where it plays a key role in immunity in rainbow trout.

Airway Gland Structure and Function

Submucosal glands contribute to airway surface liquid (ASL), a film that protects all airway surfaces. Glandular mucus comprises electrolytes, water, the gel-forming mucin MUC5B, and hundreds of different proteins with diverse protective functions. Gland volume per unit area of mucosal surface correlates positively with impaction rate of inhaled particles. In human main bronchi, the volume of the glands is ∼ 50 times that of surface goblet cells, but the glands diminish in size and frequency distally. ASL and its trapped particles are removed from the airways by mucociliary transport. Airway glands have a tubuloacinar structure, with a single terminal duct, a nonciliated collecting duct, then branching secretory tubules lined with mucous cells and ending in serous acini. They allow for a massive increase in numbers of mucus-producing cells without replacing surface ciliated cells. Active secretion of Cl(-) and HCO3 (-) by serous cells produces most of the fluid of gland secretions. Glands are densely innervated by tonically active, mutually excitatory airway intrinsic neurons. Most gland mucus is secreted constitutively in vivo, with large, transient increases produced by emergency reflex drive from the vagus. Elevations of [cAMP]i and [Ca(2+)]i coordinate electrolyte and macromolecular secretion and probably occur together for baseline activity in vivo, with cholinergic elevation of [Ca(2+)]i being mainly responsive for transient increases in secretion. Altered submucosal gland function contributes to the pathology of all obstructive diseases, but is an early stage of pathogenesis only in cystic fibrosis.

Effect of Nasal Corticosteroid on Secretory Immunoglobulin A Measured in Rat Nasal Lavage: Experimental Study

OBJECTIVE

In this study, we aimed to experimentally investigate the effects of nasal corticosteroids on the levels of secretory immunoglobulin A (sIgA) in nasal mucosa in rats.

STUDY DESIGN

Prospective, randomized control trial.

SETTING

Research laboratory.

SUBJECT AND METHODS

Twenty-four male Sprague Dawley rats were included in our study. The rats were randomized into 3 groups. In group 1, nasal mometasone furoate was applied to the rats for 30 days. Saline was applied to group 2 for 30 days. Group 3 was the control group and received no treatment throughout the study period. Nasal lavage was conducted on both nasal openings of all rats in the 3 groups at the beginning of the study and on days 15 and 30, and the lavage solution (distilled water) was collected by aspiration.

RESULTS

In group 1, the sIgA value was significantly higher at day 15 than at baseline. No significant difference was found between the sIgA values on day 15 and day 30. In groups 2 and 3, there were no significant differences in sIgA values at baseline, day 15, and day 30. The sIgA value of group 1 on day 15 was significantly higher than the values of groups 2 and 3. The sIgA value of group 1 on day 30 was significantly higher than the values of groups 2 and 3.

CONCLUSION

Topical corticosteroids (mometasone furoate) applied to the nasal mucosa significantly increase nasal sIgA levels.

Bronchial epithelial cells: The key effector cells in the pathogenesis of chronic obstructive pulmonary disease?

The primary function of the bronchial epithelium is to act as a defensive barrier aiding the maintenance of normal airway function. Bronchial epithelial cells (BEC) form the interface between the external environment and the internal milieu, making it a major target of inhaled insults. However, BEC can also serve as effectors to initiate and orchestrate immune and inflammatory responses by releasing chemokines and cytokines, which recruit and activate inflammatory cells. They also produce excess reactive oxygen species as a result of an oxidant/antioxidant imbalance that contributes to chronic pulmonary inflammation and lung tissue damage. Accumulated mucus from hyperplastic BEC obstructs the lumen of small airways, whereas impaired cell repair, squamous metaplasia and increased extracellular matrix deposition underlying the epithelium is associated with airway remodelling particularly fibrosis and thickening of the airway wall. These alterations in small airway structure lead to airflow limitation, which is critical in the clinical diagnosis of chronic obstructive pulmonary disease (COPD). In this review, we discuss the abnormal function of BEC within a disturbed immune homeostatic environment consisting of ongoing inflammation, oxidative stress and small airway obstruction. We provide an overview of recent insights into the function of the bronchial epithelium in the pathogenesis of COPD and how this may provide novel therapeutic approaches for a number of chronic lung diseases.

Repeated bouts of eccentrically biased endurance exercise stimulate salivary IgA secretion rate

To determine the salivary secretory immunoglobulin A (sIgA) response to repeated bouts of unaccustomed, downhill running (eccentrically biased) and examine potential protective immunological adaption from a repeated bout effect. Eleven active but untrained males (age: 19.7±0.4 years; VO_2peak: 47.8± 3.6 ml · kg⁻¹ · min ⁻¹) performed two 60 min bouts (Run 1 and Run 2) of downhill running (−13.5% gradient), separated by 14 days, at a speed eliciting 75% of their VO_2peak on a level grade. Saliva samples were collected before (baseline), immediately post exercise (IPE), and every hour for 12 h and every 24 h for 6 days after each run. Salivary sIgA concentration was measured and sIgA secretion rate was calculated. Results were analysed using repeated measures ANOVA (12 h period: 2x14; 24 h intervals: 2x7; p ≤ 0.05) with Tukey post-hoc tests where appropriate. Results are reported as means ± SE. There was a significant (p < 0.0001) interaction effect for sIgA secretion rate, IPE, with higher values after Run 2, as well as a significant (p < 0.01) time effect with elevated levels IPE and between 24 h and 144 h. There was a run effect (p < 0.0001), with the sIgA secretion rate significantly higher after Run 2. Repeated bouts of unaccustomed, eccentrically biased exercise induced alterations in the salivary sIgA secretion rate. This may serve as a protective mucosal adaptation to exercise-induced tissue damage.

B-lymphocyte lineage cells and the respiratory system

Adaptive humoral immune responses in the airways are mediated by B cells and plasma cells that express highly evolved and specific receptors and produce immunoglobulins of most isotypes. In some cases, such as autoimmune diseases or inflammatory diseases caused by excessive exposure to foreign antigens, these same immune cells can cause disease by virtue of overly vigorous responses. This review discusses the generation, differentiation, signaling, activation, and recruitment pathways of B cells and plasma cells, with special emphasis on unique characteristics of subsets of these cells functioning within the respiratory system. The primary sensitization events that generate B cells responsible for effector responses throughout the airways usually occur in the upper airways, tonsils, and adenoid structures that make up the Waldeyer ring. On secondary exposure to antigen in the airways, antigen-processing dendritic cells migrate into secondary lymphoid organs, such as lymph nodes, that drain the upper and lower airways, and further B-cell expansion takes place at those sites. Antigen exposure in the upper or lower airways can also drive expansion of B-lineage cells in the airway mucosal tissue and lead to the formation of inducible lymphoid follicles or aggregates that can mediate local immunity or disease.

Biomarkers of disease and treatment in murine and cynomolgus models of chronic asthma

Background

Biomarkers facilitate early detection of disease and measurement of therapeutic efficacy, both at clinical and experimental levels. Recent advances in analytics and disease models allow comprehensive screening for biomarkers in complex diseases, such as asthma, that was previously not feasible.

Objective

Using murine and nonhuman primate (NHP) models of asthma, identify biomarkers associated with early and chronic stages of asthma and responses to steroid treatment.

Methods

The total protein content from thymic stromal lymphopoietin transgenic (TSLP Tg) mouse BAL fluid was ascertained by shotgun proteomics analysis. A subset of these potential markers was further analyzed in BAL fluid, BAL cell mRNA, and lung tissue mRNA during the stages of asthma and following corticosteroid treatment. Validation was conducted in murine and NHP models of allergic asthma.

Results

Over 40 proteins were increased in the BAL fluid of TSLP Tg mice that were also detected by qRT-PCR in lung tissue and BAL cells, as well as in OVA-sensitive mice and house dust mite-sensitive NHP. Previously undescribed as asthma biomarkers, KLK1, Reg3γ, ITLN2, and LTF were modulated in asthmatic mice, and Clca3, Chi3l4 (YM2), and Ear11 were the first lung biomarkers to increase during disease and the last biomarkers to decline in response to therapy. In contrast, GP-39, LCN2, sICAM-1, YM1, Epx, Mmp12, and Klk1 were good indicators of early therapeutic intervention. In NHP, AMCase, sICAM-1, CLCA1, and GP-39 were reduced upon treatment with corticosteroids.

Conclusions and clinical relevance

These results significantly advance our understanding of the biomarkers present in various tissue compartments in animal models of asthma, including those induced early during asthma and modulated with therapeutic intervention, and show that BAL cells (or their surrogate, induced sputum cells) are a viable choice for biomarker examination.

Recent insights into microbial triggers of interleukin-10 production in the host and the impact on infectious disease pathogenesis

Since its initial description as a Th2-cytokine antagonistic to interferon-alpha and granulocyte-macrophage colony-stimulating factor, many studies have shown various anti-inflammatory actions of interleukin-10 (IL-10), and its role in infection as a key regulator of innate immunity. Studies have shown that IL-10 induced in response to microorganisms and their products plays a central role in shaping pathogenesis. IL-10 appears to function as both sword and shield in the response to varied groups of microorganisms in its capacity to mediate protective immunity against some organisms but increase susceptibility to other infections. The nature of IL-10 as a pleiotropic modulator of host responses to microorganisms is explained, in part, by its potent and varied effects on different immune effector cells which influence antimicrobial activity. A new understanding of how microorganisms trigger IL-10 responses is emerging, along with recent discoveries of how IL-10 produced during disease might be harnessed for better protective or therapeutic strategies. In this review, we summarize studies from the past 5 years that have reported the induction of IL-10 by different classes of pathogenic microorganisms, including protozoa, nematodes, fungi, viruses and bacteria and discuss the impact of this induction on the persistence and/or clearance of microorganisms in the host.

Gene therapy: light is finally in the tunnel

After two decades of ups and downs, gene therapy has recently achieved a milestone in treating patients with Leber's congenital amaurosis (LCA). LCA is a group of inherited blinding diseases with retinal degeneration and severe vision loss in early infancy. Mutations in several genes, including RPE65, cause the disease. Using adeno-associated virus as a vector, three independent teams of investigators have recently shown that RPE65 can be delivered to retinal pigment epithelial cells of LCA patients by subretinal injections resulting in clinical benefits without side effects. However, considering the whole field of gene therapy, there are still major obstacles to clinical applications for other diseases. These obstacles include innate and immune barriers to vector delivery, toxicity of vectors and the lack of sustained therapeutic gene expression. Therefore, new strategies are needed to overcome these hurdles for achieving safe and effective gene therapy. In this article, we shall review the major advancements over the past two decades and, using lung gene therapy as an example, discuss the current obstacles and possible solutions to provide a roadmap for future gene therapy research.

B lymphocytes in inflammatory airway diseases

B lymphocytes are key players in all facets of adaptive immune responses and are responsible for the production of IgE antibodies, initiators of allergic hypersensitivity reactions. Recent evidence indicates that B cells may be a crucial player in allergic and inflammatory airway pathology, directly populating upper and lower airway tissues. This review examines human and animal studies that directly demonstrated the presence of B lymphocytes in airway tissues and elaborates on their function as antibody-secreting cells, antigen-presenting cells and producers of inflammatory and regulatory cytokines. B lymphocytes appear to contribute to multiple facets of immune homeostasis in inflammatory diseases of the upper and lower airways.

Cleavage of SIgA by gram negative respiratory pathogens enhance neutrophil inflammatory potential

OBJECTIVE

Secretory immunoglobulin A (SIgA), the principle immune defense at respiratory and other mucosal sites in the body, is highly dependant on its molecular structure for effective antibody function. Previous studies have demonstrated that gram-negative but not gram-positive isolates from patients with nosocomial pneumonia have IgA protease activity that contributes to the development of infection. We postulate that SIgA cleavage by bacteria would also affect anti-inflammatory properties of IgA and studied this in vitro.

METHODS

Sterile filtrates obtained from Pseudomonas, Acinetobacter, and methicillin resistant Staphylococcus aureus (MRSA) held in culture with SIgA were used to challenge polymorphonuclear neutrophils (PMNs) obtained from healthy volunteers. In a second group of experiments, blood monocytes were incubated with lipopolysaccharide (LPS) or LPS + IgA, and the resulting culture supernatants was used to stimulate PMNs in vitro.

RESULTS

LPS-stimulated monocytes increased CD11b expression, O2-generation and elastase release by PMNs. Secretory IgA but not IgG abrogated this response. Cleavage of SIgA by the gram-negative respiratory isolates, Pseudomonas aeruginosa and Acinetobacter baumanii also led to the loss of cellular effector function noted with intact SIgA. Additionally, PMN cytotoxic potential was similar to that noted with PMNs treated with supernatant from LPS-stimulated monocytes.

CONCLUSION

IgA cleavage by gram-negative respiratory isolates may lead to the development of pneumonia and the subsequent severity of the infection as a result of uncontrolled inflammatory responses by the host.

Alterations in the human lung proteome with lipopolysaccharide

Background

Recombinant human activated protein C (rhAPC) is associated with improved survival in high-risk patients with severe sepsis; however, the effects of both lipopolysaccharide (LPS) and rhAPC on the bronchoalveolar lavage fluid (BALF) proteome are unknown.

Methods

Using differential in gel electrophoresis (DIGE) we identified changes in the BALF proteome from 10 healthy volunteers given intrapulmonary LPS in one lobe and saline in another lobe. Subjects were randomized to pretreatment with saline or rhAPC.

Results

An average of 255 protein spots were detected in each proteome. We found 31 spots corresponding to 8 proteins that displayed abundance increased or decreased at least 2-fold after LPS. Proteins that decreased after LPS included surfactant protein A, immunoglobulin J chain, fibrinogen-γ, α₁-antitrypsin, immunoglobulin, and α₂-HS-glycoprotein. Haptoglobin increased after LPS-treatment. Treatment with rhAPC was associated with a larger relative decrease in immunoglobulin J chain, fibrinogen-γ, α₁-antitrypsin, and α₂-HS-glycoprotein.

Conclusion

Intrapulmonary LPS was associated with specific protein changes suggesting that the lung response to LPS is more than just a loss of integrity in the alveolar epithelial barrier; however, pretreatment with rhAPC resulted in minor changes in relative BALF protein abundance consistent with its lack of affect in ALI and milder forms of sepsis.

Host defenses

Repeated episodes of viral upper respiratory tract infections occur anywhere from four to eight times per year in healthy individuals Local and systemic defense mechanisms exist to battle respiratory tract pathogens. Clinical manifestations are mainly due to host inflammatory response. Unfortunately, the host defense mechanisms are very often not sufficient to prevent subsequent/repeated episodes of infections(s). Further insight into the interaction of infectious agent and host immune response, genetic factors, and environmental factors is needed for a better understanding of why humans repeatedly and frequently suffer from infections with respiratory agents and develop a disease syndrome known as common cold.

Intranasal immunization with Naegleria fowleri lysates and Cry1Ac induces metaplasia in the olfactory epithelium and increases IgA secretion

According to previous reports, intranasal administration of the Cry1Ac protein alone or with amoebic lysates increases protection against Naegleria fowleri meningoencephalitis in mice, apparently by eliciting IgA responses in the nasal mucosa. In the current study, we performed an immunohistochemical analysis of IgA in the nasal mucosa of mice immunized intranasally with Cry1Ac, and amoebic lysates or a combination of both. The animals were sacrificed 24 h after the last immunization or after an intranasal lethal challenge with N. fowleri. Our results indicate that all of the intranasal immunizations provoked an increase in areas with metaplasia in the olfactory epithelium, allowing for secretion of IgA. As a result, IgA antibodies were found interacting with trophozoites in the nasal lumen, and there was a marked increase of IgA in the metaplasic epithelium. On the other hand in nonimmunized mice trophozoites were observed invading the nasal mucosa, which was not the case for immunized mice. Our results suggest that intranasal immunization provokes cellular changes in the olfactory epithelium, leading to greater protection against N. fowleri that is probably caused by an increased secretion of IgA. The increased IgA response induced in the nasal mucosa by immunization probably impedes both amoebic adhesion and subsequent invasion of the parasite to the nasal epithelium.

Beyond inflammation: airway epithelial cells are at the interface of innate and adaptive immunity

It has become increasingly clear that airway epithelial cells are central participants in innate and adaptive immune responses as well as mucosal inflammation. Epithelial cells produce antimicrobial host defense molecules, proinflammatory cytokines and chemokines in response to activation via pathogen recognition receptors. Recruitment of immune cells including dendritic cells, T cells and B cells into the proximity of epithelium results in the enhancement of adaptive immunity through interactions with epithelial cells. Newly identified epithelial-derived cytokines, including TSLP, IL-33 and BAFF, help to shape the local accumulation and activation of Th2 responses and B cell immunoglobulin production. Epithelial cells are also downstream targets of molecules that activate IL-13R and EGFR and are responsible for mucus production in both protective immune responses and allergic airway inflammatory diseases. Improved understanding of epithelial immune and inflammatory responses will hopefully suggest new strategies for therapeutic intervention.

The anti-inflammatory properties of cocoa flavanols

Signs of chronic or acute inflammation have been demonstrated in most cardiovascular diseases of multifactorial pathogenesis, including atherosclerosis and chronic heart failure. The triggers and mechanisms leading to inflammation may vary between clinical conditions but they share many common mediators, including specific patterns of eicosanoid and cytokine production. Certain cocoa-based products can be rich in a subclass of flavonoids known as flavanols, some of which have been found in model systems to possess potential anti-inflammatory activity relevant to cardiovascular health. Indeed, experimental evidence demonstrates that some cocoa-derived flavanols can reduce the production and effect of pro-inflammatory mediators either directly or by acting on signaling pathways. However, it should be noted that the evidence for any beneficial effects of cocoa flavanols in providing a meaningful anti-inflammatory action has been gathered predominantly from in vitro experiments. Therefore, additional research in well-designed human clinical experiments, using cocoa properly characterized in terms of flavanol content, would be a welcome addition to the evidence base to determine unambiguously if this benefit does indeed exist. If so, then flavanol-rich cocoa could be a potential candidate for the treatment, or possibly prevention, of the broad array of chronic diseases that are linked to dysfunctional inflammatory responses.

T-cell independent production of salivary secretory IgA after hematopoietic stem cell transplantation in children

This study examined the recovery of secretory IgA (S-IgA) in saliva after hematopoietic stem cell transplantation (HSCT) in 35 children and young people between the ages of 3 and 27 years (mean=13.6), and compared this recovery with that of serum immunologic constituents. Reference values for human salivary S-IgA in saliva were obtained from 77 healthy control subjects between the ages of 7 and 25 years (mean=11.4). In the 35 patients, a nadir of secretory IgA concentrations in saliva (S-IgA) was observed between the 3rd and the 4th month, and a return to normal values 1 year after HSCT. Serum IgA concentrations reached their nadir in the 6th month, and normalized in the 18 months after HSCT. The recovery of T-helper cells (CD4+/3+) was also delayed to beyond 18 months. We found a significant correlation between the reconstitution pattern of S-IgA and that of T-helper lymphocytes, but no correlation was found between the post-transplant evolutions of S-IgA and serum IgA, or between S-IgA and T-helper cells. The recovery of S-IgA was more rapid than that of serum IgA and appeared to be T-helper cell independent.

Distribution of leucocyte subsets in the canine respiratory tract

Histochemistry and immunohistochemistry were used to characterize leucocyte subsets in the respiratory tract of 15 outbred dogs (five aged <6 months and 10 aged >1 year) that had no evidence of respiratory disease. No organized nose- or bronchus-associated lymphoid tissue was observed in any of the sections examined. IgA(+) plasma cells predominated in nasal mucosa and in all parts of the bronchial tree, with fewer IgG(+) and IgM(+) plasma cells. The numbers of IgA(+) and IgM(+) cells were significantly greater in the nasal mucosa than in any other part of the respiratory mucosa. There were significantly fewer IgA(+), IgG(+) and IgM(+) cells in all parts of the respiratory tract in the puppies than in the adults. The number and distribution of mast cells and cells expressing MHC class II, L1 or CD1c were recorded. Mast cells were mainly found in the subepithelial lamina propria of nasal and bronchial mucosa and in the alveolar interstitium, and cells expressing IgE had a similar distribution. Mast cells were also present within muscle layers of the bronchial tree. The numbers of mast cells and MHC class II(+) cells were significantly greater in the nasal mucosa than in any other part of the respiratory mucosa. In the nose, carina and primary and secondary bronchus, there were significantly more mast cells and MHC class II(+) cells in puppies than in adult dogs, whereas the numbers of L1(+) cells and CD1c(+) cells in most sites were significantly greater in older dogs. There were significantly more CD3(+) and CD8(+) cells in the nasal mucosa than in any part of the bronchial mucosa. In most parts of the respiratory mucosa, CD4(+), CD8(+) and TCR alphabeta(+) cells were present in significantly greater numbers in adults than in puppies. All parts of the respiratory tract had similar numbers of mucosal CD4(+) and CD8(+) T lymphocytes. TCR gammadelta(+) cells were absent or sparse in all samples. These data, obtained from dogs without respiratory disease, will enable comparisons to be made with dogs suffering from infectious or inflammatory nasal, bronchial and pulmonary diseases.

The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion

Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.

PLGA-PEI nanoparticles for gene delivery to pulmonary epithelium

Pulmonary gene delivery is thought to play an important role in treating genetically related diseases and may induce immunity towards pathogens entering the body via the airways. In this study we prepared poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles bearing polyethyleneimine (PEI) on their surface and characterized them for their potential in serving as non-viral gene carriers to the pulmonary epithelium. Particles that were synthesized at different PLGA–PEI ratios and loaded with DNA in several PEI–DNA ratios, exhibited narrow size distribution in all formulations, with mean particle sizes ranging between 207 and 231 nm. Zeta potential was strongly positive (above 30 mV) for all the PEI–DNA ratios examined and the loading efficiency exceeded 99% for all formulations. Internalization of the DNA-loaded PLGA–PEI nanoparticles was studied in the human airway submucosal epithelial cell line, Calu-3, and DNA was detected in the endo-lysosomal compartment 6 h after particles were applied. Cytotoxicity of these nanoparticles was dependent on the PEI–DNA ratio and best cell viability was achieved by PEI–DNA ratios 1:1 and 0.5:1. These findings demonstrate that PLGA–PEI nanoparticles are a potential new delivery system to carry genes to the lung epithelium.

Salivary antibodies directed against outer membrane proteins of Moraxella catarrhalis in healthy adults

Moraxella catarrhalis is a major mucosal pathogen of the human respiratory tract, but the mucosal immune response directed against surface components of this organism has not been characterized in detail. The aim of this study was to investigate the salivary immunoglobulin A (IgA) response toward outer membrane proteins (OMP) of M. catarrhalis in healthy adults, the group of individuals least likely to be colonized and thus most likely to display mucosal immunity. Unstimulated saliva samples collected from 14 healthy adult volunteers were subjected to IgA immunoblot analysis with OMP preparations of M. catarrhalis strain O35E. Immunoblot analysis revealed a consistent pattern of IgA reactivity, with the appearance of five major bands located at >250, 200, 120, 80, and 60 kDa. Eleven (79%) of 14 saliva samples elicited reactivity to all five bands. Immunoblot analysis with a set of isogenic knockout mutants lacking the expression of individual OMP was used to determine the identities of OMP giving rise to IgA bands. Human saliva was shown consistently to exhibit IgA-binding activity for oligomeric UspA2 (>250 kDa), hemagglutinin (200 kDa), monomeric UspA1 (120 kDa), transferrin-binding protein B (TbpB), monomeric UspA2, CopB, and presumably OMP CD. TbpB, oligomeric UspA2, and CopB formed a cluster of bands at about 80 kDa. These data indicate that the human salivary IgA response is directed consistently against a small number of major OMP, some of which are presently considered vaccine candidates. The functional properties of these mucosal antibodies remain to be elucidated.

Transcytosis: crossing cellular barriers

Transcytosis, the vesicular transport of macromolecules from one side of a cell to the other, is a strategy used by multicellular organisms to selectively move material between two environments without altering the unique compositions of those environments. In this review, we summarize our knowledge of the different cell types using transcytosis in vivo, the variety of cargo moved, and the diverse pathways for delivering that cargo. We evaluate in vitro models that are currently being used to study transcytosis. Caveolae-mediated transcytosis by endothelial cells that line the microvasculature and carry circulating plasma proteins to the interstitium is explained in more detail, as is clathrin-mediated transcytosis of IgA by epithelial cells of the digestive tract. The molecular basis of vesicle traffic is discussed, with emphasis on the gaps and uncertainties in our understanding of the molecules and mechanisms that regulate transcytosis. In our view there is still much to be learned about this fundamental process.

Effect of cocoa flavanols and their related oligomers on the secretion of interleukin-5 in peripheral blood mononuclear cells

We previously showed that flavanols and their related oligomers (FLO) isolated from cocoa can have immunomodulatory effects on production of the cytokines interleukin-1beta (IL-1beta), IL-2, and IL-4. In the present study, we examined whether selected FLO fractions isolated from cocoa (monomer through decamer) modulate IL-5 protein secretion from resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). Although FLO fractions were unstimulatory for IL-5 secretion in resting cells, PHA-induced IL-5 release from PBMC was markedly affected by certain FLO fractions. The monomeric and small oligomeric (dimer and trimer) fractions enhanced PHA stimulation by 50%, 54%, and 43%, respectively. In contrast, the larger oligomeric fractions (hexamer through decamer) inhibited IL-5 release in the range of 18% to 39%; the tetramer and pentamer showed intermediate effects. The increment in IL-5 suggests that FLO may preferentially stimulate immunoglobulin A. We suggest that in the oral cavity this could result in reduction in the risk for dental caries and periodontal disease. This work offers additional data for consideration of the health benefits of dietary FLO from a variety of foods, including those benefits associated specifically with consumption of some cocoas and chocolates.

B- and T-cell responses to the mycobacterium surface antigen PstS-1 in the respiratory tract and adjacent tissues. Role of adjuvants and routes of immunization

Induction of mucosal immunity in the respiratory tract is crucial for protection against respiratory infections. Here, we have investigated the effects of the routes of immunization as well as of three different adjuvants on the induction of mucosal immune responses. Mice were immunized using intranasal (i.n.) or intraperitoneal (i.p.) routes with the mycobacterium PstS-1 antigen. Cholera toxin (CT), detoxified pertussis toxin (detPT) and RU 41.740 from Klebsiella pneumoniae were compared as mucosal adjuvants. Our data showed that i.n. route of immunization induced the most favorable stimulation of mucosal antigen-specific IgA responses supported by mixed Th cells producing IL-4, IL-5, IFN-gamma. In contrast, i.p. immunizations elicited only enhancement of systemic responses, predominantly of the Th2 type. Furthermore, the use of CT as mucosal adjuvant resulted in the stimulation of a mixed Th cell response whereas detPT evoked mainly Th2 type of responses. Likewise CT, the RU 41.740 adjuvant elicited a mixed Th cell response, albeit supported by much lower numbers of CD4(+) T-cells. Thus, i.n. route of immunization favors the induction of mucosal and systemic immune responses, while the Th cell development at mucosal inductive site is influenced by the adjuvant used for immunizations.

[BK channels play an important role as a negative feedback mechanism in the regulation of spontaneous rhythmic contraction of urinary bladder smooth muscles]

Smooth muscles of urinary bladder wall exhibit spontaneous rhythmic contraction which is myogenic in origin. Although the precise mechanism responsible for the generation of this mechanical activity remains to be established, it can be related closely to the action potential (AP) in urinary bladder smooth muscle (UBSM) cell, and may be the fundamental constituent to determine urinary bladder physiological functions to store and micturate urine. In the present study, possible roles of voltage-dependent and Ca(2+)-sensitive K+ (BK) channels, highly expressed in UBSM cells, were examined in the regulation of spontaneous UBSM contraction with reference to the generation of AP. Iberiotoxin (IbTx), a selective BK channel blocker, strongly increased mechanical activity and AP generation in guinea-pig UBSM. In contrast, BK channel openers (NS-1619, niflumic acid; estradiol, tamoxifen: BK channel alpha- and beta-subunit activators, respectively) significantly diminished AP generation and spontaneous mechanical activity. The present study indicates that BK channels play the primary role as a negative feedback element to limit extracellular Ca2+ influx through affecting AP configurations in the generation of UBSM contraction. BK channel openers including beta-subunit activators may be a potentially useful therapeutic remedy for the treatment of urinary bladder dysfunctions such as frequent urination.

Mucosal immunology: overview and potential in the veterinary species

A large part of the immune system is dedicated to protection from infection at mucosal surfaces. The concept of the common mucosal immune system has been investigated in several veterinary species where traffic of mucosally activated lymphocytes from induction to effector sites has been demonstrated. The dominant isotype found in secretions of the upper respiratory tract and gut of normal healthy and diseased animals is IgA. B lymphocytes have a relatively short half-life and there is continuous production of IgA at these sites, which is achieved by constant secretion from T helper and epithelial cells of cytokines that are critical for B cell maturation and IgA secretion. Specific stimulation of mucosal immune responses using intranasal presentation of live and inactivated antigens (with adjuvants active at mucosal surfaces) has shown great promise for inducing protective immunity to respiratory pathogens.

Pulmonary defences to acute respiratory infection

Of all sites in the body, the lung is perhaps challenged by the greatest onslaught of microbial pathogens, many of which would cause lethal infections if unopposed. The immune response to respiratory infection must, therefore, be rapid and efficient. However, the respiratory tract is a fragile tissue with architecture that is finely designed for gas exchange, so that the price of excessive or inappropriate inflammatory responses may itself be very high. The first line of defence comes from barriers such as mucus and cilia, followed by a battery of mediators that constitute the innate response. These include lactoferrin, lysozyme, collectins and defensins. Activation of these molecules can lead directly to lysis of pathogens, or to destruction through opsonisation or the recruitment of inflammatory cells. The adaptive immune response includes the production of neutralising antibodies and the responses of T lymphocytes. Different populations of T lymphocytes may dramatically alter the balance between clearance of the pathogen and induction of tissue damage depending on the cytokines they secrete.