Listeriolysin O derived from Listeria monocytogenes inhibits the effector phase of an experimental allergic rhinitis induced by ovalbumin in mice

Augmented type 2 inflammatory response in allergic rhinitis patients experiencing systemic reactions to house dust mite subcutaneous immunotherapy

BACKGROUND

Subcutaneous immunotherapy (SCIT) can induce systemic reactions (SRs) in certain patients, but the underlying mechanisms remain to be fully elucidated.

METHODS

AR patients who were undergoing standardized HDM SCIT (Alutard, ALK) between 2018 and 2022 were screened. Those who experienced two consecutive SRs were included in the study group. A control group was established, matched 1:1 by gender, age, and disease duration with the study group, who did not experience SRs during SCIT. Clinical and immunological parameters were recorded and analyzed both before SCIT and after 1 year of treatment.

RESULTS

A total of 161 patients were included, with 79 (49.07%) in the study group. The study group had a higher proportion of AR combined asthma (26.8% vs. 51.8%, p < 0.001) and higher levels of sIgE to HDM and HDM components (all p < .001). Serum IL-4 and IL-13 levels in the study group were higher than those in the control group (p < .05). The study group received a lower maintenance dosage of HDM extracts injections than control group due to SRs (50000SQ vs. 100000SQ, p < .05). After 1 year of SCIT, the VAS score, the lung function parameters of asthmatic patients over 14 years old significantly improved in both groups (all p < .05). After a 7-day exposure to 20 μg/mL HDM extracts, the percentages of Th1, Th17, Tfh10, and Th17.1 in PBMCs decreased, while the Tfh13 cells significantly increased in the study group (p < .05).

CONCLUSION

The type 2 inflammatory response is augmented in HDM-induced AR patients who experienced SRs during SCIT. Despite this, SCIT remains effective in these patients when administered with low-dosage allergen extracts.

TiO2-DNA Nanosensor In Situ for Quick Detection of Nasal Flora in Allergic Rhinitis Patients

Background

A relevant study found that allergic rhinitis (AR) may be related to the imbalance of nasal flora. Therefore, if the nasal flora of AR patients can be detected quickly, it is of great significance to study the distribution law of nasal flora in AR patients and explore its correlation with AR.

Objective

To design a new and convenient nano-DNA sensor for quick screening of nasal flora in allergic rhinitis (AR) patients, so as to provide experimental basis for the prevention and treatment of AR.

Methods

We create a synthesized nanostructured DNA biosensor called Nano-TiO₂-DNA sensor which can be combined with samples from nasal mucosa or secretion with high efficiency and detect certain flora in situ without DNA extraction or RNA sequencing. In a physical property test, firstly, we tested the permeability, solubility, and storage temperature of nano-TiO₂, so as to provide experimental basis for the synthesis of Nano-TiO₂-DNA sensor. Subsequently, the permeability of Nano-TiO₂-DNA sensor in Staphylococcus aureus was further tested. In a clinical experiment, we selected 60 AR patients treated in our hospital from September 2020 to September 2021 as the AR group and 60 healthy people who underwent physical examination at the same time as the control group. The Nano-TiO₂-DNA sensor was used to detect typical nasal flora in AR patients, and Pearson's correlation analysis was used to explore the correlation between nasal flora with serum IgE and eosinophils.

Results

As for physicochemical characteristics, this sensor can permeate into certain bacteria directly and specifically. It has high affinity ability with a target, and the combination can be detected by evaluating the released fluorescence qualitatively and quantitatively. It can be stored at −20°C in ethyl alcohol stably. By this sensor, we have successfully detected Staphylococcus aureus, Klebsiella pneumoniae, and viridans streptococci in AR patients compared with healthy people, which will help these patients in the prevention of acute sinusitis and acute or subacute pneumonia. Furthermore, we found Proteus had the strongest positive correlation with AR while Actinomyces had the biggest negative correlation.

Conclusion

The Nano-TiO₂-DNA sensor will help an outpatient doctor more for quick screening certain nasal flora in AR patients and improve the prevention of AR-related complications.

Shin'iseihaito (Xinyiqingfeitang) extract ameliorates ovalbumin-induced murine allergic rhinitis by regulating cytokines

Shin'iseihaito (Xinyiqingfeitang) is a formula of traditional Japanese Kampo medicine and traditional Chinese medicine (TCM) and for chronic sinusitis. However, the precise action mechanism has been unknown. We examined the effect of shin'iseihaito extract (SSHT) on murine allergic rhinitis model using ovalbumin (OVA). We decocted the mixture of 9 crude drugs in water to prepare SSHT. SSHT (20 times amount of human dose) was orally administered to mice treated with OVA. After mice were sacrificed on day 28, immunoglobulin (Ig) E, interleukin (IL)-4, IL-13, interferon (IFN)-γ, and thymic stromal lymphopoietin (TSLP) levels in nasal lavage fluid samples were measured by enzyme-linked immunosorbent assay (ELISA). The pathological tissue sections from the nasal epithelial mucosa were histopathologically investigated by optical and scanning electron microscopies. We also investigated the effects of modified SSHTs prepared by removing one crude drug from shin'iseihaito to clarify the active ingredients. SSHT suppressed IgE, IL-4, IL-13, and TSLP levels, while increased the IFN-γ levels in OVA-induced allergic mice. Sensitization with OVA resulted in an increase in eosinophilia and goblet cells in murine nasal cavity tissue in comparison with those in untreated group, however, those were significantly reduced by the treatment with SSHT. The extracts of 8 crude drug's mixtures except for the removal of Gypsum fibrosum (GF) from shin'iseihaito counteracted on the suppressive effects of SSHT on IgE, IL-4, IL-13, and TSLP levels in nasal lavage fluid. Our result demonstrated that SSHT may contribute to inhibit the exacerbation of OVA-induced murine allergic rhinitis by regulating cytokines, and the components except for GF contributed anti-allergic effect of shin'iseihaito.

TLR2 Regulates Mast Cell IL-6 and IL-13 Production During Listeria monocytogenes Infection

Listeria monocytogenes (L.m) is efficiently controlled by several cells of the innate immunity, including the Mast Cell (MC). MC is activated by L.m inducing its degranulation, cytokine production and microbicidal mechanisms. TLR2 is required for the optimal control of L.m infection by different cells of the immune system. However, little is known about the MC receptors involved in recognizing this bacterium and whether these interactions mediate MC activation. In this study, we analyzed whether TLR2 is involved in mediating different MC activation responses during L.m infection. We found that despite MC were infected with L.m, they were able to clear the bacterial load. In addition, MC degranulated and produced ROS, TNF-α, IL-1β, IL-6, IL-13 and MCP-1 in response to bacterial infection. Interestingly, L.m induced the activation of signaling proteins: ERK, p38 and NF-κB. When TLR2 was blocked, L.m endocytosis, bactericidal activity, ROS production and mast cell degranulation were not affected. Interestingly, only IL-6 and IL-13 production were affected when TLR2 was inhibited in response to L.m infection. Furthermore, p38 activation depended on TLR2, but not ERK or NF-κB activation. These results indicate that TLR2 mediates only some MC activation pathways during L.m infection, mainly those related to IL-6 and IL-13 production.

A Novel Approach for Investigating Upper Airway Hyperresponsiveness Using Micro-CT in Eosinophilic Upper Airway Inflammation such as Allergic Rhinitis Model

Airway hyperresponsiveness (AHR) has been proposed as a feature of pathogenesis of eosinophilic upper airway inflammation such as allergic rhinitis (AR). The measurement system for upper AHR (_UAHR) in rodents is poorly developed, although measurements of nasal resistance have been reported. Here we assessed UAHR by direct measurement of swelling of the nasal mucosa induced by intranasal methacholine (MCh) using micro-computed tomography (micro-CT). Micro-CT analysis was performed in both naïve and ovalbumin-induced AR mice following intranasal administration of MCh. The nasal cavity was segmented into two-dimensional horizontal and axial planes, and the data for nasal mucosa were acquired for the region of interest threshold. Then, a ratio between the nasal mucosa area and nasal cavity area was calculated as nasal mucosa index. Using our novel method, nasal cavity structure was clearly identified on micro-CT, and dose-dependent increased swelling of the nasal mucosa was observed upon MCh treatment. Moreover, the nasal mucosa index was significantly increased in AR mice compared to controls following MCh treatment, while ovalbumin administration did not affect swelling of the nasal mucosa in either group. This UAHR following MCh treatment was completely reversed by pretreatment with glucocorticoids. This novel approach using micro-CT for investigating UAHR reflects a precise assessment system for swelling of the nasal mucosa following MCh treatment; it not only sheds light on the mechanism of AR but also contributes to the development of new therapeutic drugs in AR patients.

Effect of Shin'iseihaito on murine allergic reaction induced by nasal sensitization

Shin'iseihaito (Magnolia Flower Lung-Clearing Decoction; 辛夷清肺湯 xīn yí qīng fèi tāng), a formula of traditional Japanese kampo medicine (日本漢醫 rì běn hàn yī) and traditional Chinese medicine (TCM; 中醫 zhōng yī), has been used for the treatment of chronic sinusitis. The objective of this study was to evaluate the anti-allergic effect of shin'iseihaito on murine allergic reaction induced by nasal sensitization using ovalbumin (OVA) as an antigen. Extract of shin'iseihaito (SSHT) could reduce the eosinophil, serum IgE and interleukin (IL)-4 levels, while increased the interferon (IFN)-γ levels in allergic mouse. Furthermore, allergic-murine serum treated with SSHT could not activate passive cutaneous anaphylaxis (PCA) reaction in murine model. Thus, our study showed that SSHT may possess anti-allergic activity. We suggested that SSHT may contribute to inhibit the exacerbation of allergic reaction induced by nasal sensitization.

Biological effects of listeriolysin O: implications for vaccination

Listeriolysin O (LLO) is a thiol-activated cholesterol-dependent pore-forming toxin and the major virulence factor of Listeria monocytogenes (LM). Extensive research in recent years has revealed that LLO exerts a wide array of biological activities, during the infection by LM or by itself as recombinant antigen. The spectrum of biological activities induced by LLO includes cytotoxicity, apoptosis induction, endoplasmic reticulum stress response, modulation of gene expression, intracellular calcium oscillations, and proinflammatory activity. In addition, LLO is a highly immunogenic toxin and the major target for innate and adaptive immune responses in different animal models and humans. Recently, the crystal structure of LLO has been published in detail. Here, we review the structure-function relationship for this fascinating microbial molecule, highlighting the potential uses of LLO in the fields of biomedicine and biotechnology, particularly in vaccination.

Development of a Listeria monocytogenes-based vaccine against hepatocellular carcinoma

Live attenuated Listeria monocytogenes (LM) is a promising bacterial vector able to induce a T-cell response to tumor-associated antigens and demonstrates great potential for use in vaccine development. A novel recombinant LM-based vaccine (Lmdd (LM ΔdalΔdat)-MPFG (multiple peptide fusing genes)) was developed with the ability to express and secrete hepatocellular carcinoma (HCC)-related tumor-associated antigens fragments due to the insertion of hepatitis B virus (HBV)-X protein (HBx)-derived epitopes HBx(52-60) and HBx(140-148), the universal T-helper epitope, alpha-fetoprotein (AFP) epitope AFP(158-166), and melanoma antigen gene (MAGE)-3(271-279) into the HBV core protein. Following immunization with the Lmdd-MPFG vaccine, macrophages exhibited uptake of the bacteria; the vaccine was then nearly cleared 3 days after the first administration. It disappeared even more quickly following subsequent vaccinations. However, recombinant Lmdd-MPFG allowed for the full development of an antitumor response towards the human leukocyte antigen (HLA)-A0201 epitopes of MPFG. Each epitope stimulated an augmented T-cell proliferation and enhanced the supernatant level of interferon (IFN)-γ in vitro. In addition, IFN-γ-producing CD8(+) T cells as well as in vivo cytolytic activity were significantly increased in HLA-A2 transgenic mice. Additionally, the Lmdd-MPFG developed a strong antitumor response, as indicated by the significant resistance of immunized mice to MPFG-positive Hepa1-6 cell challenge in both a prophylactic and therapeutic setting. Tumor regression was accompanied by an enhanced cytotoxic T lymphocyte response and a decrease of regulatory T cells in the tumor. Collectively, these results suggest that utilizing attenuated LM as a vaccine vector, able to carry the MPFG gene, presents a potentially feasible strategy for prevention of HCC.

Multiple effector mechanisms induced by recombinant Listeria monocytogenes anticancer immunotherapeutics

Listeria monocytogenes is a facultative intracellular gram-positive bacterium that naturally infects professional antigen presenting cells (APC) to target antigens to both class I and class II antigen processing pathways. This infection process results in the stimulation of strong innate and adaptive immune responses, which make it an ideal candidate for a vaccine vector to deliver heterologous antigens. This ability of L. monocytogenes has been exploited by several researchers over the past decade to specifically deliver tumor-associated antigens that are poorly immunogenic such as self-antigens. This review describes the preclinical studies that have elucidated the multiple immune responses elicited by this bacterium that direct its ability to influence tumor growth.

Bacterial toxins as immunomodulators

Bacterial toxins are the causative agent at pathology in a variety of diseases. Although not always the primary target of these toxins, many have been shown to have potent immunomodulatory effects, for example, inducing immune responses to co-administered antigens and suppressing activation of immune cells. These abilities of bacterial toxins can be harnessed and used in a therapeutic manner, such as in vaccination or the treatment of autoimmune diseases. Furthermore, the ability of toxins to gain entry to cells can be used in novel bacterial toxin based immuno-therapies in order to deliver antigens into MHC Class I processing pathways. Whether the immunomodulatory properties of these toxins arose in order to enhance bacterial survival within hosts, to aid spread within the population or is pure serendipity, it is interesting to think that these same toxins potentially hold the key to preventing or treating human disease.

Rosiglitazone attenuates allergic inflammation and inhibits expression of galectin-3 in a mouse model of allergic rhinitis

Peroxisome proliferator activated receptor gamma (PPAR-gamma) agonists are involved in the regulation of inflammatory responses and recent studies suggest that PPAR-gamma ligands may have potential for the treatment of allergic airway disease. This study investigated the effect of the PPAR-gamma agonist, rosiglitazone, on nasal mucous allergic inflammation and galectin-3 gene expression in a murine model of allergic rhinitis (AR mice). Rosiglitazone resulted in a statistically significant attenuation of the increased numbers of inflammatory cells and Th2 cytokine levels in nasal cavity lavage fluid of AR mice. Furthermore, the expression of galectin-3 in the nasal mucosa of AR mice was statistically significantly increased. Overexpression of galectin-3 was markedly suppressed by rosiglitazone treatment. These data suggest that the PPAR-gamma agonist, rosiglitazone, may have potential in the development of therapies for allergic rhinitis.

Noninvasive system for evaluating allergen-induced nasal hypersensitivity in murine allergic rhinitis

Until now there has been no method for physiologically evaluating nasal hypersensitivity in mice. Enhanced pause (Penh) has been used as an indicator that reflects changes in the lower airway. Recently, however, there is disagreement regarding the significance of the Penh system; this is because Penh is not essentially a physiological parameter, and it might not necessarily represent a change in the lower respiratory tract. The purpose of the present study is to investigate whether Penh could be applicable for analyzing nasal hypersensitivity in mice. BALB/c mice were sensitized with ovalbumin (OVA) through a combination of intraperitoneal injection and daily intranasal challenge in an awake condition. Penh was measured at each time point during sensitization, or a serial change in Penh value was followed after the final nasal challenge and the effect of treatment was assessed. Following sensitization and nasal challenge, the Penh value gradually increased and showed a significant difference on day 14. Changes in IgE, eosinophil infiltration into nasal mucosa, and OVA-induced symptoms all strongly correlated with the increase in Penh. On day 19, after OVA nasal provocation, Penh gradually increased and reached maximal values 25 min after the challenge. Pretreatment with dexamethasone or a histamine H1 blocker significantly suppressed this increase in Penh. We confirmed that intranasal OVA challenge did not induce bronchoconstriction by measuring airway resistance and bronchoalveolar lavage fluid, and through histological examination. These results clearly demonstrate that Penh could be a useful noninvasive indicator for studying nasal hypersensitivity.