Heat shock protein X purified from Mycobacterium tuberculosis enhances the efficacy of dendritic cells-based immunotherapy for the treatment of allergic asthma

Intradermal co-inoculation of codon pair deoptimization (CPD)-attenuated chimeric porcine reproductive and respiratory syndrome virus (PRRSV) with Toll like receptor (TLR) agonists enhanced the protective effects in pigs against heterologous challenge

The objective of this study was to assess protective efficacy of vaccination using CPD-attenuated chimeric PRRSV and Toll like receptor (TLR) agonists (HSP70 c-terminal domain and HSPX) as adjuvants through different inoculation routes. In this study, a chimeric PRRSV composed of two field isolates was synthesized and attenuated by CPD in NSP1 as described in the previous study. The infection of the CPD-attenuated chimeric PRRSV to pigs of 3 weeks-old showed no clinical signs without pathological lesions in necropsy, while it induced improved cross immunity between its parent strains. The TLR agonists were expressed in E. coli and purified to be used. In challenge experiment, pigs of 3 weeks-old were vaccinated using the CPD-attenuated chimeric virus with the prepared TLR agonists through intramuscular or intradermal route, following heterologous challenge after 4 weeks of vaccination. In results, intramuscular or intradermal inoculation of the CPD-attenuated chimeric virus demonstrated excellent protective efficacy against heterologous challenges. Importantly, intradermal inoculation with the TLR agonists enhanced protective effects as shown in the significantly increased level of PRRSV-specific IFN-γ-SCs and cytokines in sera, and the significant reduction of pathological lesion and viral load in lung. This study suggested that the intradermal inoculation of CPD-attenuated chimeric PRRSV plus TLR agonists should be more effective for protection of pigs against diverse PRRS field viruses.

Inhalation of nebulized Mycobacterium vaccae can protect against allergic bronchial asthma in mice by regulating the TGF-β/Smad signal transduction pathway

Background

Mycobacterium vaccae nebulization imparted protective effect against allergic asthma in a mouse model. The TGF-β/Smad signal transduction pathway plays an important role in allergic bronchial asthma. However, the effect of M. vaccae nebulization on the TGF-β/Smad signal transduction pathway in mouse models of allergic asthma remains unclear. This study investigated the preventive effect of M. vaccae nebulization during bronchial asthma in a mouse model and elucidate the implication of TGF-β/Smad signal transduction pathway in the process.

Methods

In total, 24 female Balb/c mice were randomized to normal control (group A), asthma control (group B), and M. vaccae nebulization (group C) groups. Both groups B and C were sensitized using ovalbumin for establishment of the asthmatic model; group A received phosphate-buffered solution. Prior to the establishment of asthma, Group C was nebulized with M. vaccae. Airway responsiveness was measured in all the groups, using a noninvasive lung function machine before and 24 h after establishment of the asthmatic model. The animals were then harvested, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The total cell counts in BALF was estimated. Protein expression of TGF-β1, TβR1, Smad1, and Smad7 was detected by immunohistochemistry. The population of CD3⁺γδT, IL-13⁺CD3⁺T, TGF-β⁺CD3⁺T, IL-13⁺CD3⁺γδT, and TGF-β⁺ CD3⁺ γδT cells were detected by flow cytometry. One-way analysis of variance for within-group comparisons, the least significant difference t-test or Student–Newman–Keuls test for intergroup comparisons, and the nonparametric rank sum test for analysis of airway inflammation scores were used in the study.

Results

The eosinophil count; protein expression of TGF-β1, TβR1, and Smad1; and percentages of CD3⁺γδT and IL-13⁺CD3⁺T cells were significantly lower in the M. vaccae nebulization group than in the asthma control group (P < 0.01). There were significant intergroup differences in the percentages of TGF-β⁺CD3⁺T and IL-13⁺CD3⁺γδT cells (P < 0.05).

Conclusions

Mycobacterium vaccae nebulization could confer protection against allergic bronchial asthma by reducing airway responsiveness and alleviating airway inflammation in mice. The underlying mechanism might be attributed its effect on the deregulated expression of TGF-β1, TβR1, Smad1, and Smad7 of the TGF-β/Smad signal transduction pathway.

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.

Progressive increase in allergen concentration abrogates immune tolerance in ovalbumin-induced murine model of chronic asthma

Persistent inflammation and remodeling of airways are the major hallmarks of asthma. Though airway inflammation diminishes in ovalbumin (OVA)-based mouse model of chronic asthma owing to immune-tolerance linked with repeated allergen exposure, which limits the application of the disease model. Accordingly, the present study was designed to develop a murine model of chronic asthma which presents persistent airway inflammation coupled with remodeling traits. Herein, OVA-sensitized BALB/c mice were challenged with increasing (modified protocol) or constant concentration (conventional protocol) of the allergen for 6 weeks; 3 times/week. The results, indeed, revealed that mice subjected to modified protocol demonstrate an improved response to the allergen as reflected by the significant increase in inflammatory cells particularly, eosinophils in bronchoalveolar lavage fluid compared to conventional protocol. Moreover, the expression of Th2 cytokines and their responsible transcription factors (GATA-3 and STAT-6) was markedly enhanced in lungs. The increase in inflammation was further accompanied by a marked increase in mucus production, collagen deposition, and the expression of allied factors (Muc5ac, Col1α1, and α-SMA). Interestingly, pre-treatment of dexamethasone, a corticosteroid (0.5 mg/kg b.wt., i.p.), suppressed the allergen-induced airway inflammation and mucus production without altering collagen deposition. Failure of dexamethasone seems to be related to their ineffectiveness to modulate the expression of TGF-β, MMP-9, COL1α1, and α-SMA. Overall, our results strongly suggest that mice underwent modified chronic protocol bears more resemblance with asthmatics as it imitates persistent airway inflammation allied with steroid-refractory remodeling traits; hence, may be useful for the evaluation of new/alternative drugs in steroid-refractory asthmatic conditions.

Effect of vitamin D3 on maturation and antigen-presenting function of dendritic cells treated with Mycobacterium tuberculosis

OBJECTIVE

To investigate the phenotypic characteristics and functional capability differences of mouse bone marrow-derived dendritic cells after stimulation with Mycobacterium tuberculosis in the presence or absence of vitamin D3.

METHODS

Mouse bone marrow-derived cells were cultured with GM-CSF (20 ng/mL). Then, one was added with 100 nmol/L of 25(OH)D3, while the other did not. On day 6, 5 μg/mL of BCG was added to stimulate the cells for 24 h. On day 7, suspension cells were harvested for phenotypic and functional analyses.

RESULTS

The percentages of CD86 dendritic cells (DCs) in the control group and 25(OH)D3 group were 66.97% ± 8.29% and 52.18% ± 8.52%, respectively; the mean fluorescence intensities of MHC-II in the control group and 25(OH)D3 group were 1 102.16 ± 371.02 and 681.62 ± 292.71. The expression levels of MHC- II and CD86 on the surface of the DCs in 25(OH)D3 group were significantly lower than those of the control group. The ability of the DCs to stimulate proliferation of T-lymphocytes was also significantly lower than that of the control group.

CONCLUSIONS

These findings suggest that 25(OH)D3 modulates the immune response by affecting the maturation and function of DCs in Mycobacterium tuberculosis period.

Microbiome and Asthma: What Have Experimental Models Already Taught Us?

Asthma is a chronic inflammatory disease that imposes a substantial burden on patients, their families, and the community. Although many aspects of the pathogenesis of classical allergic asthma are well known by the scientific community, other points are not yet understood. Experimental asthma models, particularly murine models, have been used for over 100 years in order to better understand the immunopathology of asthma. It has been shown that human microbiome is an important component in the development of the immune system. Furthermore, the occurrence of many inflammatory diseases is influenced by the presence of microbes. Again, experimental models of asthma have helped researchers to understand the relationship between the microbiome and respiratory inflammation. In this review, we discuss the evolution of murine models of asthma and approach the major studies involving the microbiome and asthma.