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There is evidence that IL-22 and IL-17 participate in the pathogenesis of allergic asthma. To investigate the role of IL-22, we used IL-22 deficient mice (IL-22 KO) sensitized and challenged with ovalbumin (OVA) and compared with wild type (WT) animals exposed to OVA. IL-22 KO animals exposed to OVA showed a decreased number and frequency of eosinophils, IL-5 and IL-13 in the airways, reduced mucus production and pulmonary inflammation. In addition, IL-22 KO animals exhibited a decreased percentage and number of lung CD11c + CD11b + cells and increased apoptosis of eosinophils. Th17 cell transfer generated from IL-22 KO to animals previously sensitized and challenged with OVA caused a reduction in eosinophil frequency and number in the airways compared to animals transferred with Th17 cells generated from WT mice. Therefore, IL-22 is deleterious with concomitant secretion of IL-17. Our findings show a pro-inflammatory role for IL-22, confirmed in a model of allergen-free and allergen-specific immunotherapy. Moreover, during the comorbidity asthma and pneumonia that induces neutrophil inflammation, IL-22 was not detrimental. Our results show that targeting IL-22 would negatively affect the survival of eosinophils, reduce the expansion or migration of CD11c + CD11b + cells, and negatively regulate allergic asthma.

Ethnopharmacological Relevance: Propolis is a natural product produced by honeybees used as a medicine at least to 300 BC. In the last decades, several studies showed biological and pharmacological properties of propolis, witch scientifically explains the empirical use for centuries. The anti-inflammatory activity of propolis with the purpose to reduce Th2 inflammation has been evaluated in allergic asthma. However, it remains to be determined how propolis negatively regulates the immune response after allergen re-exposure., Aim of the Study: We hypothesized that the anti-inflammatory activity of propolis is dependent on the induction of myeloid derived suppressor cells (MDSC) and regulatory T cells., Materials and Methods: To assess this hypothesis, we used an ovalbumin-induced asthma model to evaluate the effect of EPP-AF® dry extract from Brazilian green propolis., Results: Propolis treatment decreased pulmonary inflammation and mucus production as well as eosinophils and IL-5 in the broncoalveolar lavage. Propolis enhanced also in vitro differentiation and in vivo frequency of lung MDSC and CD4 + Foxp3 + regulatory T cells., Conclusions: Together these results confirm the immunomodulatory potential of propolis during sensitization and challenge with allergen. In addition, the collecting findings show, for the first time, that propolis increases the frequency of MDSC and CD4 + Foxp3 + regulatory T cells in the lungs, and suggest that it could be use as target for development of new immunotherapy or adjuvant immunotherapy for asthma., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2019. Published by Elsevier B.V.)

Background and Objective: The prevalence of asthma has increased in communities that adopt a Western lifestyle and become more urbanized. Probiotics may be effective in the prevention of allergic diseases, such as asthma. The aim of the current study was to examine the effects of Saccharomyces cerevisiae UFMG A-905 in an allergic model of asthma., Methods: Balb/c mice were sensitized twice with ovalbumin (OVA) intraperitoneally, 1 week apart and challenged with OVA intranasally for 3 days. Mice were daily treated with S. cerevisiae UFMG A-905 via gavaging needle 10 days before OVA sensitization and during challenges. After challenge, in vivo lung function was measured, and bronchoalveolar lavage (BAL) and lung inflammation were assessed., Results: Oral treatment with S. cerevisiae UFMG A-905 significantly decreased airway hyperresponsiveness, total cell number and the influx of eosinophils to the airway, inflammatory cell in the lung, mucus expression in epithelial cells and the levels of IL-4, IL-5 and IL-13. Additionally, S. cerevisiae UFMG A-905 restored the levels of IL-10 and interferon (IFN)-gamma, and increased the levels of IL-17A., Conclusion: Oral administration of S. cerevisiae UFMG A-905 prevented the development of major asthma-like characteristics in a mouse model., (© 2017 Asian Pacific Society of Respirology.)