Abstract:Allergic asthma is a prevalent chronic inflammatory disease characterized by airway hyperresponsiveness and airway inflammation, often triggered by inhalant allergens such as pet dander and pollen.Objective Studies have revealed that helper T cells (Th cells) play a crucial role in the immune regulation of allergic asthma. Particularly, Th2 cells exacerbate airway inflammation by secreting cytokines such as interleukin (IL)-4 and IL-5, which promote the proliferation of eosinophils and mast cells. Additionally, the activation of Th17 cells is closely related to the inflammatory response in allergic asthma. Therefore, modulating the balance of Th1/Th2 and Th17/Treg cells has become an effective strategy for treating allergic asthma. This study explores the pathogenesis of allergic asthma and novel therapeutic approaches.Methods We constructed an engineered bacterium EcNcanf-1 specifically expressing the dog allergen Canf-1. Using the pBAD promoter, we controlled the expression of Canf-1 in the lungs of mice.Results EcNcanf-1 exerted immunomodulatory effects by regulating pulmonary cytokine expression profiles, specifically downregulating the expression of pro-inflammatory cytokines including IL-6, IL-5, and IL-13, while upregulating the expression of anti-inflammatory mediators such as interferon-γ (IFN-γ), transforming growth factor-β (TGF-β), and IL-10, thus alleviating allergic symptoms in the lungs. EcNcanf-1 demonstrated remarkable efficacy in suppressing the pathological overexpression of Th2 and Th17 lymphocyte subsets under allergic conditions, while enhancing the functions of Th1 and regulatory T cells. Furthermore, EcNcanf-1 significantly reduced pulmonary mast cell infiltration, attenuated vascular permeability, and mitigated allergen-induced hypothermia and airway constriction. These findings demonstrated that EcNcanf-1 played a pivotal role in immune homeostasis regulation and represented a promising therapeutic candidate for allergic pulmonary inflammation through its multifaceted modulation of immunological pathways.Conclusion EcNcanf-1 provides a new therapeutic avenue for allergic asthma by modulating the expression of immune cells and cytokines. This not only offers new insights into the immune mechanisms of allergic asthma but also provides a scientific basis for the development of new targeted biological treatment strategies.