Application of Lactobacillus paracasei HB89 mitigates aluminum hydroxide combined with OVA allergen in an allergic animal model

Allergic airway inflammation, primarily driven by a Th2-biased immune imbalance, remains a significant global health concern. This study investigated the immunomodulatory potential of Lactobacillus paracasei HB89 in a murine model of ovalbumin (OVA)-induced allergic asthma. Female BALB/c mice were sensitized and challenged with OVA to establish an allergic airway hyperresponsiveness (AHR) model, while L. paracasei HB89 was administered via oral gavage daily for ten consecutive weeks. Results demonstrated that HB89 intervention was well-tolerated and significantly enhanced innate immune surveillance, evidenced by increased natural killer (NK) cell cytotoxicity and phagocytic activity. While maintaining splenic lymphocyte homeostasis, HB89 markedly attenuated Th2-driven systemic responses, as shown by a significant reduction in total serum IgE. Furthermore, HB89 treatment effectively modulated the inflammatory microenvironment by downregulating IL-4 and IL-5 secretion in both stimulated splenocytes and bronchoalveolar lavage fluid (BALF). Crucially, HB89 administration significantly mitigated AHR, markedly reducing methacholine-induced airway resistance. Collectively, these findings suggest that L. paracasei HB89 alleviates allergic airway inflammation by rebalancing Th1/Th2 cytokine profiles and strengthening innate immunity, positioning it as a promising functional probiotic for managing allergic airway diseases.