title: DNA-Seq of Bifidobacterium breve
design: Allergic rhinitis (AR) is a widespread upper-airway disorder characterized by inflammation of the nasal passages. It is immunologically mediated via the hypersensitivity type I mechanism, which is primarily elicited by the immunoglobulin E (IgE)-linking allergen-induced imbalance of Th2/Th1 immune response. Due to limited efficacy of current medications, probiotics have received attention for their potential in preventing and ameliorating AR. In this study, a Lacticaseibacillus paracasei strain GOLDGUT-Lpc969 (Lpc969), isolated from feces of healthy adults, had been proved to be effective in preventing AR. The strain significantly attenuated the release of histamine and degranulation in LPS induced RBL-2H3 cells. While in the OVA-induced AR mice, L. paracasei GOLDGUT-Lpc969 also exhibited significant decrease on the disease indicators such as disease activity index (DAI score), serum IgE, and serum histamine. Treatment with L. paracasei GOLDGUT-Lpc969 led to significant suppression of Th2-related cytokines IL-4, IL-5, IL-6, IL-13 and TNF-alpha in the serum of mice. Furthermore, a comparison of the genomes of three previously reported AR-effective L. paracasei strains (including GOLDGUT-Lpc969) and one non-effective L. paracasei strain revealed that the gene K03671 may play a key role in alleviating AR symptoms. In conclusion, this study highlights the efficacy of L. paracasei GOLDGUT-Lpc969 in AR prevention through suppressing Th2 immune response and proposes the potential involvement of the functional gene K03671 in ameliorating AR symptoms. Therefore, L. paracasei GOLDGUT-Lpc969 shows promise as a probiotic for preventing AR.