Pneumococcal Δ<i>pep27</i>Immunization Attenuates TLRs and NLRP3 Expression and Relieves Murine Ovalbumin-Induced Allergic Rhinitis
Jae Ik Yu, Ji-Hoon Kim, Ki-El Nam, Wonsik Lee, Dong-Kwon Rhee
Abstract
Allergic rhinitis (AR), one of the most common inflammatory diseases, is caused by immunoglobulin E (IgE)-mediated reactions against inhaled allergens. AR involves mucosal inflammation driven by type 2 helper T (Th2) cells. Previously, it was shown that the Streptococcus pneumoniae pep27 mutant (pep27) could prevent and treat allergic asthma by reducing Th2 responses. However, the underlying mechanism of pep27 immunization in AR remains undetermined. Here, we investigated the role of pep27 immunization in the development and progression of AR and elucidated potential mechanisms. In an ovalbumin (OVA)-induced AR mice model, pep27 alleviated allergic symptoms (frequency of sneezing and rubbing) and reduced TLR2 and TLR4 expression, Th2 cytokines, and eosinophil infiltration in the nasal mucosa. Mechanistically, pep27 reduced the activation of the NLRP3 inflammasome in the nasal mucosa by down-regulating the Toll-like receptor signaling pathway. In conclusion, pep27 seems to alleviate TLR signaling and NLRP3 inflammasome activation to subsequently prevent AR.