[Research progress on nasal mucosal immunity and intranasal vaccines].

Mucosal immunity can effectively prevent pathogen invasion of the mucosa at the initial stage of infection and inhibit pathogen replication within the body at later stages of infection. Therefore, the development of mucosal vaccines is of great significance for the prevention and control of infectious diseases. Intranasal vaccines can induce cellular, humoral, and mucosal immunity in the nasal mucosa and nasal-associated lymphoid tissue, producing secretory IgA, which plays a crucial role in preventing respiratory infections. However, the dilution of antigens by nasal mucus, clearance of antigens by cilia, and the barrier function of nasal epithelial cells in the nasal cavity can reduce the bioavailability of antigens and limit the efficacy of intranasal vaccines. This article reviews the structure of the nasal mucosal immune system and its mediated immune response, as well as intranasal vaccines that have been launched or are currently in clinical research, and explores the challenges faced in intranasal vaccine research.