The phenotypic and functional study of tissue B cells in respiratory system provided important information for diseases and development of vaccines

The field of tissue‐resident B cells has received increasing attention, yet the feature of tissue B cells in respiratory system is unclear. Here, we first show that non‐circulating B cells obtained from nasal, trachea and lung tissues are numerically and phenotypically distinct from their circulating counterparts. Analysis of single cell transcriptome sequence identified multiple differentially expressed genes between non‐circulating B cells and circulating B cells, which illustrated their heterogeneity. Furthermore, we found high expression of CXCR3 on non‐circulating B cells, and the chemokine CXCL11 was also up‐regulated in the respiratory tissues, suggesting that CXCR3‐CXCL11 axis might accelerate the local resident of non‐circulating B cells in respiratory tract. Interestingly, intranasal immunization with BCG in mice elicited a sustained humoral immune response via induction of IgA and IgG Abs, which revealed the role of B cells. Meanwhile, tissue‐resident B cells, IgA(+) and IgG(+) memory B cells (MBCs) in respiratory tissues, as well as plasma cells in bone marrow, were expanded and maintained, and these subsets probably developed into antibody‐producing cells to participate in the local humoral immunity. Our data illustrate the phenotype and function of tissue B cells in the upper and lower airways, provide references for the prospective development of vaccines.