Characterizing B cell subsets in the lung. (A and B) Flow cytometry was used to analyze lung CD5⁺ B cells (A) and to compare the quantitative counts (B) between spleen and lung (unpaired Student’s t test, n = 3 independent experiments using three mice in total). (C–E) Flow cytometry was used to identify B1a, B1b, and B2 B cell subsets in the spleen (C) and lung (D) and to compare the two organs (E). Unpaired Student’s t test; n = 5 independent experiments using five mice in total. Data is mean ± SD. SSC, side scatter. ***, P < 0.001.