Panel A: Box-and-whisker plots showing the horizontal axis represents the regions (C D R 1, C D R 2, F W R 1, F W R 2, F W R 3), and the vertical axis represents the mean S H M frequency in mutations per base pair. Each box plot includes data for immunoglobulin D (I g D), immunoglobulin M (I g M), immunoglobulin G (I g G), and immunoglobulin A (I g A). The top bar segment shows replacement mutation frequency, and the bottom bar segment shows silent mutation frequency. Error bars indicate standard error of the mean (s e m). Panel B: Box-and-whisker plots showing the horizontal axis represents the regions, and the vertical axis represents the mean R S ratio. Numbers below bars indicate median values for four data points. Panel C: Box-and-whisker plots showing the horizontal axis represents the gene usage, and the vertical axis represents the percentage usage. Numbers below bars indicate median values for four data points.
Tonsillar IgD-ME B cells are more mutated than other ME B cells and, compared with these cells, show molecular traces of antigen-driven selection, and show nonsignificantly increased usage of some intrinsically autoreactive IGHV genes. (A) Mean SHM frequency across CDRs and FWRs of IGHV genes from B cell and PC subsets of all donors (N = 4). Top bar segment, replacement mutation frequency; bottom bar segment, silent mutation frequency. Error bars, SEM. (B) Mean R:S mutation ratio across CDRs and FWRs of mutated antibodies from B cell or PC subsets (N = 4). Numbers below bars, median values for four data points. (C) Mean IGHV3-23, IGHV3-30, and IGHV4-34 gene usage by B cell and PC subsets (N = 4). Numbers below bars as in B. Data are from one experiment with multiple biological replicates (A–C). Significance was assessed with the Kruskal–Wallis test followed by a post hoc pairwise Mann–Whitney test with P value adjustment following the Benjamini–Hochberg method. *P < 0.05.