IGHV gene features from IgG⁺memory B-cell antibodies. IgG⁺ memory B cells were sorted from 3 spleens each of RG SKI mice and RG SKI IL6 mice. (A) Pie charts depict VH family usage in RG SKI and RG SKI IL-6 mice. (B) Bar graphs show frequencies of IGVH-CDR3 length with ≤9, 10 to 14, 15 to 19, and ≥20 amino acids (aa). (C) Pie charts showing proportion of IgH sequences with 0, 1, 2, 3, 4, 5, 6, and 7 somatic mutations; 0 and 7 represents the minimum and maximum number of total mutations. (D) The ratio of R/S mutations in IGHV-FWRs and CDRs were calculated in RG SKI (top) and RG SKI IL6 (bottom) as mutated nucleotides per total base pairs analyzed. Replacement (R; black bar) and silent (S; white bar). The R/S ratio for each region is indicated. DH, heavy chain diversity segment; JH, heavy chain joining segment; VH, heavy chain variable segment.