Clonally related B cells detected in both memory and plasmablast populations. (A) Alignment of CDR3 protein sequences as well as V_H-D-J_H and V_κ-J_κ gene segment use of clonally related memory B cells and plasmablasts. Amino acid differences are shaded in gray. (B) Variable gene segments were aligned at the nucleotide level for clonally related memory B cells and plasmablasts. Solid vertical lines represent coding/replacement mutations, and dashed lines silent mutations per codon, compared with the most homologous germline segment. Asterisks denote coding mutations that occurred at the same codon positions but resulted in different amino acids between the aligned sequences.