Four subsets of B cells are distinguished from one another in their Ig CDR3 properties. The amino acid sequence of the Ig CDR3 region was determined from V-Quest for each sequence and subjected to ProtParam²⁵  analysis to determine the peptide characteristics for transitional (T, n = 433), naive (N, n = 662), switched memory (S, n = 1293), and IgM memory (M, n = 1209) populations. Error bars are SEM. *P < .05; **P < .005; ***P < .0005.