Comparative analysis of molecular germinal center signatures between antigen-experienced cells obtained from vaccinated controls versus systemic lupus erythematosus (SLE). VH sequences of individual cells sorted as recombinant C-fragment of tetanus toxin (TT)-specific plasma cells (TT+ PCs) and TT-specific memory B cells (TT+ mBCs) were pooled from three healthy donors after tetanus booster  and plasma cells from one patient with SLE (SLE PCs) . TT+ PCs and TT+ mBCs serve as effector cells generated as a result of prototypic T cell-dependent responses. (a) Mutation frequency. Each dot represents the value for one individual cell. (b) Ratios of replacement (R) to silent (S) mutations within complementarity-determining regions (CDRs) 1 and 2 and framework regions (FRs), respectively. (c) Frequency of mutations located within the two motifs RGYW and WRCY (R = purine, Y = pyrimidine, and W = adenine/thymine). (d) CDR3 length of individual B cells related to the underlying total number of mutations per sequence. Sequences of each cell type were divided into three categories according to their VH region mutations (that is, 0 to 5 mutations, 6 to 10 mutations, and more than 10 mutations) and are plotted against their respective CDR3 lengths. Bar indicates median.