Figure 7.

Characterization of the CDR-H3 region in the B-1 cell IGHM repertoire. B-1 cells from 10 young and 10 old donors were single cell sorted and the IgM VH regions were amplified and sequenced. From each clonotype only one representative sequence was considered for analysis. (A) N-region addition analysis of B-1 cell IgM from young and old donors. The percentages of sequences with zero N-additions at both junctions, one or more N-additions at both junctions, zero N-additions at V-D and one or more at D-J junctions, or zero N-additions at D-J and one or more at V-D junctions are shown. (B) Length distribution of complementarity determining region 3 (CDR-H3) is shown for B-1 cell IgM antibodies from young and old donors. Inset shows the distribution of individual CDR-H3 length from young and old donors (C) The distribution of somatic mutations for B-1 cell IgM antibodies from young and old donors is shown as percent of sequences with zero or more than one nucleotide mutation. Inset shows the distribution of mutations for each sequence from young and old donors. n.s. p > 0.05 by Mann–Whitney U-test.