CDR3 region analysis. CDR3 length distribution of TCRα (A) and TCRβ (B) clonotypes. For the in-frame clonotypes, the frequencies of different CDR3 lengths for ABabDII mice, ABabDR4 mice, humans, and C57BL/6 mice (only TCRβ) are shown in bar diagrams. For the out-of-frame clonotypes, only the mean frequency and SD for each CDR3 length are shown for each group at the corresponding length. Gaussian distributions were assumed and are shown as lines for all groups, including the C57BL/6 CDR3β (purple, dotted lines; R2 ≥ 0.99 for all samples). (C) Comparison of means of CDR3β lengths among ABabDII, ABabDR4, and C57BL/6 mice and humans. (D) Frequency of TCRs with the same number of CDR3 nucleotide insertions for TCRβ chains; insertions in C57BL/6 mice were included (purple dotted lines). (E) Frequency of TCRs with the same number of CDR3 nucleotide deletion of TCRβ chains from ABabDII mice, ABabDR4 mice, humans, and C57BL/6 mice. (D and E, left) Out-of-frame clonotypes from TCRα (top)/β (bottom). (D and E, right) In-frame. For all panels, **, 0.001 ≤ P < 0.05; n.s., not significant (Mann–Whitney test, two-tailed). Data are shown as means ± SD. Data are from ABabDII (n = 5), ABabDR4 (n = 5), and C57BL/6 (n = 3) mice and humans (n = 3).
