V and J gene usage frequencies of out-of-frame and in-frame TCR clonotypes. Frequencies include TCRα (A) and TCRβ (B) V gene or TCRα (C) and TCRβ (D) J gene usage of unique TCR clonotypes in CD4 T cells of ABabDII mice (n = 5), ABabDR4 (n = 5) mice and human donors (n = 3). The gene segments were arranged on the x axis according to their position on the human chromosome from 5′ to 3′. TRAV18 usage was not detected, most likely because of PCR bias, and was excluded from the graph. Dashed line indicates frequency for random V gene usage (TRAV, 2.3%; TRBV, 2.1%). All data are shown as means ± SD. *, V genes whose expression is missing in ABab transgenic mice.