(A) 6.5 expression and frequencies of thymocytes and 6.5+CD4SP thymocytes from 4 and >12 wk-old TS1 (light lines, open bars), TS1×HA104 (dashed lines, grey bars) and TS1×HACII (dark lines, closed bars) mice. (B) 6.5 expression and frequencies of splenocytes and 6.5+CD4+ splenocytes from 4 and >12 wk-old TS1 mice. TS1 (light lines, open bars), TS1×HA104 (dashed lines, grey bars), and TS1×HACII (dark lines, closed bars). (C) Histograms show 6.5 expression on CD4+ splenocytes from TS1 (grey line) and TS1.RAG−/− (black line) mice (upper panel), and from TS1×HACII (grey line), TS1×HACII.RAG−/− (black line), and TS1.RAG−/− (dashed line) mice (lower panel).