Des-TCR CD8 T cells in K^b-tolerant and K^b-reactive mice do not differ in homeostatic expansion and CD44 expression. (A) The absolute number of CD8 T cells in spleens of adult nonthymectomized (non-Tx) and thymectomized (Tx) Des-TCR × 2.4KerIV-K^b.RAG2^−/− (tolerant) and Des-TCR.RAG2^−/− (reactive) mice were determined (at the age of 9 weeks; n = 5-9 mice/group; P < .01 for the respective nonthymectomized versus thymectomized mice). (B) Three-week-old thymectomized Des-TCR × 2.4KerIV-K^b.RAG2^−/− (tolerant) and thymectomized Des-TCR.RAG2^−/− (reactive) mice were given BrdU (0.8 mg/mL) into the drinking water for 10 days. Six weeks later, spleen and lymph node CD8 T cells were analyzed by flow cytometry for incorporation of BrdU. Shown are mean percentages ± SD of BrdU-positive CD8 T cells (n = 4). (C) Splenocytes from thymectomized (Tx) and from nonthymectomized (non-Tx) Des-TCR × 2.4KerIV-K^b.RAG2^−/− (tolerant; percentage of CD44^high CD8 T cells: 47.3% ± 13.8% versus 32.4% ± 3.6%, P < .05) and Des-TCR.RAG2^−/− mice (reactive; percentage of CD44^high CD8 T cells: 44.6% ± 12.9% versus 30.0% ± 4.2% P < .05) were analyzed by flow cytometry for CD44 expression after gating on Des-TCR CD8 T cells. Shown are relative log fluorescence intensities for CD8 and CD44. The numbers represent the mean percentages of CD44^high CD8 T cells and were pooled from 4 independent experiments.