Progeny of TS1 T_EM are outcompeted by progeny of TS1 T_N. HA104 mice received 750cGy and 8 × 10⁶ RAG^−/− BM cells in combination with 3000 Thy1.1 TS1 T_N, 3000 Thy1.2 TS1 T_EM, or a mix of both. On days 14, 21, and 28 spleen and colon cells were isolated. Representative flow cytometry plots showing Thy1.1 and Thy1.2 expression on splenic CD4⁺TS1⁺ cells on day 14 are shown in (A). The numbers of TS1 cells in the spleen and colon are shown in (B). P < .05 comparing numbers of T_EM that are transferred alone to numbers of T_EM that are cotransferred with T_N in the spleen and colon for all time points analyzed except for the colon on day 28, for which P = .138. Days 14 and 21 are combined from 2 independent experiments; day 28 is from 1 experiment. There were 8 mice per group for days 14 and 21 and 3 mice per group for day 28.