Fig. 3.

P14 cells that are recruited into the response proliferate to the same extent in the presence or absence of competition. (A) CFSE-labeled P14.Thy1.1 cells were transferred into mice with or without OT-I cells, and mice were immunized with 2 × 10⁶ peptide-pulsed DCs. Spleen cells were tested for proliferation at 48 h. The proliferation platform function of FlowJo was used to determine the number of P14 cells that divided at least once and the average number of divisions for those cells. Multiple experiments were combined for a total of nine mice per group. (B) Cell transfer and immunization was performed as in A, and spleen cells were analyzed at 18, 44, and 96 h as shown. Four hours before death, mice were injected i.p. with 1 mg of BrdU in 100 μl of PBS. Cells were analyzed as in other figures except intracellular staining for BrdU incorporation was performed. MFI for BrdU staining is shown for undivided P14 cells and at rounds 1–4 of cell division for the 44-h time point. ■, P14 alone; ●, P14 + OT-I.