Forced expression of A1 restores the ability of OX40 KO CD8 T cells to accumulate and survive over time in vivo.
Naive CD8 T cells from WT or OX40 KO OT-I TCR transgenic mice were stimulated with APCs/peptide. On day 2/3, T cells were transduced with retroviral vectors expressing GFP, or GFP with A1. On day 5 of primary culture, GFP+ CD8 T cells were sorted and adoptively transferred into naive C57BL/6 recipient mice that were subsequently challenged i.p. with whole OVA protein in PBS (filled bars) or PBS alone (open bars). (a) On days 5, 10, and 15, GFP+Vβ5+CD8+ T cells were enumerated from pooled lymph nodes and spleen. Data are mean number of GFP+Vβ5+CD8+ cells ± s.d from four individual mice and representative of three experiments (* P<0.05, ** P<0.01, Student's unpaired t-test). (b) At day 15, percentage of GFP+CD44+ T cells was analyzed by flow cytometry, after gating on live CD8+ T cells in the spleen. Results are representative of three experiments.