CD8A and neoplasm: To assess further how GPX4 ablation affected α4-1BB–mediated tumor antigen–specific CD8+ T cell responses in vivo, preactivated OT-1 WT (CD45.1+) and GPX4–/– (CD45.2+) CD8+ T cells congenic for CD90.2 were mixed at a 1:1 ratio and cotransferred into LLC1-Ova tumor–bearing recipients (CD90.1+) followed with or without α4-1BB treatment.