CRBN controls antigen-specific CD8⁺ T-cell activation. (A) OVA-reacting, tetramer-positive CD8⁺ splenocytes from OT1 and OT1;Crbn^−/− mice. (B-C) Total number of CD69-expressing OT1 and OT1;Crbn^−/− T cells at 72 hours in response to SIINFEKL (N4, B), or in response to N4, SAINFEKL (A2), SIIGFEKL (G4), or Trp2 peptides, with or without added IL-2 (C). (D) CD69 expression in OT1 and OT1;Crbn^−/− T cells after 24, 49, and 72 hours of culture with 0.1 nM N4 or A2 peptide. (E) Dose response of peptide-reactive T cells with 0.1 nM of N4, A2, or G4 peptide stimulation, as determined by cell counting. (F) Percentage of viable CD8⁺ T cells after stimulation with the N4, A2, and G4 peptides for 72 hours. Basal ECARs (G) and basal OCRs (H) from OT1 and OT1;Crbn^−/− CD8⁺ T cells stimulated with SIINFEKL peptide for 24 hours. (I) Percentage of cytotoxicity of OT1 and OT1;Crbn^−/− T cells vs OVA-expressing B16 cells (72-hour coculture). (J) Flow analysis of glucose uptake based on fluorescent glucose analogue, 2-NBDG;G-MFI, after 48 hours of activation with the N4, A2, and G4 peptides of OT1 and OT1;Crbn^−/− T cells in CD69⁺ cells. (K) Summary of data shown in panel J. All results are representative of at least 2 independent experiments. n.s., not significant, *P < .05; **P < .01; ***P < .001; ****P < .0001.