Figure 4. Csk inhibition potentiates response to weak agonists.
(A) CskAS;OTI naive CD8+ T cells were stimulated with MitoC-treated WT splenocytes, preloaded with indicated peptides, in presence of DMSO or 5 μM 3-IB-PP1 for 4 hr and CD69 upregulation was measured by flow cytometry. (B) CskAS;OTI naive CD8+ T cells were stimulated as in A with varying doses of 3-IB-PP1 with dose–response fit. (C) EC50 of 3-IB-PP1 (nM) for % CD69 positive cells for data in B. Data are representative of two independent experiments.
Figure 4—figure supplement 1. TCR Valpha2 downregulation in cells in Figure 4A.
Only OVA triggers peptide-dependent TCR downregulation. 5 μM 3-IB-PP1 induces ligand-independent downregulation of TCR, as seen in VSV peptide. In the presence of CskAS inhibition, all the other altered peptides induce further, dose-dependent loss of TCR.