Ovalbumin antigen-specific activation of T cell receptor closely resembles antibody stimulation as revealed by BOOST phosphotyrosine proteomics

Here we provide a framework to qualtitatively evaluate the tyrosine phosphorylation-mediated signaling pathways triggered by antigen-independent antibody and antigen-specific OVA peptide-MHC using Jurkat T cells expressing OT-1 T cell receptors. Our data suggest that pTyr-mediated regulatory axis triggered by OVA antigen-specific activation of TCR closely resembled that of antigen-independent stimulation using anti-TCR antibody, albeit OVA could likely induce a relatively stronger signaling effect. While data from this study do not invalidate previous studies of T cell signaling using antibody-based stimulation, our data revealed potential advantages of using peptide-MHC tetramers in studying T cell signaling. Antigen-specific activation of the OT-1 TCR using a panel of peptide-MHC tetramers (OVA, T4 and G4) generated data that correlates well with the corresponding binding affinity of the peptide-MHC, consistent with predicted signaling strength. Importantly, the apparent correlation between signaling strength and peptide-MHC affinity enables us to fine-tune the signaling strength of T cell stimulation in future studies, allowing a more precise control of the experimental parameter instead of a more binary antibody-based activation. Overall, we demonstrate the utility of BOOST to reveal new biological insights in the immune system.