2D TCR–pMHC–CD8 kinetics determines T‐cell responses in a self‐antigen‐specific TCR system

Two‐dimensional (2D) kinetic analysis directly measures molecular interactions at cell–cell junctions, thereby incorporating inherent cellular effects. By comparison, three‐dimensional (3D) analysis probes the intrinsic physical chemistry of interacting molecules isolated from the cell. To understand how T‐cell tumor reactivity relates to 2D and 3D binding parameters and to directly compare them, we performed kinetic analyses of a panel of human T‐cell receptors (TCRs) interacting with a melanoma self‐antigen peptide (gp100₂₀₉–₂₁₇) bound to peptide‐major histocompatibility complex in the absence and presence of co‐receptor CD8. We found that while 3D parameters are inadequate to predict T‐cell function, 2D parameters (that do not correlate with their 3D counterparts) show a far broader dynamic range and significantly improved correlation with T‐cell function. Thus, our data support the general notion that 2D parameters of TCR–peptide‐major histocompatibility complex–CD8 interactions determine T‐cell responsiveness and suggest a potential 2D‐based strategy to screen TCRs for tumor immunotherapy.