 The T-cell receptor, TCR, is a key component of the immune system which recognizes foreign molecules known as peptids bound to major histocompatty complexes, PMHC. Upon binding, the TCR triggers a cascade of events leading to the activation of T-cells. In this study, researchers developed two models to better understand the mechanism behind the TCR's ability to recognize different types of PMHCs. They found that the TCR forms stronger bonds with strong PMHCs than it does with weak PMHCs, and that these bonds are dependent on the structure of both the TCR and PMHC. Additionally, they were able to use the models to predict the strength of the TCR-PMHC bond based on the structure of the TCR and PMHC. This study provides insight into the mechanisms underlying the TCR's ability to recognize different types of PMHCs, and could lead to new treatments for diseases such as cancer. This article was offered by Heung Kyu Choi, Pei Wensung, Junhao Ji, and others.