Residual homing of a a4ß7-expressing ß1+PI16+ regulatory T cell subset correlates with exposure-efficacy of vedolizumab

In vitro and in vivo data from our lab show that TReg cells exhibit a right-shifted vedolizumab binding profile compared with TEff cells. Consistently, in a certain concentration range, the residual adhesion, transmigration and homing of TReg cells was higher than that of TEff cells. To better understand why vedolizumab binding was different between TReg and TEff in a certain concentration range, we performed single cell RNA sequencing of Memory CD4 T cells expressing a4 and ß7 integrin and compared cells binding to vedolizumab or not binding to vedolizumab (previously purified using FACS with fluorescently labelled vedolizumab). Overall design: Examination of previously sorted CD4+ CD45RO+ alpha4+ beta7+ cells binding or not binding to vedolizumab at a certain concentration