Ligand-dependent downregulation of MR1 cell surface expression by Salio, M, Awad, W, Veerapen, N, Gonzalez-Lopez, C, Kulicke, C, Waithe, D, Martens, AWJ, Lewinsohn, DM, Hobrath, JV, Cox, LR, Rossjohn, J, Besra, GS, Cerundolo, V