Each FDL shows expression of individual proteins ranging from no/low expression in blue to high expression in red. Clusters can be assigned a phenotype on the basis of these FDLs. Shown here are 12 proteins which allow identification of differentiation status (CCR7, CD45RO), polarization (CCR5, CCR4, CD161), activation (PD-1, T-bet, Eomes, Granzyme B), Tregs (FoxP3, CD25) and CXCR5+ cells.