Characterization of the helper memory T cells and NK cells expressing sialyl 6-sulfo Le^x by 4-color analyses. Representative results obtained from analysis of 12 persons. (A) Two-dimensional distribution of sialyl 6-sulfo Le^x (G152), variant sialyl Le^x (2F3) and CLA (HECA-452) with PSGL-1 (PL1), L-selectin (Leu 8), CCR4 (KM2160), α₄β₇ integrin (FIB504), CCR7 (150 503), or CCR9 (112 509) on the gated CD4⁺CD45RO⁺ helper memory T-cell population. (B) Two-dimensional distribution of sialyl 6-sulfo Le^x with PSGL-1 or L-selectin on the gated CD56⁺CD3^– NK-cell population.