DIFFERENTIAL MEMBRANE LABELING OF HUMAN LYMPHOCYTE SUBSETS BY PKH-2 EXAMINED BY MULTIPARAMETER FLOW-CYTOMETRY - A POSSIBLE CORRELATION BETWEEN LIPID-COMPOSITION OF CELLULAR MEMBRANES AND FUNCTIONAL-PROPERTIES

Human peripheral blood lymphocytes were stained simultaneously with the lipophilic membrane label PKH-2 and surface markers and analysed by multiparameter flow cytometry. A biphasic staining distribution was observed for T (CD3+) as well as B (CD19+) cells. Within the T subset, CD4+ cells stained almost exclusively with bright PKH-2 intensity, while CD8+ cells exhibited a more pronounced bimodal staining pattern. No difference in staining intensity was noted for CD4+CD45R0+ vs. CD4+CD45R0- cells. This multiparameter staining method demonstrates differences in membrane lipid composition between different human lymphocyte subsets, and suggests that caution must be exercised when evaluating PKH-2 labelling of human lymphocytes.