Variegated transfer of recombinant glycosylphosphatidylinositol-anchored CD4 among cultured cells: correlation of flow cytometric and microscopic observations.
Glycosylphosphatidylinositol-anchored proteins (GPI-proteins) expressed on the outer leaflet of cell membranes are involved in diverse physiologic as well as pathologic processes in humans. Previously, we demonstrated the intercellular transfer of overexpressed CD4-GPI in vitro from transduced HeLa cells to their parental cell line. In this report we present further information on the transfer process and the nature of the transferred GPI-proteins. In mixed-cell populations, the transfer of CD4-GPI was detectable within minutes at levels proportional to the ratio of donor and recipient cells. The amount of CD4-GPI detected with flow cytometry on the surface of the recipient cells varied according to cell type. Microscopy of mixed cell populations revealed discrete CD4-GPI containing aggregates on the target cells, whereas colocalized transfer of cytoplasm was not detected. Separation of cocultivated cells by semipermeable membranes largely prevented CD4-GPI transfer, but aggregates containing CD4-GPI were demonstrated by electron microscopy in supernatants passed through filters of 0.4-mm pore size.
Miller
J L
JL
Laboratory of Chemical Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Giattina
M
M
Mackie
E J
EJ
Dwyer
N K
NK
D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D002452:Cell Count; D002460:Cell Line / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D005434:Flow Cytometry / Q000379:methods; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence / Q000379:methods; D011994:Recombinant Proteins / Q000378:metabolism
D015704:CD4 Antigens; D017261:Glycosylphosphatidylinositols; D011994:Recombinant Proteins