Transfected leukocyte integrin CD11b/CD18 (Mac-1) mediates phorbol
ester-activated, homotypic cell:cell adherence in the K562 cell line
DD Hickstein, E Grunvald, G Shumaker, DM Baker, AL Back, LJ Embree, E Yee and KA Gollahon
Medical Research Service, Seattle Veterans Affairs Medical Center, WA
98108.
The CD11b/CD18 leukocyte integrin molecule mediates diverse neutrophil
adherence-related functions, including cell:cell and cell:extracellular
matrix attachments. To study the individual role of this leukocyte integrin
in cell adherence in hematopoietic cells, we expressed the CD11b/CD18
complex on the surface of K562 cells, a cell line derived from an
individual with chronic myelogenous leukemia in blast crisis. We used an
amphotrophic retroviral vector designated LCD18SN, harboring the complete
coding sequence for the CD18 subunit, to transfer the CD18 cDNA into K562
cells and select stable cell lines. The CD11b subunit in the expression
plasmid pREP4 was transfected into these K562/CD18 cells by electroporation
and stable cell clones were selected. These K562 cells possessed RNA and
intracellular protein for each subunit, and they expressed the CD11b/CD18
heterodimer on the cell surface. When CD11b/CD18 expressing K562 cells were
stimulated with phorbol myristate acetate (50 ng/mL) for 24 to 48 hours,
these K562 cells formed dense cell:cell aggregates. This homotypic
aggregation required both activation of the CD11b/CD18 complex and the
induction of the counter- receptor for CD11b/CD18 on the conjugate cell.
This cell line will (1) enable the structure-function relationships between
cell activation and homotypic adherence to be assessed, (2) provide the
opportunity to identify accessory molecules required for activation of the
CD11b/CD18 complex, and (3) facilitate the identification of novel ligands
for the CD11b/CD18 complex.
Volume 82,
Issue 8,
pp. 2537-2545,
10/15/1993
Copyright © 1993 by The American Society of Hematology
