Selection of U937 histiocytic lymphoma cells highly responsive to phorbol
ester-induced differentiation using monoclonal antibody to the eosinophil
cytotoxicity-enhancing factor
MI Elsas, AJ Dessein and PX Elsas
Centre d'Immunologie, INSERM-CNRS de Marseille-Luminy, France.
Monoclonal antibodies (MoAbs) to the eosinophil cytotoxicity-enhancing
factor (ECEF) were used to detect ECEF in U937 cells before and after
phorbol ester (PMA)-induced differentiation into ECEF-secreting
macrophages. Membrane-associated ECEF (mECEF), apparently an integral
membrane component, is found in U937 cells and in 70% of monocytes and, at
lower levels, on blood T lymphocytes. Expression of mECEF in U937 cells is
heterogeneous, as is responsiveness to PMA. In PMA-treated cultures, the
strongest mECEF expression is on adherent, differentiated macrophages,
rather than on activated, nonadherent cells. To study the relationship of
mECEF to PMA responsiveness, we positively selected by "panning" a cell
line (U937 P+) with significantly higher mECEF expression than that of
U937. U937 P+ cells respond to PMA as a differentiation stimulus more
effectively than do U937 cells, with a fourfold increase in the number of
differentiated macrophages (P less than .001) and a faster rate of
differentiation (a fourfold increase at t = 12 hours, P less than .001).
U937 P+ cells also show a 7.4-fold increase in response to suboptimal doses
of PMA (P less than .001). These findings suggest that mECEF expression
correlates with responsiveness to a differentiation stimulus in a
histiocytic lymphoma cell line that is widely used as a model of monocyte
maturation.
Volume 75,
Issue 12,
pp. 2427-2433,
06/15/1990
Copyright © 1990 by The American Society of Hematology
