Acid phosphatase activity in mononuclear phagocytes and the U937 cell line:
monocyte-derived macrophages express tartrate-resistant acid phosphatase
RG Snipes, KW Lam, RC Dodd, TK Gray and MS Cohen
Tartrate-resistant acid phosphatase (TRAcP) is used as a marker for
osteoclasts, which are believed to be derived from phagocytic cells or
phagocyte stem cell precursors. To further investigate the relationship
between monocytic phagocytes and osteoclasts, acid phosphatase (AcP)
activity was measured by three different techniques in human peripheral
blood monocytes, monocyte-derived macrophages, and the U937 cell line. We
found that cytochemistry and gel electrophoresis led to similar results,
but that the colorimetric assay was inconsistent. Normal human peripheral
monocytes expressed both tartrate-sensitive and -resistant AcP. In culture
these cells formed polykaryons and expressed TRAcP activity that was
further identified as an isoenzyme associated with bone tissue. In
contrast, the U937 cells did not express TRAcP activity as measured by gel
electrophoresis. Both U937 cells and monocytes possess material that
interferes with interpretation of the colorimetric assay of AcP. The
presence of TRAcP in monocyte-derived macrophages further supports the
relationship between phagocytic cells and bone osteoclasts.
Volume 67,
Issue 3,
pp. 729-734,
03/01/1986
Copyright © 1986 by The American Society of Hematology
