title: An acid phosphatase assay for quantifying the growth of adherent and nonadherent cells.
abstract: We describe an acid phosphatase assay for determination of cell growth based on quantification of cytosolic acid phosphatase activity. The assay is based on the hydrolysis of the p-nitrophenyl phosphate by intracellular acid phosphatases in viable cells to produce p-nitrophenol. For all cell types examined, absorbance of p-nitrophenol at 405 nm is directly proportional to the cell number in the range of 10(3)-10(5) cells. The assay can quantify as few as 1000 cells per well in 96-well microtiter plates. The acid phosphatase assay was used to count various adherent and nonadherent cells, including human tumors, L6, and HT-2 cells. We also demonstrate the utility of this assay for analysis of growth factor and cytokine bioactivity on mammalian cells in culture. In comparison to [3H]thymidine incorporation, the acid phosphatase assay has similar sensitivity but a wider linear response range. The method also shows higher sensitivity and reproducibility in comparison to cell proliferation assays based on the reduction of tetrazolium salts. Because of the ease of use, sensitivity, and low cost, the acid phosphatase method is especially suited to applications where a large number of samples are assayed.
authors.affiliation: Cell Biology Group, CLONTECH Laboratories, Inc., Palo Alto, California 94303, USA.
authors.forename: T T
authors.initials: TT
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Sinai
authors.forename: S R
authors.initials: SR
authors.lastname: Kain
mesh_terms: D000135:Acid Phosphatase; D001681:Biological Assay; D002448:Cell Adhesion; D002455:Cell Division; D002460:Cell Line; D006801:Humans; D012680:Sensitivity and Specificity
chemical_list: D000135:Acid Phosphatase