( Results for an adherent cell...)Cell Proliferation Kit Outperforms the Competition in the Range of Cells,,,Typically Counted

Results for an adherent cell line are plotted in Figure 1. COS-1 cells were counted using a hemocytometer, then plated at the densities shown in the graph. Cells were allowed to attach over four hours, then quantitated according to the manufacturers instructions for each kit. The resulting graphs showed that the Quantos cell proliferation assay kit provides a linear relationship of cell number versus fluorescence units (r²= 0.980). However, the other assay demonstrated a less linear relationship (r²= 0.897).

Figure 2

Results for a suspension cell culture are plotted in Figure 2. BJAB cells were counted using a hemocytometer, then plated at the densities shown in the graph. Cells were then quantitated according to the manufacturers instructions for each kit. Once again, the graph indicated that using the Quantos cell proliferation assay kit elicits a better linear relationship of cell number versus fluorescence units (r²= 0.974), compared to the other assay (r²= 0.938).

In both the adherent and suspension cell lines, the other assay demonstrated a plateau over 50,000 cells. In fact, the manufacturers product information sheet states the following: The linear range of the assay under these conditions is from 50 to 50,000 cells per 200 l sample. Since the number of cells in each tissue culture is determined by extrapolation from a standard curve, this nonlinearity makes calculating the cell number above 50,000 cells difficult and inaccurate.

To determine whether the observed competitors plateau of 50,000 cells could cause errors in quantitating cell number in a typical cell sample, we plated CHO cells at 100% confluency in 96-well
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