( A lymphocyte stimulation assay w...)Cell Proliferation Assays

A lymphocyte stimulation assay was performed in another experiment on TopCount. Mouse spleen cells were cultured to approximately 10⁶ cells/ml in a 96-well cell culture plate and stimulated with increasing amounts of anti-CD3. As in the first experiment, all wells were harvested simultaneously into a UniFilter plate using the MicroMate 196 Cell Harvester. After processing and counting on the TopCount, all individual filter disks were removed from the filter plate, solubilized, and counted in a conventional LSC.

The CPM results from the two instruments correlated well (R² = 0.994). The TopCount efficiency was 28%, despite the fact that the DNA was not solubilized off the filter. The LSC efficiency with solubilization of the DNA into the scintillation fluid was 45%. The dose-response curves from the assay for both TopCount and LSC are shown in Figure 2. The results are identical within experimental error.

Conclusions

Cell proliferation assays have been performed with the MicroMate 196 Cell Harvester and TopCount, using Packard UniFilter plates. The experiments show that results obtained on TopCount will be identical to those obtained on traditional liquid scintillation counters. Since the filter disks are optically and physically isolated, sample and cocktail migration, as well as optical crosstalk, are eliminated. The TopCount Microplate Scintillation Counter can reduce manual labor, increase throughput, and decrease costs of cell proliferation assays.