Fusion efficiency enhancement. The fusions were performed according to a standard protocol, where the culture media and PEG were reconstituted from powder forms with either NPD or DI water. For each fusion, PBMC from a single batch were divided into two equal fractures and used to prepare two parallel experiments, in NPD or DI based reagents. The figure presents percent of hybridoma-positive wells in each fusion experiment. The percent was calculated as the number of hybridoma-positive wells from 96-well plates where the cells were seeded and grown after the fusion process. The difference between the NPD- and DI-fusion results was found to be statistically significant by Chi-square analysis (p << 0.05) for all experiments. The percent of enhancement was calculated by the formula [(number of hybridomas in NPD-fusion/number of hybridomas in DI-fusion) x100-100%].