Evaluation of Peripheral Blood Mononuclear Cell Processing and Analysis for Survival Motor Neuron Protein
Figure 2
Study 2: Impact of post-isolation delay and cell freezing.
SMN signals were evaluated in PBMCs from 4 individuals that were analyzed with 45 minute, 2 h and 24 h delays after cell isolation. A subsample from each timepoint was frozen to assess post-freezing viability and SMN signals. A: Cell viability was generally lower in PBMCs that had been frozen, ranging from 88–95% viability compared to 93–98% in unfrozen cells. Statistical comparisons were made to the 0 h timepoint. B: The comparative recovery of viable PBMCs after freezing relative to fresh samples was only ∼40–60% at all timepoints, suggesting a major loss of cells in the freezing process. C: Delaying the processing of isolated PBMCs to lysates had no impact on protein concentrations through delays of 2 h, however there was again a trend for increased protein concentrations in samples left for 24 h. D: SMN levels (normalized to protein concentrations) in unfrozen PBMCs were generally similar across all timepoints, despite wide variability in signals. E: Analysis of SMN by cell counts revealed that SMN signals in unfrozen cells tended to increase with post-isolation delays. Frozen cell SMN signals generally seemed to decrease over time compared to both frozen cells processed with minimal delays or compared to unfrozen cells. Signals from frozen cells with 24 h post-isolation delays were lower than unfrozen cells. Error bars represent minimum and maximum values. In Figure 2 the bodies of the boxplots indicate the first and third quartiles, while the horizontal bar indicates the median.