Enrichment, using MACS, of the transfected population on cells carrying the transgene. Relative ratio evolution of eGFP-positive cells within a population of T2EC cotransfected with the eGFP expression plasmid and the transposase-supplier helper plasmid (molecular ratio: 5/1). Rows: different time points after transfection (on days), ↓ symbolizes the evolution of the culture as a function of time. Columns: Successive MACS: cell cultures were sorted once (MACSx1), twice (MACSx2), three times (MACSx3) or not sorted at all (no MACS), → symbolizes the evolution of one culture before and after a sorting. Histograms illustrate the cell number repartition according to the fluorescence intensity, from one single representative experiment. Values in bold correspond to the mean ± SD after experiment repetition (n = 4). For the same given time point, conditions not connected by the same letter (a, b, c, or d) are significantly different, p < 0.05 (Tukey-Kramer HSD test, n ≥ 3). Values in italics correspond to the relative ratio of eGFP-positive cells within a population of T2EC transfected with the eGFP expression plasmid only (no transposase) and sorted once, twice, three times or not sorted at all. Cell fluorescence was analyzed by flow cytometry (FACS). The positive fluorescence threshold is fixed in order to have 99% of the negative cells (i.e. cells transfected with the empty plasmid) below this threshold. A 1% value is, hence, considered as null.