Seeding efficiency, plating efficiency, and population doublings of human skin fibroblastlike cells: Results of replicate testing

Using skin fibroblastlike cells from 10 healthy volunteers, 12 to 54 yr old, we measured, in replicates, seeding efficiency (SE), plating efficiency (PE), and population doublings (PD) during 2 wk of growth and the cumulative replicative life span (CRLS). We determined the effects of donor age and of in vitro cell age on the test results and test precision. We found that (a) On the average, SE was 82%±24 SD, PE was 12%±9 SD, PD was 7.3 doublings ±2.5 SD, and CRLS was 31.1 doublings ±9.6 SD. (b) Plating efficiency and PD correlated well with each other and with CRLS whereas SE did not correlate with PE, PD, or CRLS. (c) Plating efficiency and PD were affected negatively by increasing passage levels and by donor ages, but the influence of age was evident only for cells from early passages. Seeding efficiency was not affected by either of the two variables. (d) Variations in PD from early passages explained half of the donor-to-donor variation in CRLS whereas PD from later passages had little or no predictive power. (e) Of the two short term tests, PD had better precision than PE. For replicate runs with cells from early passages the coefficient of variation was 44% for PE and 15% for PD. The results show that PD for cells from early passages in mass culture give rapid results, which express the in vitro replicating potential of cells from different donors with greater precision than do measurements of CRLS.