Age-related gain of stromal cell competence.

Stromal layers were prepared from the femur at different ages, then their capacity to support day 7 CAFC and day 35 LTC-IC/CAFC from normal marrow was compared using LDA. Single-cell suspensions of reporter cells were seeded in 24 replicates at each of the 4 dilutions. Log percentage of wells negative for CAFC are plotted against initial cell input and 1× values were intrapolated at the −37% value. (A) Day 7 CAFC. (B) Day 35 LTC-IC/CAFC. Symbols represent stromal cells prepared at different postnatal ages: day 5 (○), day 7 (■), day 8 (⋄), day 10 (●), 2 months (⧫). The MS-5 cell line (*) was used as a control reference.