Table I

HSC engraftment capacity as a function of cell cycle status

3–4 wk9–12 wk>18 wk
PhaseCell #Frequencyreconstitution(#/total)Average chimerism(range)engraftment type(#/reconstituted)Frequencyreconstitution(#/total)Average chimerism(range)engraftment type(#/reconstituted)Frequencyreconstitution(#/total)Average chimerism(range)engraftment type(#/reconstituted)
LT-HSC
G01057% (8/14)1.1% (0.1–3.9%)
 M + L (8/8)57% (8/14)4.7% (0.3–15.2%)
 M + L (8/8)54% (7/13)7.5% (0.6–23.7%)
 M + L (7/7)
50100% (5/5)1.5% (0.1–5.8%)
 M + L (5/5)100% (5/5)5.7% (0.5–14.3%)
 M + L (5/5)100% (5/5)11.8% (0.3–35.3%)
 M + L (4/5), L only (1/5)
G1108% (1/12)0.2%
 M only (1/1)0% (0/11)n/a0% (0/11)n/a
5050% (3/6)4.2% (0.1–12.5%)
 M only (3/3)0% (0/5)n/a0% (0/5)n/a
S-G2/M100% (0/9)n/a0% (0/9)n/a0% (0/9)n/a
5050% (3/6)0.4% (0.2–0.7%)
 M + L (3/3)33% (2/6)0.35% (0.3–0.4%)
 M + L (1/2), L only (1/2)33% (2/6)0.15% (0.1–0.2%)
 L only (2/2)
KTLS HSC
G01050% (6/12)0.7% (0.1–1.2%)
 M + L (5/6), M only (1/6)42% (5/12)3% (0.2–10.6%)
 M + L (5/5)42% (5/12)3.2% (0.3–8.3%)
 M + L (4/5), L only (1/5)
50100% (4/4)0.7% (0.1–1.2%)
 M + L (4/4)100% (4/4)2.9% (0.4–8.2%)
 M + L (4/4)100% (4/4)3.0% (0.2–6.2%)
 M + L (4/4)
G1100% (0/10)n/a0% (0/10)n/a0% (0/10)n/a
5025% (1/4)0.3%
 M (1/1)0% (0/4)n/a0% (0/4)n/a
S-G2/M100% (0/10)n/a0% (0/10)n/a0% (0/10)n/a
5020% (1/5)0.6%
 M + L (1/1)20% (1/5)0.3%
 L only (1/1)0% (0/5)n/a
  • LT-HSC and KTLS HSC were first double sorted from C57BL/6-Ly5.1 donor mice, stained with H/PY, resorted for cell cycle G0 (H2N/PY), G1 (H2N/PY+), and S-G2/M (H>2N-4N/PY+) subpopulations and tested for their engraftment capacities by competitive reconstitution assays. 10 or 50 cells were transplanted into lethally irradiated congenic C57BL/6-Ly5.2 recipient mice, together with 3 × 105 Ly5.2+ helper BM cells. Recipient mice were considered to be reconstituted by Ly5.1+ donor cells if the frequencies of Ly5.1+ donor-derived myeloid (M, Gr-1+, or Mac-1+) or lymphoid (L, B220+, or CD3+) cells detected in the peripheral blood at the indicated times after transplantation were greater than background levels (0.1% as determined by parallel analysis of untransplanted control C57BL/6-Ly5.2 mice). M+L indicates multilineage reconstitution. n/a, not applicable.