OBJECTIVETo explore the biological effect of Notch ligand Delta-1 (Notch L delta-1) on the sIL-6R during the differentiation of erythroid hematopoiesis.

METHODSMononuclear cells (MNCs) was isolated from the normal cord blood using Ficoll graduation solution. MNCs were enriched for CD34(+) CD38(-) cells by CD34 immunomagnetic beads and a FACS Vantage. CD34(+) CD38(-) cells was cultured for 7 days in the presence of SCF, Flt3L, TPO and IL-3 (4GFs). The cultured cells was detected for the expression of IL-6R and GPA. The subsequently enriched CD36(+) erythroid progenitors were sorted for cells with IL-6R(+) and IL-6R(-) using FACS Vantage. The CD36(+) GPA(-) IL-6R(-) cells were respectively cultured in the 4GFs, 4GFs + IL-6 or 4GFs + FP6 containing medium in the presence or absence of Notch L delta-1 for 14 days and CD36(+) GPA high red cells were counted.

RESULTSIL-6R cells accounted for 95% of CD36(+) GPA(+) cells. The CD36(+) GPA(-) cells was clearly divided into IL-6R(+) (46%) and IL-6R(-) (54%) subpopulations, the IL-6R(+) cell subpopulation formed only a few GM colonies (2.1 +/- 1.8) and a greater number of BFU-E colonies were generated from the IL-6R(-) subpopulation (58.2 +/- 18.1) (P < 0.05). The number of CD36(+) GPA high cell was (1.400 +/- 0.180) x 10(6) in the presence of FP6, lower than that [(2.460 +/- 0.190) x 10(6)] in the presence of FP6 + Notch L delta-1 (P < 0.05).

CONCLUSIONNotch L delta-1 enhances the sIL-6R-mediated effects of IL-6 on the generation of erythroid cells.