Effects of anti-gp130 MoAbs (A) and TPO-neutralizing Ab (B) on the Mk clonal growth from CD34⁺ cells supported by a complex of IL-6/sIL-6R in serum-free methylcellulose culture in the presence of SCF. 500 CD34⁺ cells purified from cord blood were initiated and various concentrations of Abs were added at the beginning of the culture. Mk colonies including CFU-Mk, BFU-Mk, MK-Mix were scored at day 11. The number of Mk colonies indicates mean ± SD from triplicate cultures.