HA stimulates myelopoiesis in LTBMC. (A) Nonadherent cells from myeloid LTBMC in the absence of HA (control) or treated with HA (100 μg/mL; rooster comb HA from Sigma) were determined each week. SE was calculated from results obtained from 3 independent wells. The inset shows the dose-dependent effect of HA on the production of nonadherent cells in myeloid LTBMC after 4 weeks in culture. The asterisk indicates the use of heat-treated HA (1 hour at 95°C). The bars indicate the SE determined from results obtained from 3 independent wells. (B) Clonogenic cells in myeloid LTBMC grown in the absence of HA (control) or presence of HA (100 μg/mL) were determined at the time indicated by plating of nonadherent cells in semisolid methylcellulose culture medium in the presence of IL-3 (Materials and Methods). SE was calculated from results obtained from 3 different wells.