Influence of HA and HA’ase on myeloid LTBMC from CD44 knock-out mice. Myeloid LTBMC from CD44-deficient mice were untreated or treated with HA or HA’ase as described in the legends to Figs 1 and3. The number of nonadherent cells (A) and hematopoietic progenitors (B) were measured once per week. SE was calculated from results obtained from 3 independent wells.