Cell surface expression of CD44 on input, HA-adherent and HA-nonadherent CD34⁺ cells. CD34⁺ cells were stained with FITC-conjugated anti-CD44 MoAb J173. Negative controls (grey lines) are cells labeled with FITC-conjugated IgG1. Flow cytometric analysis was performed as described in the Materials and Methods. Data are from a representative experiment. Four independent experiments gave similar results.