Characterization of NK cells derived from Lin⁻ SP cells.

Lin⁻ SP cells were isolated and re-sorted on the basis of their expression CD7 or CD34 (B). The Lin⁻ SP resolved 2 distinct subpopulations when compared with Lin⁻ UCB (A). The reanalysis of sorted CD7⁺ and CD34⁺ SP cells (C,D, respectively) consistently demonstrated the purity of the fractions. The CD7⁺CD34⁻Lin⁻ SP cells and CD34⁺Lin⁻ SP cells were then grown in the different stroma-based cultures described in Table 1. The immunophenotype of the progeny of CD7⁺CD34⁻Lin⁻ SP cells (E, G, I) and CD34⁺Lin⁻ SP cells (F, H, J) grown under culture condition D (Table 1) are shown. For each culture, one quarter of the human CD45⁺ progeny were used to confirm the presence and maturity of CD56⁺ cells by their immunophenotype. Quadrant statistics are provided for the individual experiments depicted. These data are representative of 4 cultures derived from CD7⁺Lin⁻ SP cells and 2 cultures of CD34⁺Lin⁻ SP cells. An additional 2 cultures of CD34⁺Lin⁻ SP expanded but did not yield CD56⁺ cells after 8 weeks in culture.