Fig. 4.

Phenotypic changes in HL60 cells resulting from long-term rGL-7 treatment. (A) NBT reduction by cells treated with rGL-7 or Fab fragments of Vj41 and DH59B. Cells in each treatment were reacted with 0.5% NBT solution at 37°C for 30 min and then stained with the May–Grünwald–Giemsa method. (B) Down-regulation of C-Myc expression. HL60 cells were treated with rGL-7, Vj41, DH59B, or ATRA for 36 h as described in the text. Nuclear fraction from HL60 cells was examined by Western blotting with the anti-c-Myc, 9E-10. (C) Surface expression of CD38 determined by mAb IOB-6 immunofluorescence. HL60 cells were stimulated with rGL-7 (1 μg per 10⁶ cells) or 0.1 μM ATRA for 48 h, stained with mAb IOB-6, followed by FITC-conjugated anti-mouse IgG, then analyzed by using a flowcytometer CytoAce 150. (D) Induction of NAD⁺ glycohydrolase activity by rGL-7. HL60 cells were stimulated with ≈0.4–4μg/ml rGL-7. Aliquots (10⁵ cells, 100 μl) of cell suspensions were used for analysis of NAD⁺ glycohydrolase activity.