Efficacy of NK cell depletion with anti-asialo GM1 antibody. The frequency of CD3- CD49b+ NK cells in the spleens of A. BALB/c mice and B. BALB/c scid mice that received i.p. injections of 1.0 mg per day control rabbit IgG, as compared to scid mice treated with C. 0.32 or D. 1.0 mg per day of rabbit anti-asialo GM1. Mice were treated with antibody on Days 0 and 3, and spleen WBCs were isolated on Day 4 for flow cytometric analysis with FITC-labeled anti-CD3 and PE-labeled anti-CD49b. The frequency of NK cells (upper left quadrant) and CD3+ T cells are indicated on each graph. Results are representative of three independent experiments.