NK cells and NK cell activity in NOD/Shi-

scid mice with or without anti-asialo GM1 antibody, NOD/SCID/γ$cnull$, and NOD/SCID/β2m^null mice. (A) Spleen cells from mice were stained with streptavidin-FITC and biotin-labeled anti-pan NK cell antibody. No NK cells were observed in spleen cells from NOD/SCID/γ$cnull$ mice or from NOD/Shi-scidmice treated with anti-asialo GM1 antibody. (B) Spleen cells from mice treated with poly I:C 2 days before the assay were used. The formula for percentage cytotoxicity is described in “Materials and methods.”