Cytotoxicity and TGF-β1 mRNA expression in NK-cells induced in the antitumor response of anti-CD69–treated mice. Mice treated with 200 μg of mAb CD69.2.2 or with isotype control mAb (intraperitoneally 16 hours prior to injection with the tumor cells) were injected intravenously with 5 × 10⁴ RMA-S, RM-1, or YAC-1 cells (A), intraperitoneally with 5 × 10⁴ RMA-S cells (B), or intravenously with 5 × 10⁴ RM-1 cells in both wt and CD69^-/- (KO) mice (C). RMA-S, RM-1, and YAC-1 were labeled with ⁵¹Cr prior to injection. Four hours after injection of labeled cells, the percentage of residual radioactivity remaining in the lungs (A,C) or in the peritoneum (B) was determined. Data are expressed as percentages of the total radioactivity injected (mean ± SD). (A, n = 5; B, n = 4; C, n = 4). The results are representative of 2 similar experiments. (D) Relative levels of cytokine mRNA in NK-cells purified from the peritoneum 3 days after the intraperitoneal inoculation of 10⁵ RM-1 cells into either control mice (□) or mice treated (▪) with 200 μg of mAb CD69.2.2 (on days - 1 and +1 of tumor inoculation). The data are expressed in arbitrary densitometric units normalized for the expression of GAPDH in each sample. Five animals were used per experimental group, and results are representative of 2 separate experiments. Error bars represent standard deviation (^*P < .05).