NK cell expansion in miR-155 tg mice. (A) NK1.1⁺CD3⁻ FACS-sorted NK cells from spleen of wt and miR-155 tg mice were analyzed for miR-155 expression by real-time RT-PCR. This experiment is representative of 6 performed with similar results. Results are expressed as the mean ± SEM of triplicate wells. (B) Freshly isolated splenocytes of wt and miR-155 tg mice were stained with anti-NK1.1 and anti-CD3 Abs and analyzed by flow cytometry for percentage of NK1.1⁺CD3⁻ NK cells. (C) The absolute number of NK cells was calculated in spleens of wt vs miR-155 tg mice. The graph summarizes data from 4 wt and 2 miR-155 tg littermate mice. *Statistically significant; see text for details.