SLP-76 KO NK cells cannot prevent tumor engraftment in vivo. Ly49D⁺ splenic NK cells from WT, SLP-76 KO, or RAG KO mice were enriched and expanded in IL-2 for 6 days. Luciferase-expressing CHO cells were injected into NSG mice followed by injection of PBS (∅) or the indicated NK-cell type. (A) Images were taken on days 0, 3, 7, and 10. One representative of 3 independent experiments is shown. (B) Average tumor radiance data compiled from all experiments (n = 6 for WT, n = 7 for RAG KO, n = 10 for SLP-76 KO, and n = 9 for PBS) are expressed as mean ± standard error of the mean. * indicates significance of P < .05 for WT vs SLP-76 KO, WT vs PBS, RAG KO vs SLP-76 KO, and RAG KO vs PBS.