Figure 3.
IL-15 can bypass the developmental block of NK cells in LTα−/− mice. (A) When BM cells are cultured in vitro for 7 days with recombinant IL-15, equal numbers of NK1.1+CD3− cells are induced from wt and LTα−/− BM (5.4–5.6 × 106 cells). (B) NK1.1+CD3− cells induced in vitro from LTα−/− (□) and wt (⋄) BM show similar natural killing activity against YAC-1 cells. (C) Expression of IL-15 mRNA in BM cells. Total RNA was prepared from freshly isolated BM cells or BM cells stimulated in vitro with lipopolysaccharide and IFN-γ. IL-15 mRNA was quantitatively analyzed by RNase protection assay. Equivalent amounts of mRNA for glyceraldehyde-3-phosphate dehydrogenase were observed in all four samples.