- Ferlazzo G, Pack M, Thomas D, Paludan C, Schmid D, Strowig T, et al. Distinct roles of IL-12 and IL-15 in human natural killer cell activation by dendritic cells from secondary lymphoid organs. Proc Natl Acad Sci U S A. 2004;101:16606-11 pubmed..These results identify secondary lymphoid organs as a potential DC/NK cell interaction site and identify the distinct roles for DC-derived IL-12 and IL-15 in NK cell activation. ..