A natural killer cell that is developmentally mature and expresses a variety of inhibitory and activating receptors that recognize MHC class I and other stress related molecules. [ http://purl.obolibrary.org/obo/go/references/0000031 http://openisbn.com/search.php?q=0781735149&isbn=1/ GOC:add http://www.ncbi.nlm.nih.gov/pubmed/14685782 ]