FUNCTIONALLY AND STRUCTURALLY DISTINCT NK CELL-RECEPTOR REPERTOIRES IN THE PERIPHERAL-BLOOD OF 2 HUMAN DONORS

The expression of KIR and CD94:NKG2 receptors was determined for more than 100 natural killer (NK) cell clones obtained from two blood donor s who differ in their HLA class I and KIR genes. More than 98% of the clones were inhibited by individual autologous class I allotypes, and every clone was inhibited by the combination of autologous allotypes. The patterns of inhibition correlate with expression of inhibitory rec eptors of defined specificity. One donor possesses three class I ligan ds for KIR, and a majority of NK cells use KIR as their inhibitory rec eptor; the second donor possesses only a single ligand for KIR, and a majority of NK cells use the more broadly reactive CD94:NKG2a as their inhibitory receptor. Because of these differences, the first donor ha s subpopulations of NK cells that kill cells of the second donor, wher eas the NK cells of the second donor are universally tolerant of cells from the first donor.