HUMAN-DIVERSITY IN KILLER-CELL INHIBITORY RECEPTOR GENES

The presence and expression of killer inhibitory receptor (KIR) and CD 94:NKG2 genes from 68 donors were analyzed using molecular typing tech niques. The genes encoding CD94:NKG2 receptors were present in each pe rson, but KIR gene possession varied. Most individuals expressed inhib itory KIR for the three well-defined HLA-B and -C ligands, but noninhi bitory KIR genes were more variable. Twenty different KIR phenotypes w ere defined. Two groups of KIR haplotypes were distinguished and occur red at relatively even frequency. Group A KIR haplotypes consist of si x genes: the main inhibitory KIR, one noninhibitory KIR, and a structu rally divergent KIR. Allelic polymorphism within five KIR genes was de tected. Group B comprises more noninhibitory KIR genes and contains at least one additional gene not represented in group A. The KIR locus t herefore appears to be polygenic and polymorphic within the human popu lation.