Characterization of Fc epsilon RI gamma in human natural killer cells

Abstract

We report the characterization of the Fc epsilon RI gamma chain which associates with the transmembrane form of CD16 to form the low affinity receptor for IgG (Fc gamma RIII) expressed on human natural killer (NK) cells. cDNA cloning and sequence analysis of Fc epsilon RI gamma from a polyclonal CD3-CD16+ NK line established that this molecule is identical to Fc epsilon RI gamma previously identified in human basophils as part of a high affinity receptor for IgE. Polymerase chain reaction analysis of Fc epsilon RI gamma gene expression in a series of CD3+CD16- and CD3-CD16+ NK clones reveals that Fc epsilon RI gamma is not directly linked to NK activity since clones of the CD3+CD16- phenotype lack Fc epsilon RI gamma RNA but nevertheless mediate cytotoxicity. Taken together, these results demonstrate that the Fc epsilon RI gamma molecule is expressed in various types within the hematopoietic system as part of multimeric surface receptors involved in different biological functions.