Biallelic neutrophil Na-antigen system is associated with a polymorphism on
the phospho-inositol-linked Fc gamma receptor III (CD16)
TW Huizinga, M Kleijer, PA Tetteroo, D Roos and AE von dem Borne
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service,
Amsterdam.
Neutrophils express two distinct types of receptor for the Fc region of
IgG, FcRII and FcRIII, in amounts of 10,000 to 20,000 FcRII (40 Kd) and
100,000 to 200,000 FcRIII (50 to 80 Kd) per neutrophil. We showed that the
FcRIII exhibits genetically determined heterogeneity, detectable by
differences in electrophoretic mobility with sodium dodecyl sulfate (SDS)
as well as by reaction with antibodies against the biallelic
neutrophil-specific antigen system NA. FcRIII was precipitated with an
FcRIII-specific monoclonal antibody (MoAb) from the neutrophils of 35
donors. NA1NA1 donors expressed an FcRIII with a molecular weight (mol wt)
of 50 to 65 Kd, NA1NA2 donors expressed an FcRIII with a mol wt of 50 to 80
Kd, and NA2NA2 donors expressed an FcRIII with a mol wt of 65 to 80 Kd.
Statistical analysis showed that the electrophoretic heterogeneity
corresponds with the NA polymorphism (k = 1). Sequential
immunoprecipitation with a MoAb against NA1 and a MoAb against anti-
FcRIII, followed by SDS-polyacrylamide gel electrophoresis (PAGE), showed
that NA1-FcRIII is distinct from NA2-FcRIII. Moreover, immunoprecipitation
with a MoAb against NA1 yielded a protein of 50 to 65 Kd, and
immunoprecipitation with human anti-NA2 sera or an MoAb against NA2 yielded
a protein of 65 to 80 Kd. Preincubation of NA1NA2 neutrophils with F(ab')2
fragments of an MoAb against anti-NA1 reduced binding of IgG dimers to
these cells with about 50%, whereas it completely prevented binding of the
dimers to NA1NA1 neutrophils. Inhibition experiments with the MoAb against
NA2 yielded the same results for NA1NA2 cells, whereas binding of IgG
dimers to NA2NA2 cells was completely prevented. Thus, the products of both
NA alleles bind IgG. Immunoprecipitation from the medium of neutrophils
either stimulated with formyl- methionyl-leucyl-phenylalanine (FMLP) or
treated with glycosyl-phosphatidyl-inositol-specific phospholipase C (GPI-
PLC) showed that both the NA1-FcRIII and the NA2-FcRIII are released from
the cell surface, indicating that both forms of FcRIII have some structural
features in common. Deglycosylation of FcRIII from homozygous donors
yielded material that showed several bands on SDS- PAGE. GPI-PLC treatment
of neutrophils indicated that all of this material is phosphatidyl-inositol
linked.
Volume 75,
Issue 1,
pp. 213-217,
01/01/1990
Copyright © 1990 by The American Society of Hematology
