A triallelic Fc gamma receptor type IIIA polymorphism influences the binding of human IgG by NK cell Fc gamma RIIIa.
A donor-dependent difference in electrophoretic mobility of deglycosylated released Fc gamma RIIIa derived from NK cells and macrophages was observed. We investigated whether this was based on a polymorphism of the Fc gamma RIIIA gene. Cloning and sequencing of Fc gamma RIIIa-encoding cDNA derived from an apparently heterozygous donor showed one single nucleotide substitution at position 230 (T-->G), which was responsible for a leucine (L)-->arginine (R) substitution at position 48 in the first extracellular Ig-like domain (EC1) of Fc-gamma RIIIa and caused a higher electrophoretic mobility of Fc gamma RIIIa. An allele-specific primer annealing PCR assay was developed to amplify specifically an Fc gamma RIIIA gene-derived fragment, which was digested with AciI (recognizing G230) or MnlI (recognizing T230). MnlI restriction analysis revealed the presence of a third Fc gamma RIIIa allele with a T230-->A substitution, which predicts a change of 48-leucine into 48-histidine (H). A gene frequency of 86% for the T230 (48-L) allele, 6% for G230 (48-R), and 8% for A230 (48-H) was found. A significantly different genotype distribution was found among 12 unrelated Caucasian Fc gamma RIIIB gene-deficient donors. Fc gamma RIIIa-48R and Fc gamma RIIIa-48H showed a higher binding capacity of human (h)IgG1, hIgG3, and hIgG4 compared with Fc gamma RIIIa-48L. Finally, the CD16 mAbs 1D3 and MEM154 bound more strongly and Leu11c (B73.1) bound less to the newly identified Fc gamma RIIIa isoforms.
de Haas
M
M
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam.
Koene
H R
HR
Kleijer
M
M
de Vries
E
E
Simsek
S
S
van Tol
M J
MJ
Roos
D
D
von dem Borne
A E
AE
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D001666:Binding Sites, Antibody / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic / Q000276:immunology*; D017452:Receptors, IgG / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*
D007074:Immunoglobulin G; D017452:Receptors, IgG