Molecular characterization of antigenic polymorphisms (Ond(a) and Mart(a)) of the beta 2 family recognized by human leukocyte alloantisera.
We show that the previously described alloantisera Ond and Mart, which recognize the alloantigens Ond(a) and Mart(a), react with polymorphic variants of alpha L and alpha M subunits of the beta 2 integrin family (CD11a and CD11b molecules). This was shown by testing the alloantisera in a monoclonal antibody-specific immobilization of leukocyte antigens, immunoprecipitation, and immunofluorescence assay against cells from normal donors and from patients with leukocyte adhesion deficiency (beta 2 intergrin deficient). To elucidate the molecular basis of the Ond(a) and Mart(a) alloantigens, RNA was isolated from mononuclear leukocytes derived from individuals of known serologic phenotype. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to amplify the entire coding region of the alpha L and alpha M mRNAs. The Ond(a) antigen was found to be due to a G2466C substitution in the DNA coding for the alpha L subunit, which predicts an Arg766Thr amino-acid polymorphism. The Mart(a) antigen was also found to be due to a single nucleotide substitution (G302A) in the DNA coding for the alpha M subunit, which predicts an Arg61His amino acid polymorphism. Using allele-specific restriction enzyme analysis, the association between point mutations and phenotypes was confirmed. The localization of these alloantigens on integrin molecules further illustrates the polymorphic nature of this class of proteins. Whether the polymorphisms influence the adhesive capacity of the leukocyte integrins remains to be investigated.
Simsek
S
S
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, University of Amsterdam, The Netherlands.
van der Schoot
C E
CE
Daams
M
M
Huiskes
E
E
Clay
M
M
McCullough
J
J
van Dalen
C
C
Stroncek
D
D
von dem Borne
A E
AE
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D018821:CD18 Antigens / Q000235:genetics / Q000276:immunology*; D003179:Complement C3b / Q000235:genetics* / Q000276:immunology; D017931:DNA Primers / Q000737:chemistry; D018604:Epitope Mapping; D005260:Female; D006801:Humans; D007518:Isoantibodies / Q000276:immunology; D007519:Isoantigens / Q000235:genetics*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics* / Q000276:immunology; D008297:Male; D008969:Molecular Sequence Data; D010375:Pedigree
D018821:CD18 Antigens; D017931:DNA Primers; D007518:Isoantibodies; D007519:Isoantigens; D016169:Lymphocyte Function-Associated Antigen-1; D003179:Complement C3b