Molecular characterization of antigenic polymorphisms (Ond(a) and Mart(a))
of the beta 2 family recognized by human leukocyte alloantisera
S Simsek, CE van der Schoot, M Daams, E Huiskes, M Clay, J McCullough, C van Dalen, D Stroncek and AE von dem Borne
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service,
University of Amsterdam, The Netherlands.
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.
Volume 88,
Issue 4,
pp. 1350-1358,
08/15/1996
Copyright © 1996 by The American Society of Hematology
