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Isolation of an IgG anti‐B from a human Fab‐phage display library
Author(s) -
Chang Tylis Y.,
Siegel Don L.
Publication year - 2001
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.2001.41010006.x
Subject(s) - abo blood group system , phage display , antibody , epitope , hemolysis , microbiology and biotechnology , group a , group b , agglutination (biology) , panning (audio) , antigen , hemagglutination , biology , immunoglobulin light chain , rh blood group system , immunology , medicine , paleontology , zoom , lens (geology)
BACKGROUND: ABO incompatibility is a common cause for mild hemolysis in the newborn, ranging from 1 in 30 to 1 in 150 births. Fortunately, hemolysis requiring transfusion is rare and restricted to blood group O mothers, because blood group A and B individuals make poor IgG anti‐B and anti‐A responses. No human IgG ABO antibody sequences have been reported, in part because of the difficulty in obtaining human IgG hybridomas. Phage‐display technology may be able to circumvent these difficulties, but its application to carbohydrate antigens is poorly studied. STUDY DESIGN AND METHODS: A human IgG1 phage‐display Fab library was constructed from splenocytes derived from a nonhyperimmunized blood group O person, and panned against group B RBCs. RESULTS: After five rounds of panning, essentially all phage bound to group B RBCs. Nucleotide sequence analysis of a single monoclonal IgG1λ phage, FB5.7, revealed a highly mutated VH4 family heavy chain, and a nearly germline VL7 family λ light chain. The Fab agglutinated group B, but not group A, random‐donor RBCs. However, group B ELISA reactivity could be inhibited by soluble B‐trisaccharide, soluble A‐trisaccharide, galactose, and N‐acetyl galactosamine. Similarly, galactose and N‐acetyl galactosamine were able to inhibit group B RBC agglutination. CONCLUSION: FB5.7 is the first human IgG ABO MoAb described. Alhough it behaves serologically like a group B‐specific antibody, it demonstrates interaction with both the A and B epitopes. Phage‐display technology can be used to better define the relationship between antibody genotype and phenotype in anti‐carbohydrate responses in nonhyperimmunized hosts, and thus to improve our understanding of the composition of the antibody repertoire.