High-affinity lamprey VLRA and VLRB monoclonal antibodies.

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TitleHigh-affinity lamprey VLRA and VLRB monoclonal antibodies.
Publication TypeJournal Article
Year of Publication2009
AuthorsTasumi, S, Velikovsky, CA, Xu, G, S Gai, A, K Wittrup, D, Flajnik, MF, Mariuzza, RA, Pancer, Z
JournalProc Natl Acad Sci U S A
Date Published2009 Aug 4
KeywordsAdaptation, Physiological, Animals, Antibodies, Monoclonal, Antibody Affinity, Base Sequence, Lampreys, Molecular Sequence Data, Proteins, Receptors, Antigen

Lamprey are members of the ancestral vertebrate taxon (jawless fish), which evolved rearranging antigen receptors convergently with the jawed vertebrates. But instead of Ig superfamily domains, lamprey variable lymphocyte receptors (VLRs) consist of highly diverse leucine-rich repeats. Although VLRs represent the only known adaptive immune system not based on Ig, little is known about their antigen-binding properties. Here we report robust plasma VLRB responses of lamprey immunized with hen egg lysozyme and beta-galactosidase (beta-gal), demonstrating adaptive immune responses against soluble antigens. To isolate monoclonal VLRs, we constructed large VLR libraries from antigen-stimulated and naïve animals in a novel yeast surface-display vector, with the VLR C-terminally fused to the yeast Flo1p surface anchor. We cloned VLRB binders of lysozyme, beta-gal, cholera toxin subunit B, R-phycoerythrin, and B-trisaccharide antigen, with dissociation constants up to the single-digit picomolar range, equivalent to those of high-affinity IgG antibodies. We also isolated from a single lamprey 13 anti-lysozyme VLRA clones with affinities ranging from low nanomolar to mid-picomolar. All of these VLRA clones were closely related in sequence, differing at only 15 variable codon positions along the 244-residue VLR diversity region, which augmented antigen-binding affinity up to 100-fold. Thus, VLRs can provide a protective humoral antipathogen shield. Furthermore, the broad range of nominal antigens that VLRs can specifically bind, and the affinities achieved, indicate a functional parallelism between LRR-based and Ig-based antibodies. VLRs may be useful natural single-chain alternatives to conventional antibodies for biotechnology applications.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID19625627
PubMed Central IDPMC2722331
Grant ListAI036900 / AI / NIAID NIH HHS / United States
AI065612 / AI / NIAID NIH HHS / United States