VLR Recognition of TLR5 Expands the Molecular Characterization of Protein Antigen Binding by Non-Ig-based Antibodies. Issue 9 (27th April 2018)

• Record Type: Journal Article
• Authors: Gunn, Robin J.; Herrin, Brantley R.; Acharya, Sharmistha; Cooper, Max D.; Wilson, Ian A.
• Is Part Of: Journal of molecular biology. Volume 430:Issue 9(2018)
• Page Start: 1350
• Page End: 1367
• Publication Date: 2018-04-27
• Subjects: VLR variable lymphocyte receptor -- Ig immunoglobulin -- LRR leucine-rich repeat -- LRRNT N-terminal LRR cap -- LRRV variable LRR -- LRRVe LRRV-end -- CP connecting peptide -- LRRCT C-terminal LRR cap -- CT-loop variable insert -- TLR toll-like receptor -- BclA Bacillus collagen-like protein of anthracis spores -- DAMP damage-associated molecular pattern -- ECD extracellular domain -- RA rheumatoid arthritis -- YSD yeast surface display -- dr Danio rerio -- MACS magnetic-activated cell sorting -- FACS fluorescence-activated cell sorting -- ITC isothermal titration calorimetry -- EDC/NHS (1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide; innate immunity -- antigen binding -- leucine-rich repeat -- protein–protein complex -- X-ray crystallography; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2018.03.016
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Variable lymphocyte receptors (VLRs) are unconventional adaptive immune receptors relatively recently discovered in the phylogenetically ancient jawless vertebrates, lamprey and hagfish. VLRs bind antigens using a leucine-rich repeat fold and are the only known adaptive immune receptors that do not utilize an immunoglobulin fold for antigen recognition. While immunoglobulin antibodies have been studied extensively, there are comparatively few studies on antigen recognition by VLRs, particularly for protein antigens. Here we report isolation, functional and structural characterization of three VLRs that bind the protein toll-like receptor 5 (TLR5) from zebrafish. Two of the VLRs block binding of TLR5 to its cognate ligand flagellin in functional assays using reporter cells. Co-crystal structures revealed that these VLRs bind to two different epitopes on TLR5, both of which include regions involved in flagellin binding. Our work here demonstrates that the lamprey adaptive immune system can be used to generate high-affinity VLR clones that recognize different epitopes and differentially impact natural ligand binding to a protein antigen. Graphical Abstract: Highlights: VLR antibodies in jawless fish use an LRR framework for antigen recognition. Three VLRs with high affinity for TLR5 were identified from immunized lamprey. VLRs block TLR5 binding to flagellin in cell-based assays. Crystal structures revealed two different epitopes on TLR5. Molecular recognition of protein antigens by non-Ig antibodies