In the three million years that have passed since the split of the New World and Old World Camelidae, heavy chain-only antibodies have developed from the traditional immunoglobulin loci and carry certain structural changes that have been preserved in all camelid species.
Figure. Structure of heavy chain-only antibodies
Nano-antibody (Nb), also called single domain antibody (sdAb) or heavy-chain variable (VHH), derived from camelid heavy chain antibodies, is the minimum known native antigen-specific binding functional fragment, with a molecule weight of only ~15 kDa. Nbs are highly stable, durable, and soluble. Additionally, because of their small size, Nbs can bind epitopes that full-size antibodies cannot reach and pass through narrow cavities.
With a preserved disulfide bond between Cys23 and Cys94, VHHs have a normal IgV fold with nine β strands. Three hypervariable loops joined by four conserved framework sections make up the V domain, just like in conventional IgGs.
1.Nanobody Immunoassay Format: Lateral Flow Immunoassays and Diagnostic ELISAs
2.Biosensors: instantaneous results
3.In Vivo Diagnostic Imaging
1.Nanobodies Against Cancer
2.Nanobodies Against Autoimmune Diseases
3.Nanobodies Against Infectious Diseases
4.Nanobodies Against Toxins and Venoms
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