Nanobodies™ by Ablynx

Red Herring has an interesting article about the Belgian company Ablynx, a biotech firm that has developed and patented antibodies that are much smaller and more stable than monoclonal ones. The breakthrough for the company came with the recognition that camelidae (camels and llamas) have functional antibodies that completely lack light chains.
The company explains its technology, dubbed Nanobodies™:

Nanobodies™ are antibody-derived therapeutic proteins that contain the unique structural and functional properties of naturally-occurring heavy-chain antibodies. The Nanobodies™ technology was originally developed following the discovery that camelidae (camels and llamas) possess fully functional antibodies that lack light chains. These heavy-chain antibodies contain a single variable domain (VHH) and two constant domains (CH2 and CH3). Importantly, the cloned and isolated VHH domain is a perfectly stable polypeptide harboring the full antigen-binding capacity of the original heavy-chain antibody. The unique structural and functional properties of this newly discovered VHH domain are the basis of Ablynx’s Nanobodies™.
Ablynx’s Nanobodies™ combine the advantages of conventional antibodies with important features of small molecule drugs. Like conventional antibodies, Nanobodies™ show high target specificity and low inherent toxicity; however, like small molecule drugs they can inhibit enzymes and can access receptor clefts. Furthermore, Nanobodies™ are extremely stable, can be administered by means other than injection, and are easy to manufacture.
Ablynx’s Nanobodies™ have a high homology with the VH domains of human antibodies and can be further humanized without any loss of activity. Importantly, Nanobodies™ have an extremely low immunogenic potential. In initial primate studies with Nanobodies™ lead compounds, repeated administration did not yield a detectable immune response.

According to Red Herring, the company has “developed nanobodies that work against more than 20 different disease targets including rheumatoid arthritis, Alzheimer’s disease, and some cancers.”
The article at the Red Herring…
Company’s technology page…