Camelid Antibodies

When it was discovered that animals in the camel family produce antibodies with no light chains, the idea that a single-domain fragment can bind as well as a full 4-chain antibody formed a breakthrough. So far it has been a relatively less known one.

Smaller antibody fragments have been tested for therapeutic uses because classical IgG antibodies are too bulky to penetrate tissues well, and very expensive to produce. Different combinations of antigen-binding variable regions are used, e.g. scFv, Fab, diabody, all to some degree of success. In comparison, the N-terminal domain of camelid antibodies, termed VHH domain (nanobody, VHH antibody), represents a naturally evolved, only 13-15 kD in size, fully functional target binding fragment with many advantages.

The only other known species outside camelidae family that has heavy chain antibodies is particular cartilaginous fish, nurse shark. Although the arrangement of CDRs is somewhat different between the camel and shark heavy chain variable regions, they share many characteristics such as extremely high stability (maintaining functions after100 C heat and extreme pH treatment).

Accumulating reports have demonstrated the therapeutic potentials of camelid antibody-based fragments in treating cancer, neural diseases, even use in hair dandruff preventing shampoo. For basic research, the tiny antigen binders can be used as tools for quantitative pull down with unmatched efficiency, recognizing previously inaccessible enzyme cleft as antigens, and providing libraries for binding partner selection.

Allele Biotech has been working on display antibody selection from its early days through an NIH grant, and recently carried out an NIH/NCI contract for scFv yeast display.

Check out Allele’s current Camelid antibody products:

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Thursday, August 13th, 2009 nAb: Camelid Antibodies, Nanobodies, VHH

2 Comments to Camelid Antibodies

[…] produce single heavy chain antibodies that can function as 13-16kDa fragments (yes if you have read previous Allele Blogs They can easily be produced in […]

[…] through in vitro evolution [3]. They presented Nb80 on the surface of yeast using an existing yeast display system, then applied standard limited mutagenesis and magnetic separation technologies for […]

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