A breakdown of your burning nAb questions

Allele Biotechnology just released its latest batch of nAbs (nano antibodies), the first wave on a long list of new antibodies to come! You might have a few questions about how these “antibodies of the future”, as we call them, can help your research:  What can I use them for?  How much should I use?  And how do they work compared to a traditional antibody? 
 
To answer these questions, we need to first discuss some antibody basics.  Conventional antibodies (your typical mouse or rabbit derived antibody) have a “Y” shape and tightly bind targeted antigens as a result of two factors.  The first is affinity between each monomer Fab fragment and the antigen.  The second is the fact that traditional antibodies are di-valent, i.e. they have two identical binding sites for each antigen, which is known as avidity. 
 
When developing a nano-antibody, we screen and select our clones to have extremely high affinity as a monomer.  This is because nAbs are mono-valent VHH fragments. The intrinsic high affinity VHHs possess for their antigens can make up for the lack of multivalency (avidity).  As a result, nAb binding is often superior to conventional antibody binding, which leads to superior performance in a variety of biological assays (immunoprecipitation, immune-staining, FACS staining, immunofluorescent imaging, etc.). 
 
Each nAb is roughly one tenth (1/10) the size of a traditional antibody.  The small size and stable conformation of nano-antibodies enable pinpointed localization of target antigens and allow access to antigen and cellular regions generally restrictive to larger antibodies. As a result of this smaller size, when measured by weight 1mg of a nAb is equivalent to 5 – 10mg of a traditional antibody (the lower end takes di-valency into account).  When substituting a nAb for a traditional antibody you can use as little as one tenth (1/10) the amount by weight. 
 
There are a couple of different ways to use nAbs.  The first is immobilizing the nano-antibody on a resin (i.e. magnetic-agarose resin) for immunoprecipitation.  The nano-antibody will not be released from the resin upon elution so you will not have contaminating bands.  The second method is direct labeling with a fluorescent dye or hapten.  nAb’s are compatible with standard NHS-ester amine chemistry binding.  This enables single or multiple fluorophore labeling per antibody.  Moving forward, additional platforms will be released that allow for a more flexible and adaptable labeling system, allowing you to harness nAbs for any biological assay you can imagine.  Have some suggestions? Don’t hesitate to let us know by emailing at nAb@allelebiotech.com. Or call 858-587-6645 and ask for a nAb expert.

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Friday, September 4th, 2015 nAb: Camelid Antibodies, Nanobodies, VHH

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