Call for standardisation of antibodies used in research

An opinion piece in the journal Nature, representing over 100 antibody experts around the world, has called for a standardised approach to the creation and use of antibodies in research and therapeutics. Antibodies are the only widely used reagents in biological research that are not defined at the sequence level; Dr Andrew Bradbury, Professor Andreas Plückthun and 110 signatories want this to change.

The sequence of an antibody or binding reagent is like a ‘barcode’ for that reagent, ensuring that everyone can use the same reagent for the same target. Deriving the barcode involves either selecting antibodies from in vitro libraries, or cloning and sequencing antibody genes from hybridomas - the cells that traditionally make monoclonal antibodies.

For polyclonal antibodies, for example, production is based on injecting an animal with a protein and then later extracting the antibodies that the animal’s blood is carrying in response to the immunising protein. Only 0.5 to 5% of the product produced is the desired antibodies, ready to respond to the original target - the rest are antibodies already in the animals’ blood stream and represent previous immunological challenges.

Furthermore, the quality of all antibodies produced varies according to the manufacturer - most antibodies are rarely validated and between-batch differences are common, the authors note. The quality of the documentation accompanying the batches is also variable; even when it is provided, it often doesn’t correspond to the batch being supplied.

Australian signatory Associate Professor Daniel Christ, from the Garvan Institute of Medical Research, believes the lack of quality control is making reproducibility of experiments difficult, and sometimes impossible. He noted, “In many cases, the sequences that determine an antibody’s specificity have either not been defined or have not been made publicly available.”

This is causing an “enormous waste in materials, researcher time and money”, according to the researchers, which can only be stemmed by defining antibodies by their sequences and producing them de novo under standardised conditions - ie, generating antibodies or other binding reagents from scratch using methods that do not involve animal immunisation. Referring to antibodies according to the sequences encoding their various subunits, their concentrations and the standardised experimental buffers used for each assay would enable all researchers to employ the same affinity reagents under the same conditions, the authors state.

Dr Bradbury, a researcher at Los Alamos National Laboratory in New Mexico, said the new method will “not require the use of animals at all and, importantly, will directly lead to molecules with known sequences”. He acknowledged that it might cost roughly US$1billion to “generate characterised recombinant binding reagents to target the products of all human genes”, but said this would “probably be less than what is wasted worldwide on bad reagents in two or three years”.

The authors therefore call on the public funding agencies of the world’s largest economies to fund the transition to recombinant antibodies, with a goal of completing the transition within five years. “This would mirror the requirements for the past few decades that gene sequences and coordinates for new protein structures be deposited and made publicly available,” they said.