Reasons for Using Recombinant Antibodies

Reproducibility

Animal-derived antibodies are a major contributor to the reproducibility crisis in research.1 They often show poor specificity or fail to recognise their targets. In a systematic analysis of 185 commercially available hybridoma monoclonal antibodies, one-third were not reliably monospecific.2  A Nature article in which more than 100 academic and industry scientists called for an international shift to the use of recombinant antibodies (rAbs) highlighted key advantages, including improved reliability and reduced lot-to-lot variability of affinity reagents.3 The authors cited a large-scale validation study showing that only approximately 49% of commercially available, non-recombinant antibodies could be confirmed to specifically recognize their intended targets.4

The use of faulty antibodies can cost laboratories thousands of dollars a year and “trigger junk-data avalanches through the literature”.5 Select publications describing how undefined, animal-derived antibodies have inhibited progress in identifying and treating disease include the following:

  • Vaezi et al. reported that an animal-derived monoclonal antibody used in a majority of studies to measure an antigen previously thought to be predictive of treatment outcome for non‐small cell lung cancer was not monospecific and that another target indicated clinical outcome.6
  • Andersson et al. found that antibodies used over the past 20 years did not specifically target oestrogen receptor β (ERβ), a historically important target in breast cancer research, and that ERβ protein is not found in breast tissue.7
  • Gilda et al. showed that five commercial ubiquitin antibodies resulted in different detection of free ubiquitin or ubiquitinated proteins in western blot analysis. Furthermore, large variability was seen in the ability of six commercial antibodies to detect a protein modifier.8
  • Elliott et al. found that anti-erythropoietin receptor (EpoR) antibodies were not specific in immunohistochemical methods, resulting in unreliable results from cancer studies reporting EpoR expression.9
  • Baker recounts how years of research and millions of dollars were wasted on a cancer treatment that relied on antibodies that proved to be unreliable.1

Scientific Advantages

The need for higher-quality affinity reagents has prompted the development of sequence-defined, animal-free rAbs. Their advantages include the following:

  • Because the DNA sequence is known, the same antibody can be resynthesized in perpetuity without lot-to-lot variability.10
  • Antibody selection conditions can be adjusted to select for a specific epitope structure, antibody conformation, and cross-reactivity.10,11
  • Negative selection techniques can exclude antibodies that react with molecules similar to the selected antigen.11
  • Because they are independent of a biological immune response, antibodies can be developed to target toxic and pathogenic antigens.10,12
  • Antibodies can be developed to target molecules with low molecular weight, such as haptens, that fail to elicit an immune response in animals.13 They can also be produced to target peptides and non-biological targets, including metals and carbon nanotubes.14
  • They are available in multiple sizes – from fragments to full-length antibodies.10
  • They can be reformatted into different structural formats (e.g., IgG, Fab, or scFv) and further engineered (e.g., via sequence modification or Fc design), enabling the same antigen-binding specificity to be tailored for diverse applications and functional properties.15 
  • They are broadly applicable and can be used in immunohistochemistry, western blot, ELISA, flow cytometry, and immunoprecipitation.10
  • Because they are already of human origin, they do not have to be humanised for therapeutic use.10

For more information, see Resources.

Economic Reasons

Considerable cost savings are associated with the more reproducible research that will result from using higher-quality, animal-free rAbs. Bradbury and Plückthun estimate that US$800 million is wasted annually worldwide on unreliable antibodies, US$350 million of that in the US.3

Rapid expansion of catalogue rAbs is making them increasingly accessible at competitive costs. An article in ALTEX demonstrates that existing catalogue recombinant alternatives can already replace many widely used research antibodies, reducing the need for custom development and enabling more immediate adoption of higher-quality reagents.  

While costs are similar for previously produced “catalogue” animal-derived antibodies and rAbs, the initial investment in new, custom-made antibodies is high, whether they are generated using animals or non-animal methods.10 Because animal-derived antibodies have been produced for decades, many do not have to be custom-made, whereas many rAbs are not yet available in catalogues and so must be custom-made. Therefore, initially, the production of new rAbs can be expensive, as is the case for many forms of new technology, but the price should decrease as more companies and universities become involved in their development and use.

Ethical Reasons

Millions of animals are used to produce antibodies every year. Animals used in antibody production are subjected to invasive and painful procedures. Furthermore, numerous animal welfare violations have been uncovered at facilities that produce antibodies.

In the ascites method of monoclonal antibody production, tumour development, accumulation of ascites fluid, and multiple fluid draws can cause the animals, usually mice, considerable pain and distress. It has been reported that they are unable to eat, walk, or breathe properly. A number of countries, such as Australia, Canada, Germany, the Netherlands, Switzerland, and the UK, have restricted or banned the production of antibodies via the ascites method because of animal welfare concerns.16–18