Recombinant antibodies: reproducible with tailored specificity

Recombinant antibodies give you the highest level of consistency between batches, peace of mind with an uninterrupted supply, and the ability to engineer sensitivity and specificity.

Monoclonal antibodies are typically made using B-cells from an immunized animal to form immortal hybridoma cells that secrete the desired antibody clone. This hybridoma technique produces highly consistent, specific and sensitive monoclonal antibodies in large quantities. However, over time, feeder cell lines can become unstable and the process is relatively labor-intensive and carries a risk of contamination due to its multi-step nature. There is also a growing demand for antibodies against difficult targets, ie toxins, nucleotides, and membrane-bound proteins, that can’t always be made with this in vivo model.

Recombinant antibodies overcome many of the limitations of hybridoma-production of monoclonal antibodies.

What are recombinant antibodies?

​​Recombinant antibodies are constructed in vitro and do not rely on an animal’s immune system for generation. This is done by cloning antibody genes for immune-specific heavy and light antibody chains into high-yield expression vectors. These vectors are then introduced into expression hosts (eg bacteria, yeast, or mammalian) to generate the recombinant monoclonal antibodies. Recombinant antibodies can be used wherever you would normally use a traditional monoclonal antibody.

Benefits of recombinant antibodies

Recombinant antibodies offer several advantages over both traditional monoclonal and polyclonal antibodies:

  • Improved consistency and reproducibility
    Because recombinant antibodies are developed from a unique set of genes, antibody production is controlled and reliable. Several problems with hybridoma production can be avoided, such as gene loss, gene mutations, and cell-line drift. This leads to antibodies with very little batch-to-batch variability, giving you highly reproducible results. 
  • Figure 3. Our anti-Bcl-XL recombinant rabbit monoclonal antibody - ab178844 (left) being tested on multiple sample types in western blot against a highly-cited competitor anti-Bcl-XL rabbit polyclonal antibody. Take a look at our western blot protocol.
  • Improved sensitivity and specificity
    With recombinant technology, it is easier to improve both antibody specificity and sensitivity through antibody engineering. The selection process for the desired clone occurs at both the hybridoma and recombinant cloning stages, allowing us to select the most favorable antibody qualities.
  • Ease of scalability
    With the antibody genes isolated, antibody expression can be carried out at any scale and in a shorter timeframe than traditional monoclonal technology. This means we can generate tailored antibodies in weeks rather than months.
  • Animal-free high-throughput production
    Once the antibody-producing gene is isolated, animal-free in vitro production can be implemented. For antibodies generated using our phage display technology, even the gene of the antibody can be isolated with an animal-free procedure.

Recombinant RabMAb® rabbit monoclonals

In order to provide you with antibodies that have excellent sensitivity with the highest degree of consistency, we have engineered recombinant versions of our RabMAb rabbit monoclonal antibodies. This combination delivers several unique advantages.

At the moment, we have over 10,000 recombinant RabMAb antibodies and can also offer a custom RabMAb development service.

Table 1. The benefits of recombinant antibodies and RabMAb antibodies

RabMAb rabbit monoclonal antibodies

Recombinant antibodies

Low background

High consistency and reproducibility

High specificity

Improved sensitivity

High affinity (10-12 kD possible)

Improved specificity

Diverse epitope recognition

Animal-free production

In addition to the benefits of recombinant antibodies and RabMAb antibodies, recombinant RabMAb antibodies are

Phage display technology for recombinant antibodies

In vitro phage display technology and library provide the ability to screen, validate, and manufacture recombinant monoclonal antibodies more rapidly and against especially difficult targets. For example, here’s an in vitro derived recombinant monoclonal antibody developed against Diphtheria toxin.

Figure 1. Human monoclonal IgG1 to Diphtheria toxin (ab209329): Due to toxic effects it is difficult to develop antibodies using an in vivo approach against toxins hence why we isolated an antibody using the in vitro​ phase display library.

Our phage display relies on a large library of bacteriophage particles (>1010 clones), each carrying the genetic information and the unique phenotypic binding function of one antibody clone. The libraries we make use of are M13 phagemid libraries with diversity restricted to the most variable positions in the complementary determining regions (CDRs) of natural antibody sequences. This method limits the number of parental clones in the library to less than 1%. Screen procedures are as follows:

  1. Target proteins or peptides are captured on an ELISA plate which is used to screen the phage display library
  2. Plates are washed to remove non-specific binders
  3. The specific phage display binders are subsequently eluted and transduced into bacterial cells for amplification
  4. Two additional rounds of panning/screening (steps 1 and 2) are processed to ensure each individual clone is pure
  5. Target specificity is confirmed through binding assays, such as an ELISA
  6. One the clone is isolated - the antibody gene sequence is engineered into a mammalian or bacterial expression vector for large scale manufacture of the recombinant monoclonal antibody and subsequently validated in relevant assays such as western blotting, immunofluorescence, flow cytometry, and immunohistochemistry​

Figure 2. schematic of the phage display process.

Selected references for our phage display recombinant antibody technology

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