Purification, Conjugation, Fragmentation

Antibody purification

Each antibody reacts differently to the purification techniques to which it is subjected. A suitable purification is the best compromise between the degree of purity and the yield.

  • Pre-purification of immune sera: debribrination, delipidation, precipitation with ammonium sulphate, caprylic acid or ethyl precipitation (Cohn methods).
  • Gel filtration: reserved for IgM, preserves the activity of antibodies.
  • Ion exchange chromatography: “soft” technique, usable for all IgG subclasses, particularly suitable for monoclonals.
  • Chromatography on protein A or G: allows to obtain high degrees of purity but the elution conditions can affect the activity of certain IgGs.
  • Immunoaffinity chromatography: the most specific of purifications, particularly suitable for polyclonal antibodies, this technique however requires a sufficient quantity of antigenic fraction.

Antibody conjugation

You can rely on our professionnal team to quickly and efficiently label your antibodies.

Our antibody labeling service is competitive with antibody labeling kits.

We cover all your needs:

  • Enzyme labeling (peroxydase, alcalin phosphatase, oxydase glucose, b-galactosidase)
  • Fluorescent labeling (Fluorescein (FITC), Cyanine, Phycoerythrin)
  • Biotynilations
  • Development of labeling protocol with all commercial labels

Antibody fragmentation

Antibody activity is supported by a small region that represents only 2% of the molecule. The rest of the molecule can lead to undesired effects :

  • in detection methods, the whole antibody can generate non-specific interactions (background signal)
  • or therapeutic use, the antibody has an immunogenicity that can cause anaphylactic shocks

The antibodies can be treated to obtain fragments F(ab’)2 or Fab. The F(ab’)2 fragments have a much better apparent affinity and hold their property of precipitation thanks to their bivalent form. The Fab fragments are monovalent. They are particularly recommended to hit hard-to-reach targets when molecule diffusion is a limiting factor.