IgM and IgA purification made simple

The Bio Affinity Company (BAC) has introduced two new products for scientists who need to purify hard-to-separate antibodies such as immunogloblins A and M.

The CaptureSelect IgA and IgM affinity products are a one-step purification process that immediately cuts down on the complex multi-step processes that characterise similar products on the market.

Purification of IgA and IgM antibodies is recognised as a particularly difficult process.

The IgA affinity matrix contains an affinity ligand that binds to a unique domain that is present on all subclasses of human IgA, with no cross reactivity with IgM or IgG. Likewise the IgM affinity matrix contains an affinity ligand that is directed towards a unique domain that is present on both human and mouse IgM antibodies, and offers no cross-reactivity with human or mouse IgA or IgM. BACs claim the products have been specifically selected and designed to bind specially to particular antibodies, an approach that is in contrast to other traditional purification media (e.g. Protein A), which have a reasonably good specificity for a given antibody.

" The products in our CaptureSelect Antibody Toolbox range simplify and streamline the purification of antibodies in the lab ," said Mark ten Haaft, Director of Ligand Application at BAC.

" We have developed standardised protocols that enable researchers to follow a simple one-step process with no need for method testing or lengthy optimisation steps.

Additionally, the unique specificity of the products provides researchers with total confidence that the affinity matrix they choose will be a perfect match for their target. "

BAC's main competition in this area seems to be GE Healthcare with its Capto Adhere range.

Intended for use after the initial Protein A capture step-for " polishing " monoclonal antibodies-it's a new member of GE's range of Capto ion exchange media.

The ligand within Capto adhere is a strong multimodal ion exchanger.

It removes contaminants such as DNA, host cell proteins, leached Protein A, viruses, dimers, and aggregates in a single step.

Capto adhere can also be followed by anion or cation exchange chromatography for polishing; for this, GE offers their anion exchanger Capto Q, and cation exchanger Capto S. Therapeutic monoclonal antibodies (Mabs) currently command a worldwide market of more than $15bn.

The figure is expected to grow to exceed $30bn by 2010. .

Attention has rightly shifted on the need for advanced purification tools and platforms to enhance the speed, robustness and scalability of the downstream processes required for mAb manufacturing.

In recent years, new technologies and products have been introduced that not only target key processes in mAb purification (including product harvest, capture and polishing), but also offer scalable solutions.

Laurens Sierkstra, CEO of BAC, commented: " We are very pleased to add these products to our off-the-shelf range and address such an important market need.

The CaptureSelect Antibody Toolbox allows us to make the technology that we have already proven at industrial scale, accessible at an R&D scale for bench research ."