Research and Purification Reagents
A rate limiting step in drug development can often be the production of an affinity reagent that can be used to detect the target protein in standard laboratory assays: immuno-fluorescence, immuno-blotting and immuno-histochemistry for example.
By avoiding the use of an in vivo selection step, Affimers are not limited by the conservation between human and animal proteins. This can lead to savings in time, is more cost-effective, and can enable the simultaneous detection of binders to multiple targets.
Protein engineering enables the addition of a range of detection tags to each Affimer, tailoring the reagent to each assay.
Affimers represent a rapid, cost-effective and flexible alternative to antibodies in biological and pharmaceutical research and Avacta is developing Affimers for R&D and for purification applications in Avacta Analytical’s markets.
Diagnostics
Like antibodies, Affimers use three recognition surfaces to bind their targets, giving high affinity and specificity.
Unlike antibodies, Affimers lack a constant region for interaction with the immune system. Instead, we add to Affimers one of a range of specific tags or domains compatible with a range of detection protocols.
This enables inexpensive, high throughput expression of Affimers for diagnostic applications based on immunoassays. When combined with their exceptionally high stability at surfaces, this renders Affimers ideally suitable for multiplexed plate or array based diagnostic assays.
Avacta is developing Affimers for diagnostics in its Avacta Animal Health products and markets and will, in the future, consider human diagnostics applications.
Protein Microarrays
Affimers remain functional when immobilised on surfaces and provide a very wide range of specific binding capabilities which make them ideal as affinity reagents for the emerging application of protein microarrays.
Protein microarrays are currently dominated by antibodies which often become inactive when on surfaces, are difficult and expensive to develop and have limited availability. The development of cost effective protein microarrays with wide functionality is limited by the dependence on antibodies as the binding agents.
Affimers therefore offer a very exciting alternative to antibodies and Avacta is developing a range of Affimers for protein microarrays intended to address drug and biomarker discovery applications in Avacta Analytical’s markets. In future Avacta will address diagnostic applications of Affimer based microarrays.
Therapeutics
Affimers are derived from a natural human protease inhibitor which confers on Affimers a high degree of biophysical stability, potentially enabling a variety of routes of administration.
The parent protein has been engineered to lack detectable affinity for all human proteins, minimising the risk of off-target effects and ensuring that each Affimer will spend more time bound to its target rather than to irrelevant interactors.
Each Affimer can present multiple independent interaction surfaces, and they are readily multimerised, enabling, for example, dual-specificity targeting.
Affimers represent a new class of therapeutic proteins designed to maximise therapeutic efficacy and minimise unwanted side effects.
Avacta does not develop therapeutic agents and is seeking licensing partners for the Affimer intellectucal property for therapeutic applications.