Target Indifferent Approach

The term 'target indifferent approach' describes the Center for Therapeutic Antibody Development's (CTAD) novel protocol for the production of mAbs in cases where the target protein is unknown. This protocol would be advantageous when a reagent is needed that:

1. Differentiates functional phenotypes when novel surface proteins are unknown (i.e. differentiation of islet cells)
2. Acts as a diagnostic marker/prognostic indicator (i.e. cancer cells)
3. Performs a function, but the mechanism is unknown (i.e. blocking viral entry by binding to a host protein).

CTAD's target indifferent approach relies on the observation that mice can be efficiently immunized to complex or multiple antigens of a cell simultaneously by the injection of cellular vesicles. These vesicles, comprised of transport vesicles as well as other small orgenelles with a lipid bilayer, display membrane proteins in their native tertiary structure. Our experience is that immunization in this manner results in mAbs that have superior binding to the native proteins. After the antibodies of interest are established, their targets can be identified by Immunoprecipitation and mass spectrometry. These antibodies are designed for flow cytometry, immunohistochemistry, immunoprecipitation -in low or non denaturing conditions - as well as in vivo imaging and therapeutics. For a successful project using this approach, a high throughput screening assay is essential.

Vesicle preparations can also be used when the protein targets are known but native protein folding is essential (in vivo/therapeutic targets). In these cases, the target protein can be overexpressed in the vesicles for more specific antibody production.