Expert view: Reviewing the biggest innovations in antibody screening

Many large pharmaceutical, biopharmaceutical, and biotech companies have shifted resources into these modalities; making therapeutic antibodies and the downstream products based on them, like bi-specifics and CAR-T cells, the fastest growing segment in the industry. At the heart of this process is antibody screening, where target antigens are systematically exposed to a library of antibody-containing supernatants with the aim of finding ones that bind to them. One of the biggest innovations in antibody screening is the use of high-throughput flow cytometry.

Historically, the Enzyme-Linked Immunosorbent Assay (ELISA) was the assay format of choice and could be detected relatively quickly, easily, and with high throughput using a standard plate reader. However, this method cannot ‘multiplex’ multiple binding events, uses a large amount of purified protein, and can destroy potentially important binding areas (epitopes) when attaching the proteins to the plastic wells. Multiplexing is important when creating assays with internal controls for specificity or to evaluate species cross-reactivity.

Traditional flow cytometry could overcome the limitations of ELISA by using antigens expressed on cell surfaces to save precious epitopes and by multiplexing cell populations expressing different antigen controls or species isotypes in the same wells. These advantages drove many antibody screeners away from ELISA to traditional flow cytometry, only to find that they lost the speed, ease of use, and throughput advantages they had with the plate reader.

Recently, the development of high-throughput flow cytometry tools like the IntelliCyt® iQue Screener PLUS that combine the high-content multiplexing capability of the flow cytometer with the speed, ease of use, and throughput of a plate reader are giving the antibody screening community the platform they need to ramp up biologics discovery.