HuCAL Technology

The HuCAL (Human Combinatorial Antibody Library) technology is a unique and innovative concept for the in vitro generation of highly specific and fully human antibodies.

HuCAL GOLD Our key technology

In the HuCAL GOLD library, the structural diversity of the human antibody repertoire is represented by seven heavy chain and seven light chain variable region genes, giving rise to 49 frameworks in the master library. Highly variable genetic cassettes (CDRs – Complementarity Determining Regions) are then superimposed on these frameworks to mimic the entire human antibody repertoire (Fig 1). More than 15 billion functional human antibody specificities in Fab format are already prefabricated and available in HuCAL phage libraries.

Selecting your antibodies from 15 billion candidates

Your antigen enters the automated panning process (AutoPan), where it is immobilized in 384-well microplates for screening against antibody-displaying phage. A 0.5 mg antigen sample is usually enough for comprehensive screening. CysDisplay technology (Fig 2) provides simple elution of high-affinity binders and reduces the number of potential antibody candidates to several hundreds or thousands of sequences. These candidates are then screened in a robust 384-well ELISA (AutoScreen). Positive clones are automatically forwarded for further validation, sequenced, and entered into the central database.

Generating your monoclonal antibody

Unique antibody candidates from the screening process are expressed in bacteria and affinity purified on a micro scale for QC and specificity testing. We screen all purified antibodies against the antigen plus several unrelated proteins, or on request, against closely-related proteins supplied by the customer. Micropurified antibodies are then sent to the customer for functional testing in their in-house applications. Selected antibodies are then purified in larger scale. All antibodies can be ordered in large scale at any time.

Antibody formats the choice is yours

The basic antibody format is a monovalent Fab fragment, which can be easily converted into a bivalent Mini-Antibody format (Fig 3). While monovalent Fab fragments are smaller, Mini-Antibodies show up to 10-fold higher avidity than monovalent Fabs in some applications, mimicking the bivalent binding behavior of IgGs. Fab fragments and Mini-Antibodies are ideal for use in most applications and offer significant advantages over full antibodies due to their smaller size and lower cross-reactivity. However, if full-size antibodies are required, HuCAL Fabs can easily be converted into IgGs and expressed in mammalian cell lines.