Crucell’s proprietary MAbstract^® technology can be used to rapidly select monoclonal specificities and identify unique targets on proteins, viruses, bacteria and live cells or tissues. The technology can also be used to identify the binding regions ("epitopes") of antibodies on antigens, which can be used for the design of vaccines or small molecule inhibitors.

Antibodies are proteins produced by specialized cells of the immune system (B-cells). Their primary function is to bind and neutralize foreign targets (called antigens) such as viruses or bacteria that have invaded the body. Crucell has the expertise to isolate human antibodies of defined specificities (termed “monoclonal”), screen them for desired properties and improve them if required through molecular engineering.

Traditional technologies for generating and selecting monoclonal antibodies (mAbs) have the drawback of generating limited repertoires and using inefficient selection procedures. Crucell’s scientists have found that the combination of phage-display, MAbstract^® technology and optimized reformatting procedures results in fast recovery of monoclonal antibodies with the desired properties.

Crucell uses so-called phage-display technology for antibody discovery. A bacteriophage, or phage, is a bacteria-infecting virus that can be engineered to express part of a human antibody on its surface. The phage-display technology is used to generate large libraries of phages expressing antibodies. To identify and subsequently isolate relevant antibodies, the phage library is exposed to the target, which may be an entire pathogen or an isolated antigen. Potent antibodies have been rapidly isolated from universally applicable, ready-made libraries of a very large size. Libraries are also custom-made for specific programs within very short time frames.

Crucell has generated several very large antibody phage display libraries built from normal donors and also from subsets of specialized B-cells. These libraries can be used immediately for selection of antibodies against any given antigen. Furthermore, Crucell can build new libraries from immunized or infected donors, which have been shown to produce the desired antibody specificities, in less than eight weeks. Crucell has developed the in-house expertise to evaluate antibodies in functional assays in a high-throughput manner. A typical antibody discovery program can thus be run in less than 9 months starting from the construction of the libraries to the delivery of a lead antibody clone.

The antibody discovery group of Crucell is internationally recognized for the rapid discovery of potent monoclonal antibodies against emerging infectious diseases. It was the first group worldwide to generate fully human mAbs, which effectively controlled SARS coronavirus infection in a relevant animal model. Recently the group discovered and published the first human monoclonal antibodies against West Nile virus. The World Health Organization (WHO) has endorsed Crucell’s rabies antibodies, which will enter clinical trials in 2006.

Crucell is currently applying its technology in the field of bacterial infections.