Fcabs are antibodies fragments engineered from the constant region of an antibody (Fc). In naturally occurring antibodies (such as IgGs), the antigen-binding sites are located at the variable regions (Fab).
Fcabs can be expressed as soluble proteins or they can be engineered back into a full IgG. This type of antibodies are therefore able to recognise two different antigens, one at their Fab region and a second one at the Fc region, hence the name of bispecific antibodies. This antibody fragment is part of the modular antibody technology of F-star Biotechnology Ltd.
- Wozniak-Knopp G, Bartl S, Bauer A, Mostageer M, Woisetschläger M, Antes B, Ettl K, Kainer M, Weberhofer G, Wiederkum S, Himmler G, Mudde GC, Rüker F. (2010). "Introducing antigen-binding sites in structural loops of immunoglobulin constant domains: Fc fragments with engineered HER2/neu-binding sites and antibody properties.". Protein Eng Des 23 (4): 289–297. doi:10.1093/protein/gzq005. PMID 20150180.