Single-domain antibody fragments derived from heavy-chain antibodies: a review

Single-domain antibody (sdAb) fragments derived from heavy-chain antibodies of camelids and cartilaginous fish represent a new generation of therapeutic agents and immunoreagents. Due to their unique characteristics, such as low molecular weight, high physical-chemical stability, good water solubility, and the ability to bind antigens inaccessible to conventional antibodies, they could potentially act as a substitute for conventional therapeutic drugs in the treatment of serious human diseases, and, moreover, could be broadly used in analyses and diagnostics. In this review article, an analysis of 826 publications oriented to heavy-chain antibodies and their sdAb fragments indexed in the Web of Science® database since 1993 has been carried out. Attention has predominantly been paid to papers published from 2010 to June 2012. Key publications are presented in tables and are characterised by descriptive words, abstracts and references. The presented publications have been sorted according to seven basic criteria: review articles and monographs, heavy-chain antibodies of camelids and sharks, production of sdAb fragments using recombinant technology, characteristic properties of sdAb fragments, application of sdAb fragments in therapy, application of sdAb fragments in diagnostic and immunoanalytical methods and other prospective uses of sdAb fragments. This review article should highlight the typical properties of heavy-chain antibodies and sdAb fragments which differentiate them from conventional antibodies and other available recombinant fragments, and also emphasize their extremely broad application potential, mainly in human disease therapy. At the same time it allows an easy and rapid orientation in numerous publications written on this subject, and facilitates the search for the required data.