Recombinant antibody technology progressed rapidly during last decade, mainly because of their human therapeutic use. The vertebrate immune system generates billions antibody molecules. Of them, camelids have been found to possess structurally different kinds of antibodies. These camelid antibodies are composed of two heavy chains similar to conventional antibodies.
Contrary to the structure found in conventional antibodies these heavy-chain antibodies lack the CH1 domain. Nanobodies are antibody-derived engineered therapeutic proteins. Nanobodies possess structural and functional properties of naturally occurring heavy chain antibodies. The nanotechnology was originally developed after the discovery that camelidae (camels & llamas) possess fully functional antibodies without light chains. These antibodies contain a single variable domain (VHH) and two constant domains (CH2 and CH3).