To overcome these problems

To overcome these problems, variable parts of Camelid heavy-chain only antibodies (HcAbs) started to use for the development of prophylactic and therapeutic drugs against the various target. In fact, members of the camelid family have two isotypes of antibodies heterodimer and homodimer which unusual one was discovered in 1993. First one consists of heavy and light chains as well as conventional antibodies and second one contain Hc-Abs called VHH or Nb. They are fully functional in binding to specific antigens of interest even inaccessible to classical immunotherapeutic agents. They also exhibit excellent physicochemical features such as small size (12–16 kDa), high affinity to targets, solubility, extra thermal and chemical stability, low immunogenicity, high and cost-effective production (8, 9). The unique structural and functional properties of Nbs make them as efficient tool for diagnostic and therapeutic purposes. This tiny but critical part of Abs is produced using high throughput antibody phage display (APD) technology