shark antibody

Sharks, and other members in Chondrichthyes, are currently recognized as the most evolutionarily ancient animals that rely on antibodies as part of their adaptive immune system. Interestingly, apart from the expected IgM and IgW, cartilaginous fishes also produce a type of ancestral antibody referred to immunoglobulin new antigen receptor (IgNAR). IgNAR is quite unconventional antibody composed of only a homodimeric heavy chain which contains one variable and five constant domains for each chain (Fig. 1). Owe to the distinct structure between shark and human antibody domains, the extremely high stability of IgNAR has been presented. In addition, VNAR is around 10 times smaller than standard antibodies and able to continue to function and exist within very extreme conditions. These properties allow IgNAR to play a potential role in pharmaceutical application. They can easily get into certain spots that regular size antibodies cannot, such as small gaps and nooks in cancer cells. Moreover, the variable domain of IgNAR can also be developed as single domain antibodies.