A comprehensive proteomics study on edible bird’s nest using new monoclonal antibody approach and application in quality control

Abstract

Edible bird’s nest (EBN) is a glue-like substance deriving from salivary secretion by specific swiftlets, and protein is considered as the main component of EBN. Accounting over 50% by weight, the exact identities of EBN proteins are still not well understood, due to difficulties of extraction, purification and identification. By using EBN proteins as antigens, 31 monoclonal antibodies specifically against the proteins were generated. The proteins of EBN were subjected to identification by shotgun proteomics. Six protein identities were revealed, including acidic mammalian chitinase (AMCase)-like, mucin 5AC-like and ovoinhibitor-like proteins. In parallel, the monoclonal antibodies were used to immunoprecipitate proteins from EBN extract, and subsequently the precipitated product(s) was identified. AMCase-like protein was most frequently precipitated by the antibodies. The existence of AMCase-like protein in EBN was further verified by: (i) recognition of chicken AMCase by our anti-EBN antibodies; and (ii) recognition of EBN AMCase-like protein by a commercial anti-AMCase antibody. The antibody was highly sensitive and selective to AMCase-like protein in EBN products, with limit of detection at 0.01 μg/mL in ELISA test. Thus, AMCase-like protein, or its antibody, could be used as a new quality control marker for EBN.