Single chain antibody fragment with serine protease inhibitory property capable of neutralizing toxicity of Trimeresurus mucrosquamatus venom

Biochem Biophys Res Commun. 2015 May 1;460(2):170-6. doi: 10.1016/j.bbrc.2015.02.169. Epub 2015 Mar 10.

Abstract

Trimeresurus mucrosquamatus (TM) is one of majorities of snake envenomation with necrotic and hemorrhagic toxin in Taiwan. In this study, chickens were used as an alternative animal model for immunization with TM venom. Using phage display technology to process four rounds of panning, selected single chain variable fragments (scFv) could specifically recognize TM venom proteins, which were later identified as a group of homogeneous venom serine protease. The specific scFv antibodies showed various inhibitory effects on sheep RBC lysis induced by TM venom using an indirect hemolytic assay in vitro. In addition, the survival times of mice were extended to certain degrees when treated with these scFv antibodies individually or in a combination. To elucidate the inhibitory mechanism, we used molecular modeling to build up the serine protease structure to simulate the possible interactions with scFv antibodies. The results suggested that the CDR-loop of the scFv antibodies (3S10 or 4S1) might bind at the 99-loop of venom serine protease so as to affect substrate access due to the partial collapse of the subsite S2 and the partial movement of the subsite S4. It is hoped these chicken-derived antibodies could be applied to develop diagnostic and therapeutic agents against snakebites.

Keywords: Molecular modeling; Phage display technology; Single chain variable fragment; Trimeresurus mucrosquamatus; Venom serine protease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / immunology
  • Antibody Formation
  • Blotting, Western
  • Chickens
  • Crotalid Venoms / antagonists & inhibitors
  • Crotalid Venoms / immunology
  • Crotalid Venoms / toxicity*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Molecular Docking Simulation
  • Serine Proteinase Inhibitors / pharmacology*
  • Single-Chain Antibodies / pharmacology*
  • Trimeresurus

Substances

  • Antibodies, Neutralizing
  • Crotalid Venoms
  • Serine Proteinase Inhibitors
  • Single-Chain Antibodies
  • Trimeresurus venoms