Inhibition of the Myotoxicity Induced by Bothrops jararacussu Venom and Isolated Phospholipases A2 by Specific Camelid Single-Domain Antibody Fragments

PLoS One. 2016 Mar 30;11(3):e0151363. doi: 10.1371/journal.pone.0151363. eCollection 2016.

Abstract

Antivenoms, produced using animal hyperimmune plasma, remains the standard therapy for snakebites. Although effective against systemic damages, conventional antivenoms have limited efficacy against local tissue damage. Additionally, the hypersensitivity reactions, often elicited by antivenoms, the high costs for animal maintenance, the difficulty of producing homogeneous lots, and the instability of biological products instigate the search for innovative products for antivenom therapy. In this study, camelid antibody fragments (VHH) with specificity to Bothropstoxin I and II (BthTX-I and BthTX-II), two myotoxic phospholipases from Bothrops jararacussu venom, were selected from an immune VHH phage display library. After biopanning, 28 and 6 clones recognized BthTX-I and BthTX-II by ELISA, respectively. Complementarity determining regions (CDRs) and immunoglobulin frameworks (FRs) of 13 VHH-deduced amino acid sequences were identified, as well as the camelid hallmark amino acid substitutions in FR2. Three VHH clones (KF498607, KF498608, and KC329718) were capable of recognizing BthTX-I by Western blot and showed affinity constants in the nanomolar range against both toxins. VHHs inhibited the BthTX-II phospholipase A2 activity, and when tested for cross-reactivity, presented specificity to the Bothrops genus in ELISA. Furthermore, two clones (KC329718 and KF498607) neutralized the myotoxic effects induced by B. jararacussu venom, BthTX-I, BthTX-II, and by a myotoxin from Bothrops brazili venom (MTX-I) in mice. Molecular docking revealed that VHH CDRs are expected to bind the C-terminal of both toxins, essential for myotoxic activity, and to epitopes in the BthTX-II enzymatic cleft. Identified VHHs could be a biotechnological tool to improve the treatment for snake envenomation, an important and neglected world public health problem.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antivenins* / chemistry
  • Antivenins* / genetics
  • Antivenins* / immunology
  • Bothrops*
  • Camelids, New World / genetics
  • Camelids, New World / immunology
  • Crotalid Venoms* / chemistry
  • Crotalid Venoms* / immunology
  • Crotalid Venoms* / toxicity
  • Group II Phospholipases A2* / chemistry
  • Group II Phospholipases A2* / immunology
  • Group II Phospholipases A2* / toxicity
  • Male
  • Mice
  • Molecular Docking Simulation*
  • Single-Chain Antibodies* / chemistry
  • Single-Chain Antibodies* / genetics
  • Single-Chain Antibodies* / immunology

Substances

  • Antivenins
  • Crotalid Venoms
  • Single-Chain Antibodies
  • bothropstoxin
  • Group II Phospholipases A2
  • bothropstoxin II

Grants and funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) -www.cnpq.br/RGS—Grant Number: 477760/2012-0, CFCF- Grant Number: 459046/2014-4, CFCF- Programa Primeiros Projetos Secretaria de Estado de Planejamento de> Rondônia—SEPLAN/CNPq, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Financiadora de Estudos e Projetos (FINEP), Rede de Biodiversidade e Biotecnologia da Amazônia Legal (BIONORTE/CNPq/MCT) and Fundação de Amparo ao Desenvolvimento das Ações Científicas e Tecnológicas e à Pesquisa de Rondônia (FAPERO). Nidiane D. R. Prado, student of Postgraduate Program in Experimental Biology, was supported by a fellowship of CNPq. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.