An empirical approach towards the efficient and optimal production of influenza-neutralizing ovine polyclonal antibodies demonstrates that the novel adjuvant CoVaccine HT™ is functionally superior to Freund's adjuvant

PLoS One. 2013 Jul 23;8(7):e68895. doi: 10.1371/journal.pone.0068895. Print 2013.

Abstract

Passive immunotherapies utilising polyclonal antibodies could have a valuable role in preventing and treating infectious diseases such as influenza, particularly in pandemic situations but also in immunocompromised populations such as the elderly, the chronically immunosuppressed, pregnant women, infants and those with chronic diseases. The aim of this study was to optimise current methods used to generate ovine polyclonal antibodies. Polyclonal antibodies to baculovirus-expressed recombinant influenza haemagglutinin from A/Puerto Rico/8/1934 H1N1 (PR8) were elicited in sheep using various immunisation regimens designed to investigate the priming immunisation route, adjuvant formulation, sheep age, and antigen dose, and to empirically ascertain which combination maximised antibody output. The novel adjuvant CoVaccine HT™ was compared to Freund's adjuvant which is currently the adjuvant of choice for commercial production of ovine polyclonal Fab therapies. CoVaccine HT™ induced significantly higher titres of functional ovine anti-haemagglutinin IgG than Freund's adjuvant but with fewer side effects, including reduced site reactions. Polyclonal hyperimmune sheep sera effectively neutralised influenza virus in vitro and, when given before or after influenza virus challenge, prevented the death of infected mice. Neither the age of the sheep nor the route of antigen administration appeared to influence antibody titre. Moreover, reducing the administrated dose of haemagglutinin antigen minimally affected antibody titre. Together, these results suggest a cost effective way of producing high and sustained yields of functional ovine polyclonal antibodies specifically for the prevention and treatment of globally significant diseases.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic*
  • Aging / immunology
  • Animals
  • Antibodies, Neutralizing / biosynthesis*
  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / biosynthesis*
  • Antibodies, Viral / immunology
  • Dose-Response Relationship, Immunologic
  • Female
  • Freund's Adjuvant / immunology*
  • Hemagglutinin Glycoproteins, Influenza Virus / immunology
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / immunology*
  • Injections, Intraperitoneal
  • Injections, Subcutaneous
  • Mice
  • Mice, Inbred BALB C
  • Orthomyxoviridae Infections / prevention & control
  • Sheep
  • Vaccines, Synthetic / administration & dosage
  • Vaccines, Synthetic / immunology

Substances

  • Adjuvants, Immunologic
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Hemagglutinin Glycoproteins, Influenza Virus
  • Influenza Vaccines
  • Vaccines, Synthetic
  • Freund's Adjuvant

Grant support

This project was supported in part by funding from the ‘Researchers-in-Business’ scheme (Enterprise Connect, Aust Fed Gov) (to JDH and BTG Australasia Pty Ltd) and the University of South Australia (Div Health Sciences) (to JDH). We also acknowledge the substantive technical, research administrative and material support of BTG Australasia Pty Ltd (Rosedale, South Australia). Accordingly BTG Australasia Pty Ltd (Rosedale, South Australia) had some role in study design and data collection but no role in the analysis, decision to publish, or preparation of the manuscript.