RESEARCH ARTICLE


Cross-Reactive Anti-Avian H5N1 Influenza Neutralizing Antibodies in a Normal ‘Exposure-Naïve’ Australian Blood Donor Population



Garry W. Lynch*, 1, 2, Paul W. Selleck3, Anna-Maree Axell3, Teena Downton1, Natalie M. Kapitza1, Ingrid Boehm2, Wayne Dyer1, 2, Ying-Fan Yvonne Wang1, Sacha Stelzer-Braid4, William Rawlinson4, John S. Sullivan1, 2
1 The Transfusion Immunobiology and Biosafety Group, Transfusion Medicine and Immunogenetics Research, The University of Sydney, Camperdown, Sydney, Australia
2 Research & Business Development, The Australian Red Cross Blood Service, 153 Clarence St, Sydney, NSW 2000, Australia
3 The Australian Animal Health Laboratories, CSIRO, Geelong, Victoria, Australia
4 Virology Division, Department of Microbiology, South Eastern Area Laboratory Service, Prince of Wales Hospital, Randwick, NSW 2031, Australia


© 2008 Lynch et al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at The Transfusion Immunobiology and Biosafety Group, Level 8 R&BD Laboratories, The Australian Red Cross Blood Service, 153 Clarence St Sydney, NSW 2000, Australia; Tel: 61-2-9519 8151; E-mail: garry_lynch@optusnet.com.au


Abstract

It is necessary to understand whether some humans possess natural humoral-immune protection for avian- H5N1 influenza. To broadly assess an exposure naïve cohort we have examined intravenous immunoglobulins (IVIGs) isolated from pools of many thousands of normal Australian blood donations. In studies of the anti-H5N1 antibody potential of these highly purified IVIG therapeutics and of individual donor sera we have identified antibodies that bind to both H5N1 surface envelope and internal viral proteins and neutralize in vitro MDCK and Vero cell infections by highly pathogenic avian influenza clade I and II and human-derived H5N1 isolates. As this reactivity is removed by adsorption with purified H3N2 and H1N1 strains, anti-H5N1 cross-reacting hetero-typic antibodies are implicated. These findings support that some individuals do contain low levels of specific and neutralizing anti-H5N1 antibodies. The protective relevance of thisin vivo remains yet to be determined.

Keywords: Avian H5N1 Influenza, Human Anti-Viral Antibodies, Infection Neutralization, Virus, IVIG.