Final Activity Report Summary - PLANTIRABIES (Generation of new anti-rabies antibodies for post exposure prophylaxis and production in plants)
Infection by rabies virus causes around 40 000 to 70 000 deaths per year worldwide. More than 99 % of all human deaths occur in Africa, Asia and South America, most commonly involving children under 15 years old.
The recommended therapeutic procedure for people suspected to be infected with this virus includes the immediate administration of both vaccine and rabies' specific immunoglobulins (RIG). Prophylaxis in the form of immunoglobulins includes equine anti-rabies immunoglobulins (ERIG) or human anti-rabies immunoglobulins (HRIG); however, these reagents are expensive and in short supply, especially in developing countries. A solution that is being explored is to generate a cocktail of rabies' neutralising monoclonal antibodies to replace ERIG. If it were possible to generate enough recombinant antibodies cheaply, then this would be of enormous benefit in countries affected by rabies, particularly in Southeast Asia and Africa.
In this proposal we aimed to select new, cross-neutralising antibodies against phylogroup 1 lyssavirus strains, using recombinant antibody phage-display technology. An optimised rabies virus purification protocol was set up prior to antibody selection. A human single-chain Fv antibody phage display library was used to select specific antibodies against a rabies virus strain of British origin (EBLV2). A total of 26 scFvs clones were selected and specifically recognised the EBLV2 virus strain. Six scFv clones were further tested in vitro using virus neutralisation assays; nevertheless none was able to neutralise the virus. Although the main goal of this project, i.e. the selection of neutralising antibodies against phylogroup 1 Lyssavirus strains, was not achieved, we demonstrated that the phage display technology was a powerful approach for the selection of rabies specific antibodies. Furthermore, we described optimised protocols for both the selection of virus specifc scFvs and the use of phage particles in the virus neutralisation assays.
The recommended therapeutic procedure for people suspected to be infected with this virus includes the immediate administration of both vaccine and rabies' specific immunoglobulins (RIG). Prophylaxis in the form of immunoglobulins includes equine anti-rabies immunoglobulins (ERIG) or human anti-rabies immunoglobulins (HRIG); however, these reagents are expensive and in short supply, especially in developing countries. A solution that is being explored is to generate a cocktail of rabies' neutralising monoclonal antibodies to replace ERIG. If it were possible to generate enough recombinant antibodies cheaply, then this would be of enormous benefit in countries affected by rabies, particularly in Southeast Asia and Africa.
In this proposal we aimed to select new, cross-neutralising antibodies against phylogroup 1 lyssavirus strains, using recombinant antibody phage-display technology. An optimised rabies virus purification protocol was set up prior to antibody selection. A human single-chain Fv antibody phage display library was used to select specific antibodies against a rabies virus strain of British origin (EBLV2). A total of 26 scFvs clones were selected and specifically recognised the EBLV2 virus strain. Six scFv clones were further tested in vitro using virus neutralisation assays; nevertheless none was able to neutralise the virus. Although the main goal of this project, i.e. the selection of neutralising antibodies against phylogroup 1 Lyssavirus strains, was not achieved, we demonstrated that the phage display technology was a powerful approach for the selection of rabies specific antibodies. Furthermore, we described optimised protocols for both the selection of virus specifc scFvs and the use of phage particles in the virus neutralisation assays.