State research body the Council for Scientific and Industrial Research (CSIR) has partnered with plant-made protein specialist Kentucky BioProcessing (KBP) to create a rabies antibody product by using plant systems.
CSIR Biosciences chief
researcher and project principal
investigator Dr Rachel Chikwamba explains that the rabies antibodies are used to treat people
that have been exposed to the virus. The molecules are usually obtained from a serum extracted from immunised individuals, which is then isolated and purified following specific quality and safety control measures.
But there is too little serum available, which is why the CSIR is researching the creation of a version of these molecules in a plant system that can act as a substitute for, or complement, the human molecule product.
The CSIR has obtained the genes that encode for the protein and has introduced these molecules into genetically engineered tobacco plants. She explains that the plant’s genetic machinery reads the genes and expresses
them into its leaves. The leaves are then harvested and the juices squeezed out of the leaves. The plant proteins are removed from the juice and the rest is purified to a high degree and stored as a new rabies antibody product.
“Hopefully, in the future, the antibody will be used in humans. So far, the indications in small mice models and cell cultures show that it works the same as the human serum,” she says.
The project began with funding from the Department of Science and Technology in 2005 as part of the European Union Pharma-Planta project, a consortium of 39 principal scientists from academic and industrial institutions in Europe and South Africa aiming to develop plant platforms for immunotherapeutic biomolecule production.
CSIR Biosciences research and development outcomes manager Fanie Marais says that the business plan for the antibody, which has been trademarked as RabiVir, was written in 2008 and the CSIR won the South Africa Bio Business Plan competition, which is an initiative of the technology innovation facilitator, the Innovation Fund, in partnership with Emory University, in the US, with the ultimate aim of helping to promote the creation of new, venture-capital-friendly biotechnology companies based in South Africa. The funding allowed
researchers to visit the US to view how plant graft pharmaceutical research is carried out by international companies, such as KBP.
The CSIR entered into the collaboration with KBP, as the company has modern Food and Drug Administration-approved facilities and is one of the first companies to use tobacco plants for pharmaceuticals. KBP will provide the research organisation with technology transfer and will train South African researchers in the art of purifying antibodies from plants. The CSIR will also involve KBP in the construction of a commercial plant when this is built.
He adds that the CSIR expects
that, after three years, there will
be a clinical batch that can be used for human testing and it aims
to spin out a company called GreenPharm as a separate entity
that can take the antibody through
this clinical testing phase and launch it in about six years.
“We think that this initiative is one of the most advanced in the country and we have collaborators that are leaders in the technology of purifying plant
antibodies,” says Chikwamba.
She concludes that the CSIR Biosciences unit has a pipeline of molecules, besides the rabies
antibody, focused on infectious diseases.
It also plans to expand its pipeline to reagent and diagnostic research products and has several molecules that are cur-
rently under feasibility testing.
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