Recombinant plants provide a new approach to the production of bacterial polysaccharide for vaccines.
Bacterial polysaccharides have numerous clinical or industrial uses. Recombinant plants could offer the possibility of producing bacterial polysaccharides on a large scale and free of contaminating bacterial toxins and antigens. We investigated the feasibility of this proposal by cloning and expressing the gene for the type 3 synthase (cps3S) of Streptococcus pneumoniae in Nicotinia tabacum, using the pCambia2301 vector and Agrobacterium tumefaciens-mediated gene transfer. In planta the recombinant synthase polymerised plant-derived UDP-glucose and UDP-glucuronic acid to form type 3 polysaccharide. Expression of the cps3S gene was detected by RT-PCR and production of the pneumococcal polysaccharide was detected in tobacco leaf extracts by double immunodiffusion, Western blotting and high-voltage paper electrophoresis. Because it is used a component of anti-pneumococcal vaccines, the immunogenicity of the plant-derived type 3 polysaccharide was tested. Mice immunised with extracts from recombinant plants were protected from challenge with a lethal dose of pneumococci in a model of pneumonia and the immunised mice had significantly elevated levels of serum anti-pneumococcal polysaccharide antibodies. This study provides the proof of the principle that bacterial polysaccharide can be successfully synthesised in plants and that these recombinant polysaccharides could be used as vaccines to protect against life-threatening infections.
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, Leicestershire, United Kingdom.
Claire M
CM
Smith
The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom.
Stephen C
SC
Fry
School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom.
Kevin C
KC
Gough
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, Leicestershire, United Kingdom.
Alexandra J F
AJ
Patel
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, Leicestershire, United Kingdom.
Sarah
S
Glenn
Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
Marie
M
Goldrick
Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
Ian S
IS
Roberts
Department of Biology, University of Leicester, Leicester, Leicestershire, United Kingdom.
Garry C
GC
Whitelam
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, Leicestershire, United Kingdom.
Peter W
PW
Andrew
D016960:Agrobacterium tumefaciens / Q000235:genetics; D000818:Animals; D016667:Bacterial Capsules / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018014:Gene Transfer Techniques; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000254:growth & development; D011008:Pneumococcal Infections / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000276:immunology*; D014026:Nicotiana / Q000737:chemistry; D014611:Vaccination
D022242:Pneumococcal Vaccines; C413446:type 3 capsular polysaccharide, Streptococcus pneumoniae; D016695:Glycosyltransferases; C413445:type 3 capsular polysaccharide synthase