Lecture 38 Plantibodies
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Transcript of Lecture 38 Plantibodies
Lecture 38Lecture 38PlantibodiesPlantibodies
ANTIBODIES PRODUCED FROM PLANTS
• Functional antibodies can be produced from plants
• Targeted to intercellular space, chloroplast, seeds and tubers
• Benefit for topical immunotherapy
• Can be produced from plants in large quantities
Contd...
• Plantibodies provides increased stability
e.g: Secretory Ig A
• Plants can assemble complex secretory antibodies
e.g: Construction of tobacco plants expressing 4 transgenes
• Quadruple transgenics efficiently assembled secretory immunoglobulins
(Smith & Glick, 2000)
Anti-rabies virus mAbAnti-rabies virus mAb
After exposure treated with AbAfter exposure treated with Ab
Used to be made in horsesUsed to be made in horses
First mAb made in transgenic plantsFirst mAb made in transgenic plants
4 genes – 2 H, 2 L4 genes – 2 H, 2 L
Transgenic plant for each one and Transgenic plant for each one and crossing plantscrossing plants
Later used single binary vector with two Later used single binary vector with two promoters promoters
Full-size monoclonal antibodies recently produced Full-size monoclonal antibodies recently produced in transgenic plantsin transgenic plants
Abs expressed in transgenic Abs expressed in transgenic plantsplants
Variable Light chain
Variable Heavy chain
Recombinant hinge region
Constant domains
Functional AbsFunctional Abs
Need to be properly folded and assembledNeed to be properly folded and assembledNeed disulfide bond formation and glycosylationNeed disulfide bond formation and glycosylationDown stream processing:Down stream processing:
Purification of Ab mostly with Protein A or Purification of Ab mostly with Protein A or GG
Glycosylation is different in plantsGlycosylation is different in plantsβ β 1,2 Xylose and 1,2 Xylose and α α 1,3 fucose1,3 fucose
Retain in ER, only mannose is attachedRetain in ER, only mannose is attached–Shorter half-life of Ab Shorter half-life of Ab
Glycosylation of AbGlycosylation of Ab
Full-size AbLarge single-chain Ab Camelid heavy-chain Ab
Minibodies and Fab fragments don’t get glycosylated
Glycosylation in GolgiGlycosylation in Golgi
Antibodies: a compelling success storyAntibodies: a compelling success story
high specificity: in vitro and in vivo diagnostics
low toxicity: therapeutic applications
high drug approval rates (24 approved mAbs)
major products in biotechnology (~240 in clinical
trials)
inherently stable human proteins
injectable, topical and oral applications
applicable for chronic conditions
potential long-lasting benefits
Production Costs for AntibodiesProduction Costs for AntibodiesProduction costs cost in $ / gram
hybridomas 1000
transgenic animals 100
transgenic plants 10
Source: Daniell et al. (2001) TIPS 6, 219-226
E. coli & yeast Tr. animals andanimal cells
Transgenicplants
Comparison of Mammalian and Plant-produced Comparison of Mammalian and Plant-produced AntibodiesAntibodies
peptide sequence: identicalpeptide sequence: identical
correct cleavage of Ig-derived signal peptides correct cleavage of Ig-derived signal peptides
kinetics & affinity: identical kinetics & affinity: identical
stability in seeds > 30 monthsstability in seeds > 30 months
antibody types: plant system more versatile (sIgA)antibody types: plant system more versatile (sIgA)
post-translational processing: differentpost-translational processing: different
core glycan identical, terminal sugar different plus xylose & fucosecore glycan identical, terminal sugar different plus xylose & fucose
antigenicity & clearance: apparently identical (shorter half-life)antigenicity & clearance: apparently identical (shorter half-life)