Agriculture Reference
In-Depth Information
medium.readily.for.puriication..As.a.result,.many.pharmaceutical.proteins.includ-
ing. mAbs,. scFv,. and. their. fusion. proteins. have. been. produced. in. tobacco. or. rice-
cell-suspension.cultures.
242
.In.fact,.the. irst. plant-made.pharmaceutical. approved.
by.the.FDA.was.a.poultry.vaccine.against.Newcastle.disease.produced.in.tobacco.
suspension.cells.
243
.In.addition.to.tobacco.cells,.rice.and.carrot.cells.are.also.being.
developed.for.pharmaceutical.production..For.example,.carrot.cells.are.being.used.
by. Protalix. Biotherapeutics,. a. biotechnology. company. in. Israel,. to. produce. the.
enzyme.glucocerebrosidase.(GCD).as.an.enzyme.replacement.therapy.agent.to.treat.
the.Gaucher.disease..They.have.shown.that.GCD.produced.in.cultured.carrot.cells.
has.several.advantages.over.GCD.derived.from.CHO.cells,.including.increased.gly-
can.eficacy.and.consistency.and.longer.product.half-life.in.blood.serum.
244
Single-cell. cultures. of. algae. such. as.
chlorella
. and.
chlamydomonas
. offer. short.
generation. time,. fast. vegetative. biomass. growth,. and. require. inexpensive. cultiva-
tion.in.water.and.inorganic.nutrients.with.sunlight..The.biased.alga-speciic.genetic.
codon.usage.has. been. problematic.for.expressing.human.or.animal.genes.in.these.
algae,. but. has. been. resolved. by. using. alga-codon. optimized. synthetic. genes.
245
. It.
was.initially.proposed.that.the.algae-based.protein.expression.systems.could.be.eas-
ily.maintained.in.ponds.or.larger.water.bodies.for.large-scale.biomass.production..
However,.biosafety.and.environmental.concerns.have.limited.the.use.of.these.cul-
tures.in.controlled.simple.containers.or.more.sophisticated.low-through.transparent.
“reactors.”.The.green.alga.
Chlamydomonas reinhardtii
.has.been.a.successful.model.
alga.in.expressing.several.pharmaceutical.proteins.including.foot-and-mouth.disease.
virus.VP1-CTB.fusion.protein.and.a.scFv.for.herpes.simplex.virus.glycoprotein.D.with.
transgenes. transformed. into. either. its. nuclear. or. chloroplast. genomes.
246-247
. Other.
algae. species. such. as.
Chlorella ellipsoidea
. and.
Dunaliella salina
. have. also. been.
explored.for.PMP.production.
246,249
REGULATORY CONCERNS AND PUBLIC ACCEPTANCE
PMP.is.a.potentially.revolutionary.technology.for.providing.vast.affordable.pharmaceu-
tical.proteins.to.the.world..However,.as.other.transformative.technological.develop-
ments,.PMP.is.also.plagued.with.controversy.and.has.stimulated.signiicant.public.
debate..One.of.the.major.issues.confronting.commercial.PMP.production.is.the.pub-
lic.perception.that.the.bioproduction.of.pharmaceuticals.with.food.or.feed.crops.could.
potentially.contaminate.the.human.or.animal.food.chains..Some.in.the.agriculture.
and.food.industry.also.share.such.concerns.for.reasons.that.any.potential.contamina-
tion.could.negatively.impact.their.businesses.
250
.Many.of.these.concerns.are.caused.
by.several.contamination.incidents.that.have.special.resonance.for.the.PMP.ield.
251.
The.most.publicized.episode.was.the.one.involving.a.Texas-based.biotech.company,.
ProdiGene.Corp..In.2002,.corn.and.soybean.harvested.in.Nebraska.and.Iowa.were.
found. contaminated. with. ProdiGene's. transgenic. corn. seeds. intend. to. express. a.
transgene. of. TGEV. for. a. candidate. pig. diarrhea. vaccine.. As. a. result. of. the. con-
tamination,.more.than.12,000.tons.of.soybeans.have.to.be.destroyed,.and.ProdiGene.
was.penalized.by.the.U.S..government.with.a.ine.of.$250,000.
251
.In.addition.to.the.
potential.contamination.of.human.food.supplies,.other.concerns.among.the.general.
public.and.scientists.include.the.potential.escape.of.transgene.into.the.environment.
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