Genetically Modified
Soybeans: Equal Allergenicity
as their Wild Type
Counterparts?
Katie Van Den Einde
November 24, 2009
Advisor: Dr. Chastain
Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Importance

GM foods:
◦
◦
◦
◦
◦
◦
◦
◦
Soybeans
Corn
Tomatoes
Rice
Canola
Potatoes
Sugar beets
Sugar cane
Modifications
Herbicide resistance
 Insect resistance
 Disease resistance
 Addition of proteins/vitamins


2003 – 84% of US soybean acreage was
glyphosate tolerant (Roundup® ready)
Basics of Genetic Modification

Procedures
◦ 1. Plasmid insertion
◦ 2. Gene “guns”
◦ 3. Protoplasts
Allergies
Majority of allergic reactions are
immunoglobulin E (IgE) mediated.
 IgE allergies affect about 1-2% of adults
 2-8% of children

Symptoms:
Itchy, watery eyes
 Rash
 Congestion
 Itchiness
 Difficulty breathing
 Anaphylactic shock (Can be life
threatening)

Basics of allergic reactions
1-Allergen
 2-IgE antibodies
 3-Mast cells
 4-Histamine release

Anti-Histamines
GM Controversy





Ethics
Gene flow
Resistance
Harm to other organisms
Allergens???
Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Paper 1:

Identification of a Brazil-nut allergen in
transgenic soybeans
◦ New England Journal of Medicine 1996
Purpose:

To assess ability of proteins from
1)soybeans (Glycine max)
 2)transgenic soybeans
 3)Brazil nuts (Bertholletia excelsa)
 4)purified 2S albumin

to bind to IgE serum
Methods:



Radio allergosorbent test (RAST) – 4
serums
Sodium dodecyl sulfate-polyacrylamide-gel
electrophoresis (SDS-PAGE) – 9 serums
Skin Prick Tests
RAST basics
Results: RAST
More inhibition
of IgE binding =
more allergic.
Triangles= WT
Squares= GM soybean
Circles= Brazil nut
Results: SDS-PAGE
Total Proteins
IgE binding
IgE binding
Results: Skin-Prick Test
Main Points:

GM soybean protein successfully
competed with Brazil nut protein.

IgE from 8/9 allergic to Brazil nut bound
to introduced 2S albumin in GM
soybeans.
Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Paper 2

Lack of detectable allergenicity of
transgenic maize and soya samples
Journal of Allergy and Clinical Immunology 2005
Purpose:

Monitor 5 GM products whose
transgenes came from sources with no
allergenic history
Methods:

Food Survey
◦ Previous exposure?

Skin Prick Tests
◦ 27 kids with food allergies
◦ 50 patients with asthma rhinitis

SDS-PAGE
Flour products tested
Food survey results
Western Blot
Testing Lab Supply
SDS PAGE
Western Blot
SDS PAGE
Western Blot
Skin prick and IgE results
Main Point:

No detectable difference in IgE reactivity
between wild type and GM soybeans or
corn.
Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Paper 3

A comparative study of the allergenic
potency of wild-type and glyphosatetolerant gene-modified soybean cultivars
◦ Acta pathologica, microbiologica et immunologica Scandinavica
2003
Purpose:

To compare allergenicity of 8 wild type
and 10 GM soybeans varieties (all for CP4
EPSPS)
Methods:
RAST (serum from 10 patients)
 SDS-PAGE
 Histamine Release test
 Skin prick tests

RAST results
More inhibition
of labeled IgE
binding =
more original
serum bound first.
RAST results
Concentration of extract
needed for 50% inhibition
of IgE binding (variety #12)
Histamine Release results
Histamine
Release
(0=negative,
6=lots)
Skin Prick Test
Notice lack of any major differences – no where to point an arrow!
Histamine Release for patient I
Pretty similar!
Main Points:
Difference between patients’ response,
but no statistical difference between WT
and TG soybeans.
 Addition of CP4 EPSPS gene ≠ higher
allergenicity

Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Paper 4

Genetic modification removes an
immunodominant allergen from soybean
◦ Plant Physiology 2003
Purpose:

To silence the Gly m Bd 30K (P34) gene
transgenically
P34
A major soybean allergen
 More than 65% of soy-sensitive patients
react only to the P34 protein
 Less than 1% of total protein
 Pigs, calves and salmon also allergic

Methods:
Created a P34 silencing vector (plasmid
pKS73)
 Grew these into homozyous strains
 Used SDS-PAGE for presence of P34
protein

Results
Soybean Protein “Map”
Protein Analysis
Missing P34
proteins and
intermediates
Wild type
P34 Silenced
Main Points:

TG and WT were indistinguishable in size,
shape, protein and oil content

P34 gene silencing was successful
Overview
Introduction: GM foods, allergies,
controversy
 Paper 1
 Paper 2
 Paper 3
 Paper 4
 Current regulations
 Conclusions

Who’s in charge?
Coordinated Framework for the Regulation of
Biotechnology - 1986
 3 regulatory bodies
of genetically modified foods:

(Animal and Plant Health Inspection Service)
Considerations:
Effect on environment (animals, insects…)
 Transferable to wild type
 Digestive stability
 Toxicity
 “Weediness”

FDA
Food additives
 Manufacturers responsible for checking
 Voluntary consultation process - but all
on U.S. market have undergone

Conclusions
Allergens can be added
 Mostly, there is no difference
 Can also remove allergens
 Continue studies
 Continue monitoring

Additional Works Consulted

USDA Website. “Biotechnology FAQs.” Accessed 11/21/2009.
http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?contentidonly=true&navi
d=AGRICULTURE&contentid=BiotechnologyFAQs.xml

Singer, S., Raven, D., Johnson G., Losos, J. 2005. Biology 7th Edition. McGraw Hill.
New York, NY.
Picture References

http://agriculture.sc.gov/UserFiles/Image/soybeans7.jpg

statistihttp://tharwacommunity.typepad.com/tharwa_review/images/2008/03/12/gm_foods.jpg

http://www.mun.ca/biology/desmid/brian/BIOL2060/BIOL2060-20/2032.jpg

http://repairstemcell.files.wordpress.com/2009/03/genetically-modified-food-fda.jpg

http://animalid.aphis.usda.gov/nais/wp_images/extension/high_res/usda-logo.jpg

http://blogs.venturacountystar.com/motorhead/epa.jpg

http://www.marlerblog.com/uploads/image/fda-logo.jpg

http://web.chemistry.gatech.edu/~williams/bCourse_Information/4581/techniques/gel_elect/gel.jpg

http://www.life.umd.edu/classroom/bsci423/song

http://media.photobucket.com/image/Ige%20allergy/belldandy_84/Allergies.jpg/F03-44.jpg

http://api.ning.com/files/f7sw9nvb2lvWKi0Z-603fV67e5PN0

http://www.flourallergy.com/images/allergy-test.jpg
Y5iFz4Ef69JQNJKYzZ5lyynC5e9rpsiR7KJHFqW*CGRvzuPN6AianENPQ159UhHB680/pha0155l.jpg

http://www.worldcommunitycookbook.org/season/guide/photos/corn.jpg

http://e-internetbusiness.com/wp-content/uploads/2009/06/benadryl.png
http://www.ars.usda.gov/is/graphics/photos/sep02/k9975-3i.jpg

http://intmedweb.wfubmc.edu/grand_rounds/1999/Image15.jpg
Questions??