Lack of detectable allergenicity of transgenic maize and soya samples
Rita Batista, BSc, Baltazar Nunes, MSc, Manuela Carmo, Carlos Cardoso, PharmD, Helena Sao Jose, Antonio Bugalho de Almeida, MD, PhD, Alda Manique, MD, Leonor Bento, MD, PhD, Candido Pinto Ricardo, PhD, and Maria Margarida Oliveira, PhD, Lisboa, Oeiras, and Alge´s, Portugal
Journal of Allergy and Clinical Immunology,  August 2005,  116: 403-410

Background: The safety issues regarding foods derived from genetically modified (GM) plants are central to their
acceptance into the food supply. The potential allergenicity of proteins newly introduced in GM foods is a major safety concern.

Objective: We sought to monitor, in potentially sensitive human populations, the allergenicity effects of 5 GM
materials obtained from sources with no allergenic potential and already under commercialization in the European Union.

Methods: We have performed skin prick tests with protein extracts prepared from transgenic maize (MON810, Bt11, T25, Bt176) and soya (Roundup Ready) samples and from nontransgenic control samples in 2 sensitive groups: children with food and inhalant allergy and individuals with asthmarhinitis. We have also tested IgE immunoblot reactivity of sera from patients with food allergy to soya (Roundup Ready) and maize (MON810, Bt11, Bt176) samples, as well as to the pure transgenic proteins (CryIA[b] and CP4 5-enolpyruvylshikimate-3-phosphate synthase).

Results: None of the individuals undergoing tests reacted differentially to the transgenic and nontransgenic samples under study. None of the volunteers tested presented detectable IgE antibodies against pure transgenic proteins. Conclusion: The transgenic products under testing seem to be safe in terms of allergenic potential. We propose postmarket testing as an important screening strategy for putative allergic sensitization to proteins introduced in transgenic plants.

(J Allergy Clin Immunol 2005;116:403-10.)

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Related news item from Reading Scientific Services Limited (RSSL)

The potential allergenicity of proteins introduced into genetically modified organisms is a major safety concern.  Therefore Rita Batista, of the Instituto de Tecnologia Quimica e Biologica, and a team of co-authors from various organisations in Lisbon, Portugal examined the allergenic potential of five genetically modified materials, in a sensitive human population.

The materials tested contained one of the following types of GM maize: Bt11, Bt176, T25, MON810 or Roundup Ready (RR) soya. These GMOs have all received approval for commercialisation within the European Union.  It is particularly noted by the authors that the transgenes in the maize and soya were obtained from sources with no allergenic history.  Also, because IgE-mediated allergic reactions require prior sensitisation, the 106 individuals recruited for the study were questioned as to their consumption of soya- and maize-derived food products prior to the start of the study.  The study population included people aged 1- 41 years, with an average age of 12.4 years (48 male and 58 female subjects).

Skin prick tests with protein extracts from the GM maize and soya were carried out on the subjects. Non-transgenic controls were also tested in two extra sensitive groups: children with food and inhalant allergies and individuals with asthma-rhinitis. Sera from patients with food allergy to soya (RR)  and maize (MON810, Br11, Bt176) as well as to the pure transgenic proteins Cry1A(b) and CP4 5-enolpyruvylshikimate-3-phosphate synthase, were all tested for IgE immunoblot reactivity.  The results showed that none of the individuals undergoing tests reacted differentially to the transgenic and nontransgenic samples under study. Nor did any of the subjects tested present detectable IgE antibodies against pure transgenic proteins. On this basis, the authors concluded that GM maize and soya used in the current research appeared to be safe in terms of allergenic potential. However, they do think that the work should be extended to much large study populations and to groups from other countries.  They also suggested that specific IgE postmarket surveillance of transgenic foods should form an important screening strategy for putative allergic sensitization to proteins introduced in transgenic plants.  (Journal of Allergy and Clinical Immunology,  August 2005,  116: 403-410, full text free).

RSSL's Molecular Biology Laboratory uses multiple primer sets to enable the detection of all GM soya, maize and rapeseed varieties with turnaround times as short as two days. Real-Time quantitative PCR testing using the most robust and accurate methods available have a detection limit of 0.1% of extracted DNA.