David Quist
Tracy Munthali 
Conny Tummler
Yan Liu
Kaare Nielsen
Terje Traavik

The global use and consumption of genetically modified (GM) crops in world agriculture is immense. Crop varieties expressing the cryIAb gene from B. thuringiensis (Bt) make up the single largest class of transgenic insecticidal crop plants worldwide, and are consumed as foodstuffs by millions of people every day. One maize variety, known scientifically as MON810 and commercially as ”Yieldgard” (Monsanto Corp.), is approved for human consumption in more than a dozen countries worldwide, including the US and parts of the EU. Bt crops account for at least 19% of total GM crop production, and are on the rise.

Currently, risk assessment studies of GM crops primarily utilize of bacterial versions of the transgenic proteins for safety analysis, rather than the plant version for which approval is being sought. Recent scientific evidence has documented immunogenically significant structural changes to proteins expressed under different culture or host expression systems. Likewise, product assessments of plant-made pharmaceuticals have shown increased immunogenicity in plant-made protein forms, compared to non-plant forms. These studies have been essential for avoiding potentially harmful products from entering the marketplace. Unfortunately, similar product quality or immunogenicity testing frameworks in transgenic crops are lacking. Despite a report of protein similarities between cryIAb and the known allergen vitellogenin, followup allergenicity studies of this transgenic protein have not been performed.

The aim our study is to determine whether there are any meaningful structural or functional differences between bacterially-produced transgenic cryIAb (Bt) insecticidal proteins (used in safety assessments), and the plant produced versions of the protein (which are consumed yet not directly tested for safety). The outcomes of this study will help elucidate the relevance of the current practice of using bacterial versions as surrogates for safety testing in lieu of the plant version for which commercial approval is being sought. Results will help guide future frameworks on safety testing for plant- produced proteins, including the oncoming wave of plant-made pharmaceuticals, now entering the global marketplace.