Allergenicity of cry9c: an unresolved issue

Characterization of a Novel Insecticidal Protein Cry9Cb1 from Bacillus thuringiensis

In recent decades, there have been increasing reports of insect resistance in Bacillus thuringiensis (Bt) crops. Alternative use of Cry toxins, with high insecticidal activity and different mechanisms of action, may be an important strategy to manage this resistance. Cry9 protein, with high toxicity to the lepidopteran pests and no cross-resistance with commercial Cry1 proteins, is a valuable relevant resource. A novel insecticidal protein, MP1489, subsequently named as Cry9Cb1, with 88% amino acid sequence identity with Cry9Ca1, was identified from Bt strain SP663; it exhibited high insecticidal activity against Plutella xylostella, Ostrinia furnacalis, and Chilo suppressalis and no cross-resistance with Cry1Fa in Ostrinia furnacalis. Its minimal active fragments against Plutella xylostella and Ostrinia furnacalis were identified to be 72^T-657^V and 68^D-655^A, respectively; food-safety assessment showed no sequence homology with any known allergen and rapid degradation and inactivation by both heat and the gastrointestinal environment. Therefore, Cry9Cb1 is proposed to have a brilliant prospect as an insecticidal protein in agriculture.

Food biotechnology: is this good or bad? Implications to allergic diseases

BACKGROUND

Food biotechnology represents advancement in the traditional interspecies and intergeneric breeding methods for improving food supplies worldwide. With respect to safety, foods developed through biotechnology techniques represent one of the most extensively reviewed agricultural advancements in history.

OBJECTIVE

To review the relevant issues with respect to foods from genetically modified crops and allergenicity.

DATA SOURCES

To impart this information, the author will rely upon his experiences with investigations into food allergy and food allergens, participation in various workshops designed to determine allergenicity of novel proteins introduced into the diet, web sites, issue papers, and articles relevant to the topic.

RESULTS

Given that there are no validated methods or models to determine potential allergenicity of novel proteins, criteria have been established based upon characteristics of known food allergens. The combination of genetic and bioinformatics information available from known food allergens applied to foods developed from genetically modified crops to avoid the inadvertent introduction of allergens into foods should pose no significant allergenic concern to individuals with a genetic predisposition to food allergy. Education and sound scientific evaluation provided to the consumer should alleviate any fear of emotionalism as implied by "Frankenfoods."

CONCLUSIONS

The estimation that more than two trillion transgenic plants have been grown in 1999 and 2000 alone, with no overt documented adverse food reactions being reported, indicates that genetic modification through biotechnology will not impose immediate significant risks as food allergen sources beyond that of our daily dietary intake of foods from crop plants.