(Trumble et al. 1990 and in press) show that allergens can be inadvertently changed during conventional breeding, and there is no substantial body of information on this possibility. There are some examples of assessments of endogenous allergens in transgenic plants (Burks and Fuchs 1995; Metcalfe et al. 1996a).

2.5.3 Summary

The above questions can be used to guide the review process for the potential health effects of transgenic pest-protected plants. In reviewing toxicity testing relevant to human health for currently commercialized transgenic pest-protected plant products (that is, Bt toxins and viral proteins), the committee found that,

When the active ingredient is a protein, short-term oral toxicity and potential allergenicity testing are currently appropriate, inasmuch as the testing protocols are the ones currently available. However, testing protocols, particularly for allergenicity, should be improved with additional research.

The committee recommends that

When the active ingredient of a transgenic pest-protected plant is a protein and when health effects data are required, both short term oral toxicity and potential for allergenicity should be tested. Additional categories of helath effects testing (such as for carcinogenicity) should not be required unless justified.

Additional categories of toxicity testing do not appear justified for currently commercialized products (such as products with Cry1A and 3A Bt endotoxins and viral coat proteins). However, in these cases, it important that the tests that are performed be rigorous, logical, and scientifically sound (see section 2.5.1, section 2.5.2, and section 3.1.3). Novel, or less familiar plant-pesticides (that is, in comparison to viral coat proteins and Bt toxins) may require additional toxicity testing.

In addition, given the difficulties with determining the potential allergenicity of proteins not currently in the food supply, the committee recommends that

Priority should be given to the development of improved methods for identifying potential allergens in pest-protected plants, specifically, the development of tests with human immune-system endpoints and of more reliable animal models.

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