(c) RIKILT-Institute of Food Safety and Plant Research International,
- Codex Alimentarius Commission (2003)
Guideline for the Conduct of Food Safety Assessment of Foods derived from Recombinant-DNA Plants (CAC/GL 45-2003). Rome: Codex Alimentarius, Joint FAO/WHO Food Standards Program.
Available at: http://www.codexalimentarius.net/download/standards/10021/CXG_045e
This document recommends the following sequence comparisons between
transgenic and allergenic proteins:
8. The purpose of a sequence homology comparison is to
extent to which a newly expressed protein is similar in structure to a
known allergen. This information may suggest whether that protein has
an allergenic potential. Sequence homology searches comparing the
structure of all newly expressed proteins with all known allergens
should be done. Searches should be conducted using various algorithms
such as FASTA or BLASTP to predict overall structural similarities.
Strategies such as stepwise contiguous identical amino acid segment
searches may also be performed for identifying sequences that may
represent linear epitopes. The size of the contiguous amino acid search
should be based on a scientifically justified rationale in order to
minimize the potential for false negative or false positive results*.
Validated search and evaluation procedures should be used in order to
produce biologically meaningful results.
9. IgE cross-reactivity between the newly expressed protein and a known
allergen should be considered a possibility when there is more than 35%
identity in a segment of 80 or more amino acids (FAO/WHO 2001) or other
scientifically justified criteria. All the information resulting from
the sequence homology comparison between the newly expressed protein
and known allergens should be reported to allow a case-by-case
scientifically based evaluation.
* It is recognized that the 2001 FAO/WHO consultation suggested moving
from 8 to 6 identical amino acid segments in searches. The smaller the
peptide sequence used in the stepwise comparison, the greater the
likelihood of identifying false positives, inversely, the larger the
peptide sequence used, the greater the likelihood of false negatives,
thereby reducing the utility of the comparison.
- FAO/WHO (2001) Joint FAO/WHO Expert
Consultation on Foods Derived from Biotechnology - Allergenicity of
Genetically Modified Foods - Rome, 22 - 25 January 2001. Rome: Food and
Agriculture Organisation of the United Nations.http://www.who.int/foodsafety/publications/biotech/en/ec_jan2001.pdf
- Fiers, M.W.E.J., Gijs A Kleter, G.A., Nijland, H., Peijnenburg, A.A.C.N., Nap, J.P., van Ham R.C.H.J. (2004)
Allermatch., a webtool for the prediction of potential allergenicity according to current FAO/WHO Codex alimentarius guidelines.
BMC Bioinformatics 5:133.