From Table 2, we can see that the level of histamine of the
test group was not significantly different from that of the negative
group, while that of the positive was 2-times higher than and differed
significantly fromthat of the test group (P < 0.05).
FAO/WHO has proposed the decision tree to assess the potential
allergenicity of novel gene products. If the introduced gene encodes
a known allergen, the recombinant protein may be tested for allergenicity
by the classical in vitro tests using sera. If the source of the
transgene has no history of allergenicity, alternative approaches are
required based on the structure and stability of the foreign protein.
These approaches must be critically appraised and applied on a
case-by-case basis. TheHPT protein belonged to the latter group, so
it was assessed mainly by in vitro gastrointestinal digestion and by
an animal model. At present, digestion in vitro is an accepted model
system, but good (oral) animal models to study food allergy and allergenicity
of food proteins are not (yet) available. Several strains
of rodent have been developed, but are still under discussion. At
present, most studies have been done with BN rats receiving the potential allergen via gavage without the use of adjuvant (Kimber
and Dearman 2001; Knippels and Andr´e 2005).
We adopted the 3R International Principle that proposes that
the number of test animals should not exceed 6 and that healthy
conditions should be maintained (Zheng 2005). We demonstrated
that under these conditions, the BN strains could be a good allergy
model.