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.
This research successfully constructed the HPT protein expression
system in E. coli and evaluated the potential allergenicity
of the recombinant protein. In vitro digestions in SGF and animal
tests indicated that the HTP protein has likely a low allergenic potential.
Further trials still need to be done, for the safety assessment
system has its shortcomings (Astwood 1996; Cockbrun 2002; Hileman
2002; Fu and others 2002). And methods still need to be developed
for more comprehensive and exact evaluation of such introduced
new protein by biotechnology
From Table 2, we can see that the level of histamine of thetest group was not significantly different from that of the negativegroup, while that of the positive was 2-times higher than and differedsignificantly fromthat of the test group (P < 0.05).FAO/WHO has proposed the decision tree to assess the potentialallergenicity of novel gene products. If the introduced gene encodesa known allergen, the recombinant protein may be tested for allergenicityby the classical in vitro tests using sera. If the source of thetransgene has no history of allergenicity, alternative approaches arerequired based on the structure and stability of the foreign protein.These approaches must be critically appraised and applied on acase-by-case basis. TheHPT protein belonged to the latter group, soit was assessed mainly by in vitro gastrointestinal digestion and byan animal model. At present, digestion in vitro is an accepted modelsystem, but good (oral) animal models to study food allergy and allergenicityof food proteins are not (yet) available. Several strainsof rodent have been developed, but are still under discussion. Atpresent, most studies have been done with BN rats receiving the potential allergen via gavage without the use of adjuvant (Kimberand Dearman 2001; Knippels and Andr´e 2005).We adopted the 3R International Principle that proposes thatthe number of test animals should not exceed 6 and that healthyconditions should be maintained (Zheng 2005). We demonstratedthat under these conditions, the BN strains could be a good allergymodel.This research successfully constructed the HPT protein expressionsystem in E. coli and evaluated the potential allergenicityof the recombinant protein. In vitro digestions in SGF and animaltests indicated that the HTP protein has likely a low allergenic potential.Further trials still need to be done, for the safety assessmentsystem has its shortcomings (Astwood 1996; Cockbrun 2002; Hileman2002; Fu and others 2002). And methods still need to be developedfor more comprehensive and exact evaluation of such introducednew protein by biotechnology
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