In Vivo Tests for Respiratory or Oral Sensitization

As mentioned in the introduction, standard test methods for respiratory or oral sensitization have not been developed. 

In a review. Arts and Kuper (2007) have summarized the animal test methods, which have been used to detect immune-mediated respiratory disease. The tests for respiratory sensitization include dermal as well as inhalatory or topical exposure of mice, rats, or guinea pigs for induction and challenge, and may measure various endpoints to evaluate respiratory sensitization. The review concludes that standardized and validated dose-response test methods are urgently required in order to allow identification of respiratory allergens and to make it possible to recommend safe exposure levels for consumers and workers. 

With respect to oral sensitization, attempts have been made to develop animal models of food allergy, which so far has proven to be complicated. One crucial point is the route of exposure experience indicates that it may not be possible to develop an animal model, which rnirnics the human sensitization via the oral route. Exposure via the diet or in drinking water appears in rodents to be more likely to cause immunological hyporesponsiveness (i.e., tolerance) than sensitization, and therefore it may be necessary to use parenteral induction in animal testing (Dearman and Kimber 2007). 

The OECD, US-EPA, and EU have no adopted test guidelines for in vitro testing of sensitization. 

Very recently, a WHO/IPCS international workshop on skin sensitization in chemical risk assessment has taken place. The general conclusions and recommendations of the workshop have been pubhshed (WHO/IPCS 2007). These conclusions and recommendations are cited in Section 4.6.5. 

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