ABSTRACT
Animal models have been used for years to study contact hypersensitivity.1-5 These studies have been important because they have defined the mechanisms of this type of allergic reaction. Furthermore, comparative studies of the skin immune system of rodents and humans confirmed that there is a remarkable similarity between these species. Because of these similarities, rodent models of contact hypersensitivity are widely used as attempts to predict contact allergens in humans.6-9 In an attempt to eliminate animal testing or a reliance on tissues derived from animals or the direct study of human volunteers, there is a strong impetus to develop in vitro models of allergic contact hypersensitivity. Such an in vitro model would replace human and/or animal predictive testing. The characteristics of an idealized version of such an in vitro test would include sensitivity, specificity, reproducibility, simplicity, and economy. Advances in the understanding of contact hypersensitivity have made it apparent that the immunobiology of this type of allergy is complex, and that the development of such an idealized in vitro alternative test would be a challenging task. Intuitively, the ideal in vitro predictive test(s) should examine the multiple aspects of the immunobiology of contact hypersensitivity. Presumably, risk assessment of allergen icity in humans will be based on the evaluation of multiple endpoints of the critical pathway(s) of contact dermatitis. Fortunately, advances in the areas of biotechnology and cellular and molecular immunology will facilitate the development of in vitro screening tests for contact
allergens. The application of such advances to the study of contact hypersensitivity will undoubt edly lead to better understanding of this allergy and possibly to an in vitro alternative test that is based on multiple endpoints that are developed based on a deep understanding of the critical “control points” of contact hypersensitivity.
