Predictive evaluation in animals of the contact allergenic potential of medically important substances. I. Comparison of different methods of inducing and measuring cutaneous sensitization.

Groups of guinea pigs were sensitized with a 0.1% solution of dinitrochlorobenzene (DNCB) by the Draize intracutaneous method. The course of the induction process, the influence of the vehicles used and the extent to which the reactions are amenable to assessment according to objective criteria were examined. The sensitivity of the standardized Draize test was then compared with that of various other sensitization techniques, including: The intracutaneous test with adjuvant (optimization test) The maximization test according to Magnusson & Kligman (1969) The epidermal sensitization test The epidermal sensitization test with prior irritation of the contact site (by croton oil or sodium lauryl sulphate). Comparison of these methods revealed that either the additional application of adjuvant or prior irritation of the contact site augmented the degree of sensitization of DNCB just as greatly as the simultaneous use of adjuvant and prior irritation of the skin, (maximization test). The improved sensitization methods, and in particular the standardized optimization test, may prove to be of particular value for the study of so-called weak allergens.