Variability of a mouse ear swelling test (MEST) in predicting weak and moderate contact sensitization.

An investigation was conducted at two independent laboratories for the purpose of evaluating the ability of a mouse ear swelling test (MEST), previously developed and validated by S.C. Gad. B.J. Dunn, D. W. Dobbs, C. Reilly, and R.D. Walsh (1986, Toxicol. Appl. Pharmacol. 84, 93-114), to predict contact sensitization induced by weak to moderate contact sensitizers. Twenty-six coded chemicals, 23 with weak to strong potential to induce sensitization in animals and/or humans and 3 negative controls, were investigated. Each laboratory tested 18 materials: 10 chemicals were common to both labs and 16 chemicals were divided so that 8 were unique to each of the two labs. The methods and chemicals utilized were the same as those used and reported by Gad et al. (1986) and, therefore, data generated from this investigation were compared to results from their research. Contrary to results reported by Gad and co-workers, findings from the present study suggest that this MEST is a useful model for identifying strong contact sensitizers, but is not reliable for detecting weak to moderate allergens.