A reliable rat model of the delayed hypersensitivity skin test response.

A model of the delayed type hypersensitivity response (DTH) has been developed in Sprague-Dawley rats. The sensitizing and skin test antigen is keyhole limpet hemocyanin (KLH). This antigen produces 99% sensitization and the response is maintained in 98% of the animals for up to 3 months. In four animals the DTH response was maintained greater than 1 year. The response can be abrogated with protein deprivation and restored with refeeding. The skin test method of DTH assessment correlates with an alternate technique of radiolabeled cell accumulation in the ear (r = 0.95, P less than 0.001). This model should prove useful in evaluating the role of the DTH response in measuring host resistance to infection.