Di-(2-ethylhexyl) phthalate possesses an adjuvant effect in a subcutaneousinjection model with BALB/c mice

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America and the introduction of anthropogenic chemicals m ay explain a part of this increase. Recently, our group found that degradat ion products from several commonly used phthalate plasticizers possess adju vant activity in an animal model. Mono-2-ethylhexyl phthalate, which is the degradation product of di-(2-ethylhexyl) phthalate (DEHP), was among these substances. These findings prompted the study of the adjuvant activity of the parent compound itself. Thus, DEHP was studied in a model using ovalbum in (OA) as the model antigen. OA was injected subcutaneously in the neck re gion of BALB/cJ mice with or without DEHP. The levels of OA-specific IgE, I gG1 and IgG2a antibodies in sera were measured by ELISA. Adjuvant effect, d efined as a statistically significant increase in antibody level, was obser ved with IgG1 at a concentration of 2000 mug DEHP/ml after both one and two boosters. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.