Adjuvant and immuno-suppressive effect of six monophthalates in a subcutaneous injection model with BALB/c mice

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America. This increase in disease prevalence may be assoc iated with environmental pollutants. The present study investigated the adj uvant and immuno-suppressive effect of a series of monophthalates which are considered to be important metabolites of commonly used phthalate plastici zers. The effects were studied in a screening model. Ovalbumin (OA), used a s the model antigen, was injected subcutaneously in the neck region of BALB /cJ mice with or without one of the test substances, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBnP), mono-n-octyl phthalate (MnOP), mono-2 -ethylhexyl phthalate (MEHP), mono-iso-nonyl phthalate (MiNP) or mono-iso-d ecyl phthalate (MiDP). The levels of OA-specific IgE, IgG1 and IgG2a in ser a were measured by ELISA. Immuno-suppressive effect, defined as a statistic ally significant reduction in IgE or IgG1 antibody production, was observed with MEHP (1000 mug/ml, IgE and IgG1), MnOP (1000 mug/ml, IgE and IgG1), M iNP (1000 mug/ml, IgE and 10 mug/ml, IgG1) and MiDP (100 mug/ml, IgE and Ig G1). Adjuvant effect, defined as a statistically significant increase in Ig E or IgG1 antibody level, occurred with MEHP (10 mug/ml, IgE), MnOP (100 mu g/ml, and 10 mug/ml, IgG1) and MiNP (100 mug/ml, IgE). No statistically sig nificant immune modulating effect was seen with MBnP and MnBP. (C) 2001 Els evier Science Ireland Ltd. All rights reserved.