Adjuvant activity of particulate pollutants in different mouse models

Particulate air pollutants may play a role in the increasing prevalence of respiratory allergy by acting as adjuvants for a T helper 2 (Th2) mediated immune response to common allergens. The immunomodulating capacity of well- defined polystyrene particles as well as different particles as present in our environment (diesel exhaust, carbon black, and silica particles) was in vestigated in different models. Polystyrene particles were injected intrape ritoneally or installed intratracheally, while the environmentally relevant particles were injected subcutaneously. From these studies, it becomes cle ar that all particles exert an adjuvant effect on the immune response to th e co-administered antigen. The particle core rather than attached chemical factors seems to be mainly responsible for this effect. The different parti cles, however, stimulate different types of immune responses, indicating th at physicochemical properties of particles may be of importance in steering the response towards a T helper I (Th1) or a Th2-like response. (C) 2000 E lsevier Science Ireland Ltd. All rights reserved.