IgE adjuvant effect caused by particles - immediate and delayed effects

Diesel exhaust particles are reported to increase the specific IEE response to ovalbumin (OVA) and pollen. Evidence has been provided that the particl e core contributes to this adjuvant activity. The purpose of our study was to investigate the effect of well-defined simple particles, polystyrene par ticles (PSP), on the production of allergen-specific IgE in a mouse model. The IgE adjuvant effect of PSP was investigated in experiments using intran asal (i.n.) instillation, intratracheal (i.t.) instillation or intraperiton eal (i.p.) injection. Delayed and cumulative adjuvant effects were investig ated by giving mice i.p. injections with PSP 1-3 days, or on 4 consecutive days before OVA, respectively. The levels of allergen-specific and total IE E were measured. Irrespectively of immunisation route and protocol, OVA in combination with PSP elicited increased levels of both allergen-specific an d total IgE when compared with OVA alone. Therefore, in the experimental mo del, particles were found to augment the specific IgE response to an allerg en even when the allergen was introduced several days after the particles. These findings imply that individuals exposed to particulate ail pollution at one point of time may develop an increased reaction towards allergens in haled later that day or even several days after the particle exposure. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.