Fine particles of widely different composition have an adjuvant effect on the production of allergen-specific antibodies

Diesel exhaust particles (DEP) are reported to increase the specific IgE re sponse to allergens, and results from our laboratory suggest that the parti cle core of DEP contribute to this adjuvant activity. The purpose of the pr esent study was to explore further the adjuvant effect of particles per se, that is particles by themselves. NIH/Ola mice were given two intraperitone al injections with ovalbumin (OVA; 10 mug) alone or OVA in combination with PSP, polytetrafluoroethylene (teflon), titanium dioxide (TiO2) or amorphou s silica particles (2.8 x 10(10)-2.8 x 10(12)). Blood samples were drawn 7 days after the last injection, and serum levels of allergen-specific and to tal IgE and IgG2a were measured. All types of particles gave increased leve ls of allergen-specific IgE and IgG2a. Similar results were obtained after intranasal or intratracheal instillation with OVA plus PSP or silica. Our r esults indicate that fine particles of widely different composition may hav e an adjuvant effect on the production of allergen-specific antibodies. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.