AIRBORNE HOUSE-DUST ELICITS A LOCAL LYMPH-NODE REACTION AND HAS AN ADJUVANT EFFECT ON SPECIFIC IGE PRODUCTION IN THE MOUSE

Indoor suspended particulate matter (SPM) consists of many different t ypes of particles, the vast majority of which are less than 2.5 mu m i n diameter. An important question is how these particles, being inhala ble, contribute to asthma and respiratory symptoms. One possibility is that these particles have an adjuvant effect on the immune response a nd increase the IgE production, or cause a non-specific irritation in the airways, contributing to bronchial hyper-responsiveness. In this s tudy, the adjuvant activity of indoor SPM on the response to the model allergen ovalbumin (OA) in BALB/c mice was investigated, using the po pliteal lymph node (PLN) assay. The adjuvant activity on the local lym ph node response was determined by measuring the PLN weight, cell numb ers and cell proliferation, and the adjuvant activity on the IgE produ ction by measuring the levels of serum IgE specific to OA. SPM was fou nd to give a significant PLN response, both when injected alone and to gether with OA. SPM was also found to enhance the production of specif ic IEE to OA when injected together with OA, after reinjection with OA , compared with immunisation with OA alone. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.