title: Suppression of rat and mouse lymphocyte function by urban air particulates (Ottawa dust) is reversed by N-acetylcysteine.
abstract: Epidemiology studies have demonstrated increased pulmonary morbidity such as allergy and infection with episodes of high particulate air pollution (size range 0.1-10 microm diameter, PM10), but the mechanism(s) for this association is not yet well defined. The present study was undertaken to evaluate the effects of EHC-93 urban particles (Ottawa dust) on immune functions of peripheral blood mononuclear cells (PBMCs) and splenocytes from male Fischer 344 rats and C57Bl/6 mice. Immune function endpoints evaluated included cell viability, lymphocyte blastogenesis stimulated by T-cell mitogen (concanavalin A, Con A) or B-cell mitogens [lipopolysaccharide (LPS) or LPS/dextran sulfate], intracellular Ca2+ concentration, interleukin 2 (IL-2) production, and expression of receptors for transferrin (TfR) and IL-2 (IL-2R). In addition, the effect of N-acetylcysteine (NAC), an antioxidant, on the toxicity of EHC-93 particles was evaluated. Total EHC-93 particles, water leachate of EHC-93, and washed EHC-93 suppressed proliferation of PBMCs and splenocytes to T- and B-cell mitogens. Treatment of splenocytes with EHC-93 particles did not alter intracellular Ca2+ concentration or mitogen-induced expression of TfR and IL-2R expression, but increased IL-2 production assayed by enzyme-linked immunosorbent assay (ELISA). In spite of an increase in IL-2 production, exogenous IL-2 when added to cultures was able to reverse the suppression of Con A-induced lymphocyte proliferation by EHC-93 particles. Furthermore, the suppressive effect of EHC-93 particles on mitogen-induced lymphocyte proliferation was completely abolished by addition of the antioxidant NAC to cultures, suggesting a possible role of oxidative factors for the toxicity of EHC-93 particles.
authors.affiliation: INRS-Institut Armand-Frappier Centre de Recherche en Sante Humaine, Université du Québec, Pointe-Claire, Canada. felix.omara@inrs-sante.uquebec.ca
authors.forename: F O
authors.initials: FO
authors.lastname: Omara
authors.forename: M
authors.initials: M
authors.lastname: Fournier
authors.forename: R
authors.initials: R
authors.lastname: Vincent
authors.forename: B R
authors.initials: BR
authors.lastname: Blakley
mesh_terms: D000111:Acetylcysteine / Q000819:agonists / Q000494:pharmacology*; D000393:Air Pollutants / Q000037:antagonists & inhibitors / Q000633:toxicity*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004391:Dust; D016166:Free Radical Scavengers / Q000819:agonists / Q000494:pharmacology*; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009864:Ontario; D051381:Rats; D011916:Rats, Inbred F344; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology
chemical_list: D000393:Air Pollutants; D004391:Dust; D016166:Free Radical Scavengers; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011990:Receptors, Transferrin; D002118:Calcium; D000111:Acetylcysteine