title: Inhalation of acid coated carbon black particles impairs alveolar macrophage phagocytosis.
abstract: A flow-past nose-only inhalation system was used for the co-exposure of mice to carbon black aerosols (CBA) and sulfur dioxide (SO2) at varying relative humidities (RH). The conversion of SO2 to sulfate (SO4(-2)) on the CBA, at a fixed aerosol concentration, was dependent on RH and SO2 concentration. The effect of the aerosol-gas mixture on alveolar macrophage (AM) phagocytosis was assessed three days following exposure for 4 h. Exposure to 10 mg/m3 CBA alone at low RH (10%) and high RH (85%), to 10 ppm SO2 alone at both RH, and to the mixture at low RH had no effect on AM phagocytosis. In contrast, AM phagocytosis was significantly suppressed following co-exposure at 85% RH, the only circumstance in which significant chemisorption of the gas by the aerosol and oxidation to SO4(-2) occurred. The results suggest that fine carbon particles can be an effective vector for the delivery of toxic amounts of SO4(-2) to the periphery of the lung.
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins School of Hygiene and Public Health, Baltimore, MD 21205, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Jakab
authors.forename: R W
authors.initials: RW
authors.lastname: Clarke
authors.forename: D R
authors.initials: DR
authors.lastname: Hemenway
authors.forename: M V
authors.initials: MV
authors.lastname: Longphre
authors.forename: S R
authors.initials: SR
authors.lastname: Kleeberger
authors.forename: R
authors.initials: R
authors.lastname: Frank
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000633:toxicity; D000818:Animals; D001273:Atmosphere Exposure Chambers; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002244:Carbon / Q000008:administration & dosage / Q000633:toxicity*; D002452:Cell Count / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005260:Female; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D010587:Phagocytosis / Q000187:drug effects*; D011961:Receptors, Fc / Q000187:drug effects / Q000502:physiology; D013431:Sulfates / Q000032:analysis; D013458:Sulfur Dioxide / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D000336:Aerosols; D011961:Receptors, Fc; D013431:Sulfates; D013458:Sulfur Dioxide; D002244:Carbon