title: The effect of size-segregated ambient particulate matter on Th1/Th2-like immune responses in mice.
abstract: BACKGROUND
  Particulate matter (PM) has been associated with increased pulmonary and cardiovascular mortality and morbidity. Additionally, PM is known to exacerbate asthma. However, whether ambient PM exposure contributes to the onset of asthma, especially in non-atopic children and adults, is less conclusive. The current study aimed to evaluate the effects of size-fractioned PM on lung immune responses in healthy BALB/c mice.
  
  
  RESULTS
  We collected PM10, PM2.5, PM1 and PM0.1 samples from October 2012 to August 2013 in the Taipei Basin. These PM samples were representative of urban traffic pollution. The samples were extracted and sonicated in phosphate-buffered saline (PBS). Female BALB/c mice were exposed to the samples via intratracheal instillation at three different doses: 1.75 mg/kg (35 μg/per mouse), 5 mg/kg (100 μg/per mouse), and 12.5 mg/kg (250 μg/per mouse). The mice were exposed on days 0 and 7, and PBS alone was used as a control. Following the exposures, the expression profiles of inflammatory cells and cytokines in bronchoalveolar lavage fluid (BALF) were assessed. Exposure to PM10 resulted in inflammatory responses, including the recruitment of neutrophils and the induction of T helper 1 (Th1) cell-related cytokine release, such as TNF-α and IFN-γ. Furthermore, an allergic immune response, including the recruitment of eosinophils and the up-regulation of T helper 2 (Th2) cell-related cytokine release, such as IL-5 and IL-13, was also observed in the BALF of mice exposed to PM10.
  
  
  CONCLUSIONS
  Our study showed that exposure to PM alone caused mixed Th1/Th2 inflammatory responses in healthy mice. These findings support the hypothesis that PM may contribute to the onset of asthma.
authors.affiliation: Division of Pulmonary Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan.|Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Kuo-Liang
authors.identifier: http://orcid.org/0000-0001-6176-9989
authors.initials: KL
authors.lastname: Huang
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Szu-Yuan
authors.initials: SY
authors.lastname: Liu
authors.affiliation: Research Center for Environmental Change, Academia Sinica, Taipei, Taiwan.
authors.forename: Charles C K
authors.initials: CC
authors.lastname: Chou
authors.affiliation: Department of Pathology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan.
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Tsun-Jen
authors.initials: TJ
authors.lastname: Cheng
mesh_terms: D000393:Air Pollutants / Q000633:toxicity; D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid; D005260:Female; D018793:Interleukin-13 / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D052638:Particulate Matter / Q000633:toxicity*; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology*; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*
chemical_list: D000393:Air Pollutants; D018793:Interleukin-13; D015848:Interleukin-5; D052638:Particulate Matter