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Asphalt fume - induced immunosuppression in B6C3F1 female mice.

Diotte NM; Munson AE; Tomblyn S; Meade BJ
Toxicologist 2001 Mar; 60(1):27
Asphalt contains a complex mixture of organic molecules, including polycyclic aromatic hydrocarbons that have been reported to cause adverse health affects. In vivo (plaque forming cell assay, PFC) and in vitro (Mishell-Dunon assay, M-D) studies were conducted to investigate the immunomodulatory effects of exposure to whole asphalt fumes as well as the vapour and aerosol components of asphalt fumes in B6C3F1 mice. An asphalt fume generating system (Heritage Research Group, IN) was modified to provide conditions consistent with paving exposure. Mice treated via whole body inhalation exposure for 3.5 hrs/day for up to 10-days to asphalt fumes (35mg/m3) or the vapour component of asphalt fume (0.07 mg/m3) demonstrated an approximate 50% and 25% suppression, respectively. A >50% suppression was observed following asphalt fumes condensate exposure via the intraperitoneal (i.p., >/= 2.5 mg/kg) or intratracheal (i.t., >/= 1 mg/kg) routes. I.p. exposure to the aerosol component of asphalt fumes (5 - 40mg/kg) induced a dose responsive decrease in PFC with > 70% suppression at the high dose. Similar results were observed in vitro with exposure to both whole asphalt fume condensate and the aerosol components at concentrations as low as 0.75 mg and 0.375 mg, respectively. Allowing for distribution, in vitro exposure required higher concentrations of asphalt fume to induce immunosuppression than in vivo exposures suggesting that metabolic activation is required. Exposure to 0.75 mg of condensate as late as 4 days post immunization to sRBC in the M-D assay, induced a significant suppression in PFC response suggesting that antibody-secreting cells were targeted. Asphalt fume as well as the vapour and aerosol components of asphalt were determined to be immunosuppressive following respiratory and systemic exposure.
Asphalt-fumes; Fumes; Laboratory-animals; Animals; Animal-studies; Polycyclic-aromatic-hydrocarbons; In-vivo-studies; In-vitro-studies; Exposure-levels; Exposure-assessment; Inhalation-studies; Aerosols; Vapors
Publication Date
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NIOSH Division
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The Toxicologist. Society of Toxicology 40th Annual Meeting, March 25-29, 2001, San Francisco, California
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division