Alterations in Immune Function and CYP450 Activity in Adult Male Deer Mice (Peromyscus maniculatus) Following Exposure to Benzo[a]pyrene, Pyrene, or Chrysene

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are among the most common classes of chemical contaminants found at hazardous waste sites. Deer mice (Peromyscus maniculatus) exhibit a wide geographic distribution throughout North America and have been suggested as a terrestrial biomonitoring species to facilitate comparisons between superfund sites. Chemicals tested were benzo[a]pyrene (BaP; CAS number 50-32-8), pyrene (Pyr; CAS number 129-00-0), and chrysene (Chr; CAS number 218-01-9). Adult male deer mice were exposed via intraperitoneal (ip) injection every other day for 11 d to the PAHs (0.3, 1, 3, 10, or 30 mg/kg) or a corn oil carrier control. Both BaP and Chr suppressed the plaque-forming cell (PFC) response at all treatment levels. Pyr exposure (1–30 mg/kg) also resulted in suppression of this response. Macrophage pinocytosis was suppressed only by Chr (3, 10, and 30 mg/kg). Concanavalin A-induced proliferation was stimulated by BaP at all dose levels, by Pyr at 1–30 mg/kg, and by Chr at 30 mg/kg. Chr did not affect pokeweed mitogen (PWM)-induced proliferation; however, BaP (1–30 mg/kg) and Pyr (0.3–30 mg/kg) produced stimulation of this response as compared to respective controls. BaP and Chr stimulated cytochrome P-450 1A1 (CYP1A1) activity (3, 10, or 30 mg/kg) as measured by ethoxyresorufin O-deethylase (EROD) activity, but Pyr did not. These results indicate that immune function endpoints appear to be more sensitive to these PAHs than measured hepatic CYP450 activity.

The authors thank Jackie EuDaly for assistance in manuscript preparation. Funding was provided by the U.S. EPA Office of Research and Development (ORD). Views represented here are those of the authors and do not reflect the views of the U.S. EPA. The authors have no conflict of interest to declare. This is technical contribution number 5256 of the Clemson University Experiment Station.