Diesel Exhaust-Associated Gas Components Enhance Chemokine Production by Cervical Lymph-Node Cells from Mice Immunized with Sugi Basic Proteins

Abstract

Previously, we showed that exposure to diesel exhaust (DE) increased inflammatory cells in the airway and cytokine production from local lymph-node cells after antigen stimulation. To clarify the role of particle-free diesel gas components in induction of allergic inflammation, we compared the effect of DE and gas components on pollen-antigen-stimulated chemokine production by cervical lymph nodes (CLN) cells in BALB/c mice. Groups of mice were exposed to 0 (control), 1.0 mg diesel exhaust particles (DEP)/m³ (DE), or filtered 1.0 mg DEP/m³ DE (gas) for 12 h daily for 5 wk. Each group of mice was injected intraperitoneally with sugi basic protein (SBP), a major allergen of Japanese cedar pollen, immediately before their exposure to DE or gas. On days 14 and 35, each mouse received an additional SBP intranasally. Exposure to DE or gas did not affect the lymphocyte subpopulations of CLN. Culture supernatants of CLN cells from DE-exposed, SBP-immunized mice had significantly increased levels of monocyte chemoattractant protein-1. Exposure to gas significantly increased the amount of thymus- and activation-regulated chemokine and macrophage inflammatory proteins-1α in the CLN cells from SBP-immunized mice. These results suggest that Gas components as well as DEP may differentially regulate production of chemokines at local sites.

We thank Dr. T. Kobayashi for his encouragement and S. Shimizu, K. Ohnishi, and K. Mishima for their excellent technical assistance. The authors thank Dr. T. Endo (Jikei University School of Medicine) for providing SBP.