title: Immunotoxicity of the organochlorine pesticide methoxychlor in female ICR, BALB/c, and C3H/He mice.
abstract: Several types of pesticides, including organochlorines, are known to suppress or modulate immune responses. The present study evaluated the immunotoxicity of the organochlorine pesticide methoxychlor (MXC) in female BALB/c, C3H/He, and ICR mice. Mice were given oral MXC doses of 0, 30, 100, and 300 mg/kg each day for 7 consecutive days. On day 4, the mice also received an intravenous injection of sheep red blood cells (SRBC). The splenic plaque-forming cell (PFC) IgM response and the serum anti-SRBC IgM antibody titer were evaluated while splenic lymphocytes were counted by flow cytometry and the spleen underwent histopathological analysis. Significant decreases in IgM PFC responses were seen in BALB/c, C3H/He, and ICR mice that received MXC doses of 100 and 300 mg/kg. Similar changes in serum anti-SRBC IgM antibody titers occurred in three strain mice. Flow cytometric analysis revealed significantly decreased splenic T-cell (CD3+) populations in a dose dependent manner in BALB/c mice, and in the 300 mg/kg of MXC-treated group of C3H/He mice. Germinal center (GC) B-cell (CD19+PNA+) populations were significantly decreased in the 300 mg/kg of MXC-treated groups of all three mouse strains and in the 30 and 100 mg/kg of MXC-treated groups of BALB/c and C3H/He strain mice. Histopathological analysis revealed decreased cellularity of the periarteriolar lymphoid sheath (PALS; T-cell area) and decreased GC development in all three strains of mice treated with 300 mg/kg MXC. These results suggest that MXC has an immune-suppressive effect in mice, and that our protocol may be useful for rapidly detecting immunosuppression induced by environmental chemicals.
authors.affiliation: Institute of Environmental Toxicology, Ibaraki, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hayashi
authors.forename: Tomoki
authors.initials: T
authors.lastname: Fukuyama
authors.forename: Aya
authors.initials: A
authors.lastname: Ohnuma
authors.forename: Yukari
authors.initials: Y
authors.lastname: Tajima
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kashimoto
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yoshida
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kosaka
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002417:Cattle; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006462:Hemolytic Plaque Technique; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D007107:Immune System / Q000187:drug effects*; D007075:Immunoglobulin M / Q000097:blood; D007165:Immunosuppression Therapy; D007306:Insecticides / Q000633:toxicity*; D008731:Methoxychlor / Q000633:toxicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008813:Mice, Inbred ICR; D013154:Spleen / Q000187:drug effects / Q000473:pathology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology
chemical_list: D006843:Hydrocarbons, Chlorinated; D007075:Immunoglobulin M; D007306:Insecticides; D008731:Methoxychlor