Immunoteratology of chlordane: Cell-mediated and humoral immune responses in adult mice exposed in utero

Abstract

The functional status of the immune system of adult mice prenatally exposed to the chlorinated hydrocarbon pesticide chlordane was evaluated by assessing cell-mediated and humoral immune responses. Gravid BALB c mice fed 0, 0.16, or 8.0 mg/kg chlordane daily throughout gestation produced viable, overtly normal offspring. At 101 days of age cell-mediated immune (CMI) responses were measured by the contact hypersensitivity response to oxazolone. Offspring were sensitized by application of oxazolone to the denuded flank and 5 days later challenged by percutaneous application of oxazolone to the ear. Degree of induration was determined by daily micrometer measurement of ear thickness for 3 days after challenge. Offspring in the higher dose group had a significantly ( p < 0.01) depressed CMI response when compared to offspring of the control or lower dose groups. The primary humoral response to sheep red blood cell (sRBC) innoculation was determined at 101 days of age using the hemolytic plaque assay. Subjects were immunized with washed sRBC. IgM antibody released from the spleen cells was detected by addition of complement which caused lysis of the sRBC's. No significant differences existed between the number of plaque-forming cells (PFC) produced by spleen cells from either chlordane-treated group or the vehicle-control group. Results of this study revealed two significant findings: (1) severe depression of the functional CMI response in apparently normal treated offspring, but (2) no effect on the T-cell-dependent humoral immune response. The effect of chlordane on CMI and PFC responses might be explained by a reduction in the activity or number of T effector cells.