In vivo prenatal chlordane exposure induces development of endogenous inflammatory macrophages

Macrophages (m⊘s), important cells in host resistance, undergo a series of biochemical changes during their progression from the resident to the fully activated stage. Both resident and inflammatory m⊘s are characterized by some unique properties. In the present study, female BALB/c mice were prenatally treated with 8 mg/kg body weight of chlordane, a cyclodiene poly‐chlorinated hydrocarbon that appears to reduce immunocompetence by selectively impairing m⊘ function. Therefore, we examined functions in m⊘s from chlordane‐treated mice that had been stimulated with thioglycollate. The 5'‐nucleotidase activity, present in high levels in resident m⊘s but low levels in inflammatory m⊘s was elevated in resident m⊘s from vehicle‐exposed animals. Conversely, inflammatory m⊘s from these animals showed significantly diminished levels of this function. Moreover, chlordane‐exposed m⊘s, regardless of whether they were resident or inflammatory, exhibited decreased 5'‐nucleotidase responses. When a second function, transferrin receptor binding, was analyzed, vehicle‐treated inflammatory m⊘s displayed high levels of activity whereas the resident m⊘s showed very little transferrin binding. However, both resident and inflammatory m⊘s from the chlordane‐exposed group demonstrated transferrin binding activity similar in magnitude to that of the vehicle‐treated inflammatory m⊘s. Finally, two‐dimensional polyacrylamide gel electrophoresis analysis of m⊘s from chlordane‐exposed mice have characteristics of normal m⊘s that have advanced to the inflammatory stage.