Evaluation of acute immunotoxicity of alachlor in male F344/N rats

The immunotoxicity of alachlor was investigated in rats by injecting ip three times with various doses of the compound. Doses used were 1.25, 2.50 and 3.75 mg alachlor/kg body weight. Several types of immune responses were measured, including delayed type hypersensitivity, natural killer cells, hematological parameters, antibody production and organ weight ratios. None of these parameters was affected by any of the doses of the pesticide. The positive control, dexamethasone, elicited the expected responses in all of these measurements. Immunotoxicity of alachlor appears to be minimal and unrelated to carcinogenesis in the rat. However, the possibility of immunotoxicological effects in other species, including humans cannot be ruled out by this study. The metabolism of alachlor in rats yields 23 metabolites, but only five are found in primates, indicating that different excretion patterns and routes are at work in different species. The potential for immunotoxic reactions to metabolites exists for humans.