Immunotoxicity of aminocarb. III. Exposure route-dependent immunomodulation by aminocarb in mice

Aminocarb, a phenylsubstituted methylcarbamate pesticide (4-dimethylamino-3-methyl-N-carbamate; matacil), previously suspected of a relatively low immunotoxic potential, was administered by four different exposure routes to C57BL/6 mice. A single sublethal exposure by oral and dermal routes stimulated humoral immune response at a relatively low dose; 1/256 LD50 of aminocarb. Intraperitoneal (i.p.) injection decreased the humoral PFC response, whereas inhalation of aminocarb had no marked effect on peripheral immune status in exposed animals. Thus, i.p. exposure resulted in higher immunotoxicity over oral administration of aminocarb. Similarly, marked route-related exposure differences in immunomodulatory effects of aminocarb were noted for mitogenic stimulation of spleen lymphocytes and mixed lymphocyte response. Other indices, such as delayed type hypersensitivity (DTH) and production of interleukin-2 (IL-2) were unchanged. Interestingly, expression of major histocompatibility complex (MHC) class II by purified, lipopolysaccharide (LPS)-stimulated B cells increased equally after i.p. and oral exposures to aminocarb. Overall, a weak immunosuppressive potential of aminocarb was concluded, which was possibly due to indirect interaction of the pesticide with the immune system. However, aminocarb may represent an autoimmunity-inducing toxic.