IMMUNE FUNCTION AND HOST-DEFENSE IN RODENTS EXPOSED TO 60-HZ MAGNETIC-FIELDS

This study was conducted to evaluate the influence of subchronic expos ure to pure, linearly polarized 60-Hz magnetic fields (MF) on the host immune response in mice. The experimental design was as follows: thre e groups were exposed continuously (18.5 hr/day) to MF at field streng ths of 0.02, 2, or 10 gauss (G), one group was exposed intermittently (1 hr on/1 hr off) to MF at a field strength of 10 G, and one group se rved as a sham control. Experimental endpoints included spleen and thy mus weights and cellularity, antibody-forming cell (AFC) response, del ayed-type hypersensitivity (DTH) response, splenic lymphocyte subset a nalysis, susceptibility to infection with Listeria monocytogenes, and natural killer (NK) cell activity. No differences in body weight, lymp hoid organ weight, or lymphoid organ cellularity were observed in any MF-exposed group in comparison to sham controls. Likewise, no statisti cally significant differences were found in comparisons of AFC respons es. Isolated statistically significant differences from control were o bserved in MF-exposed mice in the DTH assay, although no clear dose-re lated pattern of altered activity was seen. Splenic lymphocyte subset parameters examined were within normal limits in all groups, and no di fferences between control and MF-exposed mice were found. Host resista nce to bacterial infection was not altered at any MF exposure examined in this study. Finally, although apparently dose-related, statistical ly significant alterations were observed in an initial study of NK cel l function, repeat studies failed to demonstrate a consistent pattern Of alteration. (C) 1996 Society of Toxicology.