Association between extremely low frequency electromagnetic fields (ELF-EMF) and human cancers is controversial, and few studies have been conducted on their influence on oncogenic viruses. We studied the effects of 1 mT, 50 Hz sine waves, applied for 24-72 h, on Kaposi's sarcoma (KS)-associated herpesvirus (KSHV or HHV-8) in BCBL-1, a latently infected primary effusion lymphoma (PEL) cell line. ELF-EMF exposure did not affect the growth and viability of BCBL-1 cells, either stimulated or not with TPA. The total amount of KSHV DNA detected in ELF-EMF exposed cultures not stimulated with TPA did not differ from that of the unexposed controls (P = ns). However, in the presence of TPA stimulation, total KSHV DNA content was found higher in ELF-EMF exposed than in control BCBL-1 cultures (P = .024) at 72 h exposure, but not earlier. Viral DNA increase significantly correlated with increased mean fluorescence intensity/cell for the lytic antigen gp K8.1A/B (P < .01), but not with percentage of gp K8.1A/B-positive cells or of cells containing virions. Viral progeny produced under ELF-EMF exposure consisted mainly of defective viral particles.
(c) 2005 Wiley-Liss, Inc.