To study whether extremely low frequency electromagnetic field exposure is able to influence KSHV (Kaposi's sarcoma-associated herpesvirus) latency and replication, and/or KSHV-infected cell growth in vitro.
In vitro studies indicate that several KSHV genes have oncogenic properties, but co-factors are possibly needed for Kaposi's sarcoma development and progression.
To induce the KSHV lytic cycle, exponentially growing cells were treated with 20 ng/ml TPA.
|Chamber||The sample holder consisted of two concentric containers with the inter-space filled with temperature controlled water at 37°C. The cells were placed in a 25 cc Corning flask with 4.8 x 5.2 cm base sides.|
|Additional info||The magnetic flux was perpendicular to the sample. The field was homogeneous to within ±2.5% of the value at the center of the cylindrical exposure volume (11 x 17 cm).|
Extremely low frequency electromagnetic field exposure did not affect the growth and viability of BCBL-1 cells, either stimulated with TPA or not.
The total amount of KSHV DNA detected in electromagnetic field exposed cultures (not stimulated with TPA) did not differ from that of the unexposed controls. However, in the presence of TPA stimulation, total KSHV DNA content was higher in electromagnetic field exposed cell cultures than in control cell cultures at 72 h exposure, but not earlier. That is, extremely low frequency electromagnetic field exposure synergizes with TPA in the stimulation of KSHV DNA synthesis.
Viral DNA increase significantly correlated with increased mean fluorescence intensity/cell for the lytic antigen gp K8.1A/B, but not with percentage of gp K8.1A/B-positive cells or of cells containing virions. Viral progeny produced under electromagnetic field exposure consisted mainly of defective viral particles.