In vitro interactions between bovine papillomavirus and human monocytes and macrophages

Limited data suggest that macrophages play a role in the pathogenesis of bovine papillomavirus (BPV) infections. In the present study, interactions between these cells and BPV-1 were explored by exposing in vitro human blood monocytes and monocyte-derived macrophages to purified virions. Immediately or up to 28 days after exposure, cell culture supernatants as well as cell lysates were collected. Interleukin 1 activity was detected in the supernatants of monocytes early after exposure to BPV (0-3 days), but little was found after exposure of macrophages to BPV. In addition, both monocyte and macrophage cell lysates contained episomal BPV DNA which, after an initial decrease in copy number, increased 14-28 days later. Concomitantly, there was progressive disappearance of detectable BPV major capsid protein in cell lysates. These observations support the concept that monocytes and macrophages play a role in the pathogenesis of papillomavirus infections.