Primary human fibroblasts are permissive for porcine cytomegalovirus in vitro

Abstract

Xenotransplantation with pig organs is being considered to alleviate donor organ shortages; however, the risk of introducing porcine viruses to humans is exaggerated in this setting. Accordingly, the goal of this study was to determine the infectious potential of porcine cytomegalovirus (PCMV), a xenozoonotic virus of interest, in human fibroblasts in vitro. Confluent cells were incubated with either live PCMV or controls. Infection was investigated by light microscopy/neutral red staining, by RT-PCR and sequencing, and by Western blotting. Neutralization experiments were also performed. Cells incubated with PCMV demonstrated significant cytopathic effect by 7 days post-infection. Also, RT-PCR sequencing identified PCMV DNA polymerase in infected cells. In Western blots, monoclonal antibodies (mAbs) to human CMV glycoprotein B and pig serum presumed to contain anti-PCMV antibodies detected PCMV proteins by 19 days post-infection. Furthermore, one of these mAbs and the pig serum neutralized PCMV infection. Western blots and neutralization studies using a mAb to a human herpes virus 6 membrane glycoprotein provided no concrete evidence for a biological relationship between PCMV and human herpes virus 6. These results demonstrate that PCMV can infect human fibroblasts in vitro.