Human herpesvirus-6 infection may predispose cells to superinfection by other viruses.

Double infection of cells by HHV-6, Epstein-Barr virus (EBV) and by human immunodeficiency virus (HIV-1) can enhance viral effects though genetic transactivation. It remained to be clarified, however, by which mechanism different viruses may enter the same cell. We have shown that HHV-6 infection of immature lymphoid cells rigidifies the cytoplasmic membrane and causes receptor proteins for viruses such as CD4 for HIV-1 and CR2 for EBV to be expressed. In our experiments, HHV-6 infected cells were superinfected by HIV1 and caused enhanced cell death. The mechanisms by which receptors were expressed after HHV-6 infection appears independent of cell membrane rigidification alone and is suppressed by cycloheximide only to a certain extent.