Human cytomegalovirus triggers an immune response before it actually enters the cell, according to a report from researchers at the University of Wisconsin-Madison and the University of Massachusetts (T. Compton et al., "Human cytomegalovirus activates inflammatory cytokine responses via CD14 and toll-like receptor 2," J Virol, in press).
The immune system is activated when the virus comes into contact with toll-like receptors on the cell. "No one knew … that was even possible," says Teresa Compton, associate professor of oncology at Wisconsin. "People thought the virus actually had to get into the cell and start doing its business before the host knew it was there."
Three other viruses (respiratory syncytial, murine mammary tumor, and measles) also trigger the immune system when they come into contact with the toll-like receptors. "It may be this is a common molecular trigger," says Compton. "We're trying to understand the specific molecular trigger–what does this alarm system recognize on all these viruses that triggers its activation response," she says.
Compton also wants to see if other herpes viruses also trigger toll-like receptors. Understanding this interaction, she notes, would give vaccine makers a better picture of the way the virus triggers the immune system.