Researchers discover how smallpox kills

While smallpox has been eradicated from the planet as a naturally occurring  virus, it still remains a high level biothreat. Researchers at the Centers for Disease Control and Prevention in Atlanta, Georgia, have made an important step in fighting the virus - they have identified how it kills humans.

In a research report published in online The FASEB Journal, the researchers describe how the immune system is crippled by smallpox, which attacks molecules that the body makes to block viral replication. The discovery, which clears up a fundamental mystery about smallpox, lays the groundwork for developing antiviral treatments.

"The re-emergence of pox viruses has potentially devastating consequences for people worldwide, as increasing numbers of people lack immunity to smallpox," Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal, told Science Daily.

"Understanding exactly how pox viruses disrupt our immune systems can help us develop defenses against natural and terror-borne pox viruses."

Scientists at the Centers for Disease Control and Prevention in Atlanta produced the variola virus' recombinant proteins as well as a similar virus that causes monkeypox in monkey populations. The cells infected with variola and monkeypox, the researchers observed, produced a protein that blocked a wide range of human interferons, which are produced by the human immune system to stop viral replication.

"These studies demonstrate the production of an interferon binding protein by variola virus and monkeypox virus, and point at this viral anti-interferon protein as a target to develop new therapeutics and protect people from smallpox and related viruses," Antonio Alcami, Ph.D., a collaborator on the study from Madrid, Spain, told Science Daily.

"A better understanding of how variola virus, one of the most virulent viruses known to humans, evades host defenses will help up to understand the molecular mechanisms that cause disease in other viral infections."