Researchers working in a high containment laboratory at the CDC in Atlanta, GA have discovered how the smallpox virus kills. In a study published in the FASEB Journal, the team says that the virus, now eradicated by vaccination, cripples the immune systems by attacking molecules made by our bodies to block viral replication.

 In a high containment laboratory at the Centers for Disease Control and Prevention in Atlanta, scientists produced the recombinant proteins from the variola virus and a similar virus that affects monkeys, causing monkeypox.  The researchers then showed that cells infected
with variola and monkeypox produced a protein that blocks a wide range of human interferons, which are molecules produced by our immune systems meant 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," said Antonio Alcami, Ph.D., a collaborator on the study from Madrid, Spain. "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."

"The re-emergence of pox viruses has potentially devastating consequences for people worldwide, as increasing numbers of people lack immunity to smallpox," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Understanding exactly how pox viruses disrupt our immune systems can help us develop defenses against natural and terror-borne pox viruses."

Citation: María del Mar Fernández de Marco, Alí Alejo, Paul Hudson, Inger K. Damon, and Antonio Alcami. The highly virulent variola and monkeypox viruses express secreted inhibitors of type I interferon', Dec.  2009,  FASEB J.,  doi:10.1096/fj.09-144733