University of Alabama at Birmingham researchers have discovered anthrax spores enter cells through something called Mac-1, a receptor located on the surface of certain cells. The scientists said their finding marks the first study to determine exactly how the bacteria get inside cells.

The researchers said the discovery is a milestone in ongoing efforts to protect humans from bioterrorism and biological warfare, and will speed the development of new drugs and vaccines to fight or prevent anthrax infection.

"We know anthrax infection can occur in wild and domestic animals, but in humans this disease is extremely rare and very dangerous," said Professor John Kearney, co-author of the study. "It is a bioweapon."

The study that included researchers Claudia Oliva and Melissa Swiecki is reported in the early online edition of the Proceedings of the National Academy of Sciences and will soon appear in a print edition.