Published: Oct 03, 2011 10:45 AM EDT
Updated: Oct 03, 2011 2:31 PM EDT

STOCKHOLM (AP) - The Nobel committee says American Bruce Beutler and Luxembourg-born scientist Jules Hoffmann have shared the 2011 Nobel Prize in medicine with Canadian-born Ralph Steinman.
 
Beutler and Hoffman were cited "for their discoveries concerning the activation of innate immunity."
 
Steinman was honored for "his discovery of the dendritic cell and its role in adaptive immunity."
 
The medicine announcement Monday will be followed in the coming days by announcements for prizes in chemistry, physics, literature, peace and economics.