Vol. 203, No. 8, August 7, 2006. Pages 1837–1841.

Please note that an error appeared in the online early release version of this article. The final html and pdf versions have been corrected. The correction appears below.

A portion of text from the second sentence of the third paragraph under the subheading “Cell-autonomous defense: beyond type I IFNs?” was erroneously deleted. The corrected sentence appears below.

“Coordinated down-regulation of inhibitory ligands and up-regulation of activating ligands can determine the susceptibility of target cells to NK cell–mediated killing (31), but the mechanisms and signaling pathways responsible for altering the expression of these ligands remain largely unknown.”