There’s a nice overview (with links to abstracts) on Biosingularity about this discovery:

Biosingularity » Blog Archive » Newly discovered killer cell fights cancer

A mouse immune cell that plays dual roles as both assassin and messenger, normally the job of two separate cells, has been discovered by an international team of researchers. The discovery has triggered a race among scientists to find a human equivalent of the multitasking cell, which could one day be a target for therapies that seek out and destroy cancer.

“In the same way that intelligence and law enforcement agencies can face deadly threats together instead of separately, this one cell combines the ability to kill foreign pathogens and distribute information about that experience,” says Drew Pardoll, M.D., Ph.D., the Seraph Professor of Oncology at the Johns Hopkins Kimmel Cancer Center.