Natural Killer (NK) cells are part of the innate immune system, and as specialized first responder cells they can eliminate cancerous cells, virally infected cells, and deleterious pathogens. Understanding how NK cells recognize such diverse targets has remained a challenge for many years. Furthermore, scientists are still investigating the many mechanisms employed by these deleterious targets to evade detection by NK cells. Vigorous work by Professor Ofer Mandelboim and his colleagues from the Concern Foundation laboratories at the Lautenberg Center of the Medical Faculty at the Hebrew University of Jerusalem, led to the discovery of the ways NK cells recognize many important viruses, including influenza and the human cytomegalovirus. Moreover, this team of investigators uncovered how NK cells recognize bacteria and fungi; an important step forward for clinical research, since many of these pathogens are currently untreatable. In addition, the investigators discovered how NK cells recognize and kill different cancers, and concomitantly how these cancers evade elimination by NK cells.