Natural Killer Cells and Microbes: Beyond the License to Kill

Classically, natural killer (NK) cells are viewed as nonspecific effector cells of the innate immune system that play critical roles in defense against viral infections and nascent neoplasms. Burgeoning evidence in the last decade has provided unprecedented clues that the functional repertoire of NK cells is far more diverse than has been previously appreciated. Alternative NK cell functions relevant for viral infections include (i) tuning and controlling adaptive responses by affecting the survival of other immune cells, and (ii) memory-like or adaptive properties such as antigen-specific recall responses, cytokine-induced memory-like responses and enhanced Fc receptor-dependent functions. Such understudied NK cell properties have gained a lot of attention like the possibility to induce and modulate specific NK cell functions is highly attractive for the development of novel vaccine strategies or immunotherapies to prevent or treat infectious diseases against which there is currently no effective prophylaxis or treatment. However, the precise mechanisms underlying adaptive or rheostat NK cell functions, and how they impact the outcome of different microbial infections remain largely ill-defined, particularly in humans.

In this Research Topic, we seek Reviews, Mini-Reviews, Perspectives, Brief Research Reports and Original Research articles that discuss the latest developments in identification and characterization of NK cell subsets that can mediate adaptive responses or that are involved in immunoregulation via interactions with adaptive and/or innate immune cells in the context of microbial infections.

This research topic welcomes articles highlighting advances from basic NK cell research to clinical applications of NK cells in humans or animal models of infection. More specifically, topics of interest include, but are not limited to:

· Phenotypic and functional characterization of specific NK cell subsets endowed with adaptive or rheostat functions in peripheral blood and tissues
· Protection vs pathogenesis mediated by NK cell rheostat functions in microbial infections
· Protection mediated by adaptive NK cell responses in microbial infections
· Induction/modulation of rheostat or adaptive NK cell functions by vaccination against microbial diseases
· Identification of cellular mechanisms underlying the generation of adaptive NK cells, including microbial ligands that promote adaptive NK cells
· Identification of cellular mechanisms to control NK cell rheostat function and achieve optimal adaptive responses to infection and vaccination
· Development of new methods and technologies to investigate adaptive or rheostat NK cell functions