Application of CD27 as a marker for distinguishing human NK cell subsets

It has long been recognized that human NK cells can be divided into two phenotypically and functionally distinct subsets, based on their levels of expression of CD56. We recently found that CD27 distinguishes subsets of mature mouse NK cells. Here we report that CD27 can be used as a marker to discriminate human NK cell subsets. The majority of peripheral blood human NK cells were CD27^lo/CD56^dim NK cells, whereas the minor CD27^hi NK cell population correspondingly displayed a CD56^bright phenotype. Distinctions between CD27^lo and CD27^hi NK cells in their receptor expression and typical NK cell functions such as cytotoxicity and cytokine production can be easily delineated. Therefore, we propose the dual use of CD27 and CD56 as maturation/subset markers for human NK cells. The identification of CD27 subsets in both mice and humans will allow more accurate projections of the role of NK cell subsets in murine models of human pathologies where NK cells are involved.