Characterization and functional analysis of novel circulating NK cell sub-populations.

Natural killer (NK) cells are innate lymphoid cells having potent cytolytic function that provide host defense against microbial infections and tumors. Using our generated monoclonal antibody (mAb), named FE-1H10, new NK cell sub-populations in peripheral blood were identified. The molecules recognized by mAb FE-1H10 were expressed on a sub-population of CD3-CD56dim NK cells. The epitope recognized by mAb FE-1H10 was demonstrated to be N-glycan and proven to be different from CD57. Upon K562 stimulation, the CD56dimFE-1H10+ NK cell sub-population exhibited significantly lower cytolytic function with low ability to degranulate and release cytolytic granules compared to the CD56dimFE-1H10- NK cell sub-population. Moreover, the CD56dimFE-1H10+ NK cells produced less IFN-γ and TNF-α than the CD56dimFE-1H10- NK cells. We demonstrated here that mAb FE-1H10 could identify two sub-populations of circulating CD56dim NK cells with different functions. Our discovery of new sub-populations of NK cells improves our understanding of NK cell biology and may lead to the development of new approaches for NK cell therapy.