Cytokine-Based Generation of CD49a+Eomes-/+ Natural Killer Cell Subsets.

Xiang Ni,Zhigang Tian,Binqing Fu,Rui Sun,Jinghe Zhang,Haiming Wei

doi:10.3389/fimmu.2018.02126

Abstract

Recent studies have identified CD49a+Eomes− and CD49a+Eomes+ subsets of tissue-resident NK (trNK) cells in different organs of the mouse. However, the characteristics of CD49a+Eomes−/+ NK cell development and the regulation of Eomes expression in NK cells remain unclear. Here, we established an in vitro cytokine-based feeder-free system in which bone marrow progenitor cells differentiate into CD49a+ NK cells. IL-15 was identified as being the key cytokine in this system that supported the development and maintenance of CD49a+ NK cells. The CD49a+ NK cells generated were Eomes−CD49b− and shared the same phenotype as hepatic trNK cells. IL-4 induced the expression of Eomes in generated NK cells and converted them into CD49a+Eomes+ cells, which were phenotypically and functionally similar to uterine trNK cells. Moreover, the IL-4/STAT6 axis was identified as being important in the generation of CD49a+Eomes+ induced NK cells. Collectively, these studies describe an approach to generate CD49a+Eomes−/+ subsets of NK cells and demonstrate important roles for IL-15 and IL-4 in the differentiation of these cells. These findings have potential for developmental research underlying the generation of different subsets of NK cells and the application of adoptive NK cell transfer therapies.

Highlights

Over recent years, researchers have shown increasing levels of interest in CD49a+ tissue-resident natural killer cells, which have been found in a range of organs such as the liver, uterus, skin and salivary glands (SG) [1,2,3,4,5,6].These tissue-resident NK (trNK) cells function to counter potential invading organisms [7], similar to conventional NK cells, and contribute to multiple biological processes
To investigate the developmental conditions of CD49a+ NK cells, we established an in vitro system in which bone marrow (BM) cells differentiated into NK1.1+CD49a+ cells upon culture in multiple cytokine cocktails without feeders
Fourth, IL-15 and IL-2 were added to the culture and supplemented with low concentrations of stem cell factor (SCF) and fms-like tyrosine kinase 3 ligand (Flt3L), FIGURE 1 | Generation and identification of CD49a+ NK cells. (A) Schematic of the procedure used to generate CD3−CD19−NK1.1+CD49a+ cells. (B) Gating strategy and representative flow plots of generated live CD45+CD3−CD19−NK1.1+CD49a+ cells

Summary

Introduction

Researchers have shown increasing levels of interest in CD49a+ tissue-resident natural killer (trNK) cells ( referred to as a group of innate lymphoid cells, ILC1s), which have been found in a range of organs such as the liver, uterus, skin and salivary glands (SG) [1,2,3,4,5,6]. These trNK cells function to counter potential invading organisms [7], similar to conventional NK (cNK) cells, and contribute to multiple biological processes. TrNK cells and cNK cells express a range of similar markers, such as NK1.1, NKp46, NKG2D, and T-bet, but can be distinguished by the high expression levels of CD49a, CD69, and TNF-related apoptosis-inducing ligand (TRAIL) by trNK cells; cNK cells are CD49b+ [2, 11, 12].

Methods

Results

Conclusion