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Characterization of KIR + NKG2A + Eomes− NK‐like CD8+ T cells and their decline with age in healthy individuals
Author(s) -
Kasakovski Dimitri,
Zeng Xiangbo,
Lai Jing,
Yu Zhi,
Yao Danlin,
Chen Shaohua,
Zha Xianfeng,
Li Yangqiu,
Xu Ling
Publication year - 2021
Publication title -
cytometry part b: clinical cytometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 61
eISSN - 1552-4957
pISSN - 1552-4949
DOI - 10.1002/cyto.b.21945
Subject(s) - biology , immunology , population , senescence , cd8 , phenotype , immune system , flow cytometry , cytotoxic t cell , cord blood , microbiology and biotechnology , immunosenescence , genetics , in vitro , medicine , gene , environmental health
Background KIR+NKG2A + Eomes+ CD8+ T cells, which are preferentially found with a T EMRA (CD45RA + CCR7−) phenotype while having the capacity to rapidly produce IFN‐γ in response to innate stimulation (IL‐12 and IL‐18), have been demonstrated to exist in human cord blood and the adult blood circulation. This highly responsive T‐cell type was termed NK‐like CD8+ T cells due to their capability to act in an innate immune fashion in mice similar to NK cells. However, KIR+NKG2A + CD8+ T cells that are Eomes− represent a small proportion of unconventional T cells that have not been described until now. Methods We compare the distribution of the memory phenotypes and senescence‐associated markers of two T‐cell subsets by multicolor flow cytometry in 10 cord blood samples and 105 healthy individuals (HIs) ranging from 6 to 84 years of age. Results We found that the Eomes+ population has a higher differentiation degree than the Eomes− population. T cells in the Eomes− subset show proportionally less T EMRA phenotypes while instead preferentially displaying a more naïve and T CM phenotype. Furthermore, the Eomes− population was shown to linearly decrease with age, while the Eomes+ population exhibited more senescence‐associated characteristics, such as CD57 expression and loss of CD28. Conclusion Overall, the KIR+NKG2A + Eomes− CD8+ T‐cell population shares similar characteristics with the Eomes+ population, although with a lower degree of differentiation, lower senescence marker expression, and a proportional decrease with age. Thus, we suspect that KIR+NKG2A + Eomes‐CD8+ T cells may represent a less differentiated stage of the NK‐like CD8+ T‐cell subset.