Forslund Elin, Sohlberg Ebba, Enqvist Monika, Olofsson Per E, Malmberg Karl-Johan, Önfelt Björn
Department of Microbiology, Tumor and Cell Biology, Science for Life Laboratory, Karolinska Institutet, 171 65 Stockholm, Sweden;
Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden;
J Immunol. 2015 Oct 1;195(7):3374-81. doi: 10.4049/jimmunol.1500171. Epub 2015 Aug 28.
NK cells are functionally educated by self-MHC specific receptors, including the inhibitory killer cell Ig-like receptors (KIRs) and the lectin-like CD94/NKG2A heterodimer. Little is known about how NK cell education influences qualitative aspects of cytotoxicity such as migration behavior and efficacy of activation and killing at the single-cell level. In this study, we have compared the behavior of FACS-sorted CD56(dim)CD57(-)KIR(-)NKG2A(+) (NKG2A(+)) and CD56(dim)CD57(-)KIR(-)NKG2A(-) (lacking inhibitory receptors; IR(-)) human NK cells by quantifying migration, cytotoxicity, and contact dynamics using microchip-based live cell imaging. NKG2A(+) NK cells displayed a more dynamic migration behavior and made more contacts with target cells than IR(-) NK cells. NKG2A(+) NK cells also more frequently killed the target cells once a conjugate had been formed. NK cells with serial killing capacity were primarily found among NKG2A(+) NK cells. Conjugates involving IR(-) NK cells were generally more short-lived and IR(-) NK cells did not become activated to the same extent as NKG2A(+) NK cells when in contact with target cells, as evident by their reduced spreading response. In contrast, NKG2A(+) and IR(-) NK cells showed similar dynamics in terms of duration of conjugation periods and NK cell spreading response in conjugates that led to killing. Taken together, these observations suggest that the high killing capacity of NKG2A(+) NK cells is linked to processes regulating events in the recognition phase of NK-target cell contact rather than events after cytotoxicity has been triggered.
自然杀伤（NK）细胞通过自身主要组织相容性复合体（MHC）特异性受体进行功能训练，包括抑制性杀伤细胞免疫球蛋白样受体（KIR）和凝集素样CD94/NKG2A异二聚体。关于NK细胞训练如何在单细胞水平上影响细胞毒性的定性方面，如迁移行为以及激活和杀伤效力，目前所知甚少。在本研究中，我们通过基于微芯片的活细胞成像对迁移、细胞毒性和接触动力学进行定量，比较了荧光激活细胞分选术（FACS）分选的CD56（dim）CD57（-）KIR（-）NKG2A（+）（NKG2A（+））和CD56（dim）CD57（-）KIR（-）NKG2A（-）（缺乏抑制性受体；IR（-））人NK细胞的行为。NKG2A（+）NK细胞表现出更动态的迁移行为，并且与靶细胞的接触比IR（-）NK细胞更多。一旦形成共轭体，NKG2A（+）NK细胞也更频繁地杀死靶细胞。具有连续杀伤能力的NK细胞主要存在于NKG2A（+）NK细胞中。涉及IR（-）NK细胞的共轭体通常寿命更短，并且当与靶细胞接触时，IR（-）NK细胞的激活程度不如NKG2A（+）NK细胞，这从它们降低的铺展反应中可以明显看出。相比之下，在导致杀伤的共轭体中，NKG2A（+）和IR（-）NK细胞在共轭期持续时间和NK细胞铺展反应方面表现出相似的动力学。综上所述，这些观察结果表明，NKG2A（+）NK细胞的高杀伤能力与调节NK-靶细胞接触识别阶段事件的过程有关，而不是与细胞毒性触发后的事件有关。
