γδ T cells are unconventional T cells that function on the border of innate and adaptive immunity. They are suggested to play important roles in neonatal and infant immunity, although their phenotype and function are not fully characterized in early childhood. We aimed to investigate γδ T cells in relation to age, prematurity and cytomegalovirus (CMV) infection. Therefore, we used flow cytometry to characterize the γδ T-cell compartment in cord blood and peripheral blood cells from 14-day-, 2-year- and 5-year-old children, as well as in peripheral blood samples collected at several time points during the first months of life from extremely premature neonates. γδ T cells were phenotypically similar at 2 and 5 years of age, whereas cord blood was divergent and showed close proximity to γδ T cells from 14-day-old neonates. Interestingly, 2-year-old children and adults showed comparable Vδ2+ γδ T-cell functionality toward both microbial and polyclonal stimulations. Importantly, extreme preterm birth compromised the frequencies of Vδ1+ cells and affected the functionality of Vδ2+ γδ T cells shortly after birth. In addition, CMV infection was associated with terminal differentiation of the Vδ1+ compartment at 2 years of age. Our results show an adult-like functionality of the γδ T-cell compartment already at 2 years of age. In addition, we demonstrate an altered γδ T-cell phenotype early after birth in extremely premature neonates, something which could possible contribute to the enhanced risk for infections in this vulnerable group of children.

中文翻译：

---

婴儿期 γδ T 细胞区室的表征揭示了新生儿早期和 2 岁时的明显差异。


γδ T 细胞是非常规 T 细胞，在先天免疫和适应性免疫的边界上发挥作用。尽管它们的表型和功能在幼儿期尚未完全表征，但它们被认为在新生儿和婴儿免疫中发挥着重要作用。我们的目的是研究 γδ T 细胞与年龄、早产和巨细胞病毒 (CMV) 感染的关系。因此，我们使用流式细胞术来表征 14 天、2 岁和 5 岁儿童的脐带血和外周血细胞以及多次采集的外周血样本中的 γδ T 细胞区室。极早产新生儿出生后最初几个月的点。 2 岁和 5 岁时的 γδ T 细胞表型相似，而脐带血则不同，与 14 天新生儿的 γδ T 细胞非常接近。有趣的是，2 岁儿童和成人对微生物和多克隆刺激表现出类似的 Vδ2+ γδ T 细胞功能。重要的是，极端早产会损害 Vδ1+ 细胞的频率，并在出生后不久影响 Vδ2+ γδ T 细胞的功能。此外，CMV 感染与 2 岁时 Vδ1+ 室的终末分化有关。我们的结果显示 γδ T 细胞区室在 2 岁时就已经具有成人样的功能。此外，我们还发现极早产儿出生后早期 γδ T 细胞表型发生了改变，这可能会增加这一弱势儿童群体的感染风险。