Recent studies have shown that neonatal CD8⁺ T cells can undergo ‘bystander activation’ in response to inflammatory cytokines and produce effector molecules such as IFNγ and granzyme B in the absence of cognate antigen. Some of these cells persist into adulthood. A study by Watson et al. used a multi-omics approach to investigate the epigenetic programmes and transcription factors that enable CD8⁺ T cells to provide innate-like protection. They found that neonatal CD8⁺ T cells are intrinsically poised to produce cytokines, including some, such as IL-13, IL-10 and GM-CSF, that are not commonly associated with CD8⁺ T cells. Stimulation of these cells with the inflammatory cytokines IL-12 and IL-18 induces extensive chromatin remodelling and exposes binding sites for AP-1 transcription factors. By contrast, adult CD8⁺ T cells are less capable of altering chromatin in response to IL-12 or IL-18 stimulation. They also express higher levels of the transcriptional repressor BACH2, which shares binding sites with AP-1 transcription factors and limits the differentiation of effector cells. Overall, their results indicate that neonatal CD8⁺ T cells are much more functionally diverse than their adult counterparts and represent an intrinsically more innate-like lineage, largely due to their enhanced capacity to undergo chromatin remodelling.

最近的研究表明，新生儿 CD8 ⁺ T 细胞可以响应炎症细胞因子而经历“旁观者激活”，并在没有同源抗原的情况下产生 IFNγ 和颗粒酶 B 等效应分子。其中一些细胞会持续到成年期。沃森等人的一项研究。使用多组学方法来研究使 CD8 ⁺ T 细胞提供先天性保护的表观遗传程序和转录因子。他们发现新生儿 CD8 ⁺ T 细胞本质上准备产生细胞因子，包括一些通常与 CD8 ⁺ T 细胞不相关的细胞因子，如 IL-13、IL-10 和 GM-CSF。用炎症细胞因子 IL-12 和 IL-18 刺激这些细胞会诱导广泛的染色质重塑并暴露 AP-1 转录因子的结合位点。相比之下，成人 CD8 ⁺ T 细胞响应 IL-12 或 IL-18 刺激而改变染色质的能力较差。它们还表达较高水平的转录阻遏蛋白 BACH2，它与 AP-1 转录因子共享结合位点并限制效应细胞的分化。总体而言，他们的结果表明，新生儿 CD8 ⁺ T 细胞比成年 CD8 + T 细胞在功能上更加多样化，并且代表了本质上更像先天的谱系，这很大程度上是由于它们进行染色质重塑的能力增强。