The immune system must work in an orchestrated way to achieve an optimal response upon detection of antigens. The cells comprising the immune response are traditionally divided into two major subsets, innate and adaptive, with particular characteristics for each type. Type I natural killer T (iNKT) cells are defined as innate-like T cells sharing features with both traditional adaptive and innate cells, such as the expression of an invariant T cell receptor (TCR) and several NK receptors. The invariant TCR in iNKT cells interacts with CD1d, a major histocompatibility complex class I (MHC-I)-like molecule. CD1d can bind and present antigens of lipid nature and induce the activation of iNKT cells, leading to the secretion of various cytokines, such as gamma interferon (IFN-γ) and interleukin 4 (IL-4). These cytokines will aid in the activation of other immune cells following stimulation of iNKT cells. Several molecules with the capacity to bind to CD1d have been discovered, including α-galactosylceramide. Likewise, several molecules have been synthesized that are capable of polarizing iNKT cells into different profiles, either pro- or anti-inflammatory. This versatility allows NKT cells to either aid or impair the clearance of pathogens or to even control or increase the symptoms associated with pathogenic infections. Such diverse contributions of NKT cells to infectious diseases are supported by several publications showing either a beneficial or detrimental role of these cells during diseases. In this article, we discuss current data relative to iNKT cells and their features, with an emphasis on their driving role in diseases produced by pathogenic agents in an organ-oriented fashion.

中文翻译：

---

I 型自然杀伤 T 细胞作为传染病免疫反应的关键调节剂

免疫系统必须以精心策划的方式工作，以在检测到抗原时实现最佳反应。组成免疫反应的细胞传统上分为两个主要亚群，先天性和适应性，每种类型都有特定的特征。I 型自然杀伤 T (iNKT) 细胞被定义为与传统适应性和先天细胞共享特征的先天样 T 细胞，例如表达不变 T 细胞受体 (TCR) 和多种 NK 受体。iNKT 细胞中的不变 TCR 与 CD1d 相互作用，CD1d 是一种主要的组织相容性复合体 I 类 (MHC-I) 样分子。CD1d 可以结合和呈递脂质性质的抗原，并诱导 iNKT 细胞的活化，导致各种细胞因子的分泌，例如 γ 干扰素 (IFN-γ) 和白细胞介素 4 (IL-4)。这些细胞因子将有助于在刺激 iNKT 细胞后激活其他免疫细胞。已经发现了几种能够结合 CD1d 的分子，包括 α-半乳糖神经酰胺。同样，已经合成了几种能够将 iNKT 细胞极化为不同类型的分子，无论是促炎还是抗炎。这种多功能性允许 NKT 细胞帮助或削弱病原体的清除，甚至控制或增加与病原体感染相关的症状。NKT 细胞对传染病的这种不同贡献得到了一些出版物的支持，这些出版物表明这些细胞在疾病中的有益或有害作用。在本文中，我们将讨论与 iNKT 细胞相关的当前数据及其特征，