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Th1 细胞的概述
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Th1 细胞是T辅助细胞（T-helper cells, Th）家族的一种重要亚型，属于CD4+ T细胞群体。Th1 细胞通过分泌细胞因子来调控免疫系统的细胞介导免疫反应，尤其是针对病毒、细胞内病原体（如某些细菌和寄生虫）及某些肿瘤细胞的免疫防御。Th1 细胞主要通过促进细胞毒性T细胞（CTLs）的增殖和激活，触发强效的炎症反应。
Th1 细胞的分化和形成机制
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Th1 细胞的功能
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Th1 细胞通过分泌特定的细胞因子来执行其功能，主要包括IL-2和干扰素γ（IFN-γ），这些细胞因子在免疫系统中发挥多种关键作用：
- IL-2（白介素-2）：IL-2 主要促进T细胞增殖。当Th1细胞分泌IL-2时，T细胞（包括效应T细胞和记忆T细胞）大量增殖，特别是在TCR被激活的情况下。IL-2在感染严重时的高浓度释放，会促使大量效应细胞的增殖，增强机体的免疫应答。
- IFN-γ（干扰素γ）：IFN-γ 是Th1 细胞的主要效应分子之一，它能够激活多个细胞类型的干扰素受体，启动磷酸化级联反应，诱导抗病毒和抗细菌基因（称为干扰素刺激基因，ISGs）的表达。通过这一机制，IFN-γ能：
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Th1 细胞在肿瘤免疫中的作用
肿瘤免疫中的Th1细胞起到了至关重要的调控作用，它们通过激活细胞毒性T细胞和增强巨噬细胞的活性，直接或间接地攻击肿瘤细胞。具体机制如下：
Th1 细胞在过敏反应中的作用
与Th2 细胞在过敏反应中的主要作用不同，Th1 细胞通常与过敏反应的抑制有关。Th1和Th2细胞之间存在免疫平衡关系，Th1 细胞可以通过多种机制抑制过敏反应：
- IFN-γ 的抗过敏作用：Th1 细胞分泌的IFN-γ能够抑制Th2细胞的活化和功能，从而减少Th2细胞介导的IgE产生和肥大细胞的脱颗粒反应。这一机制可以减少过敏反应的发生。
- 免疫应答的平衡：在免疫应答中，Th1 细胞主导的细胞介导免疫和Th2 细胞主导的体液免疫相互抑制。因此，当Th1 细胞活化并主导免疫应答时，Th2 细胞的效应功能会被抑制，从而降低过敏反应的发生风险。
参考文献
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