a Department of Immunology , School of Public Health, International Campus, Tehran University of Medical Sciences , Tehran , Iran.
b Department of Immunology , School of Public Health, Tehran University of Medical Sciences , Tehran , Iran.
Immunopharmacol Immunotoxicol. 2019 Feb;41(1):16-24. doi: 10.1080/08923973.2019.1566925. Epub 2019 Feb 4.
T helper 17 (Th17) cells were first described as a novel T helper cell lineage independent from Th1 and Th2 subsets. Th17 cells play vital roles in inflammation and tumor immunity. It causes the dissipation of antitumor immunity and contribution to the survival of tumor cells, worsening tumor growth and metastasis. Tumor-infiltrating Th17 cells were seen innumerous cancers in mice and humans. There has been an association between intratumoral Th17 cell infiltration and both good and bad prognoses. Besides the protumoral roles defined for IL-17 andTh17 cells, several reports have shown that Th17 cells also drive antitumoral immunity. Various mechanisms by which Th17 cells control tumor growth are as following: recruitment of several immune cells including DCs, CD4 T cells, and CD8 T cells within tumors, activation of CD8 T cells, and probably plasticity toward Th1 phenotype, related to IFN- and TNF- production. Regulatory T cells (Tregs) have been exhibited to infiltrate human tumors and are believed to restrict antitumor immunity. The effect of Treg cells has been more controversial. Whereas some studies have proposed that a high density of Treg cells within the tumor associated with a poor clinical prognosis, other studies have presented a positive clinical prognosis, underlining the importance of elucidating the clinical significance of Treg cells further. Treg and Th17 cells play both positive and negative roles in regulating antitumor immune responses. In spite of the presence of these cells, yet some tumors develop and grow. These T cells by themselves are not adequate to efficiently mount antitumor immune responses.
辅助性 T 细胞 17（Th17）细胞最初被描述为一种新型的辅助性 T 细胞谱系，与 Th1 和 Th2 亚群无关。Th17 细胞在炎症和肿瘤免疫中发挥重要作用。它导致抗肿瘤免疫的消散，并有助于肿瘤细胞的存活，从而使肿瘤生长和转移恶化。在小鼠和人类的无数癌症中都观察到肿瘤浸润性 Th17 细胞。肿瘤内 Th17 细胞浸润与良好和不良预后之间存在关联。除了已定义的 IL-17 和 Th17 细胞的促肿瘤作用外，有几项报道表明 Th17 细胞也可驱动抗肿瘤免疫。Th17 细胞控制肿瘤生长的各种机制如下：招募包括树突状细胞（DC）、CD4 T 细胞和 CD8 T 细胞在内的几种免疫细胞进入肿瘤内，激活 CD8 T 细胞，以及可能向与 IFN-和 TNF-产生相关的 Th1 表型发生可塑性。调节性 T 细胞（Treg）已被证明会浸润人类肿瘤，并被认为限制了抗肿瘤免疫。Treg 细胞的作用更具争议性。虽然一些研究提出肿瘤内 Treg 细胞的高密度与不良的临床预后相关，但其他研究提出了积极的临床预后，这强调了进一步阐明 Treg 细胞的临床意义的重要性。Treg 和 Th17 细胞在调节抗肿瘤免疫反应中发挥着正反两方面的作用。尽管存在这些细胞，但仍有一些肿瘤会发展和生长。这些 T 细胞本身不足以有效地产生抗肿瘤免疫反应。
