Griswold Ryan Q, Brightman Spencer E, Soria Zavala Karla, Ordaz-Arias Manuel Azaid, Djassemi Navid, Thota Rukman R, Naradikian Martin S, Dose Hannah, Alarcon Suzie, Vijayanand Pandurangan, Peters Bjoern, Miller Aaron M, Cohen Ezra E W, Schoenberger Stephen P
University of California San Diego, La Jolla, California, USA.
Center for Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, California, USA.
J Immunother Cancer. 2025 Sep 4;13(9):e012209. doi: 10.1136/jitc-2025-012209.
CD4 T cells play a critical role in the positive and negative regulation of cellular immunity through the many functional subsets they comprise. The progressive growth of immunogenic tumors which nonetheless generate mutation-specific T cells suggests that effective immune control may be avoided or suppressed at the level of the neoantigen-specific CD4 T-cell response. Despite their importance, little is known about the ontogeny, architecture, and development of the CD4 NeoAg-specific repertoire induced by progressively growing tumor.
We used a tetramer specific for a validated neoantigen, CTLC/I-A, to characterize the ontogeny of natural CD4 T-cell responses to an aggressive and poorly immunogenic major histocompatibility complex class II-deficient tumor, squamous cell carcinoma VII (SCC VII), during progressive growth or following therapeutic peptide vaccination using a combination of flow cytometry, single-cell genomics, and T-cell receptor (TCR) gene engineering.
We find that the natural CD4 T-cell response to a growing tumor is phenotypically and functionally diverse, with distinct subsets including type 1 helper, T follicular helper-like, and regulatory T cell (Treg) lineages appearing as early as 9 days after tumor implantation. Therapeutic vaccination using the CLTC peptide in adjuvant plus α-programmed cell death protein-1 reduces the frequency of CLTC-specific Treg in both tumor and tumor-draining lymph node. Single-cell transcriptomic analysis of CLTC-specific CD4 T cells recapitulated and extended the diversity of the response, with TCRs of varying affinity found within each functional subset. The TCR affinity differences did not strictly correlate with function, however, as even the lowest affinity TCRs isolated from Treg can mediate therapeutic efficacy against established tumors in the setting of adoptive cellular therapy (ACT).
These findings offer unprecedented insight into the functional diversity of a natural neoantigen-specific CD4 T-cell response and show how immunotherapeutic intervention influences the phenotype, magnitude, and efficacy of the antitumor immune response. This information could lead to new approaches to immune monitoring in the clinical setting of checkpoint blockade immunotherapy and cancer vaccines. Furthermore, we show that Treg can be a potent source of TCRs that can mediate therapeutic benefit in the setting of ACT.
CD4 T细胞通过其包含的众多功能亚群在细胞免疫的正向和负向调节中发挥关键作用。免疫原性肿瘤不断生长，却仍能产生突变特异性T细胞，这表明在新抗原特异性CD4 T细胞反应水平上，有效的免疫控制可能被避免或抑制。尽管其很重要，但对于由逐渐生长的肿瘤诱导的CD4新抗原特异性库的个体发生、结构和发育知之甚少。
我们使用针对经过验证的新抗原CTLC/I-A的四聚体，通过流式细胞术、单细胞基因组学和T细胞受体（TCR）基因工程相结合的方法，来表征天然CD4 T细胞对侵袭性且免疫原性差的主要组织相容性复合体II类缺陷肿瘤——鳞状细胞癌VII（SCC VII）在逐渐生长过程中或治疗性肽疫苗接种后的反应个体发生。
我们发现，对生长肿瘤的天然CD4 T细胞反应在表型和功能上具有多样性，早在肿瘤植入后9天就出现了不同的亚群，包括1型辅助性T细胞、滤泡辅助性T细胞样和调节性T细胞（Treg）谱系。使用CLTC肽佐剂加α程序性细胞死亡蛋白1进行治疗性疫苗接种可降低肿瘤和肿瘤引流淋巴结中CLTC特异性Treg的频率。对CLTC特异性CD4 T细胞的单细胞转录组分析概括并扩展了反应的多样性，在每个功能亚群中都发现了具有不同亲和力的TCR。然而，TCR亲和力差异与功能并不严格相关，因为即使从Treg中分离出的最低亲和力TCR在过继性细胞疗法（ACT）中也能介导对已建立肿瘤的治疗效果。
这些发现为天然新抗原特异性CD4 T细胞反应的功能多样性提供了前所未有的见解，并展示了免疫治疗干预如何影响抗肿瘤免疫反应的表型、强度和疗效。这些信息可能会在检查点阻断免疫疗法和癌症疫苗的临床环境中带来新的免疫监测方法。此外，我们表明Treg可以是TCR的有效来源，在ACT中可介导治疗益处。
