Scancell Ltd, University of Nottingham Biodiscovery Institute, Nottingham, UK.
Biodiscovery Institute, University of Nottingham Faculty of Medicine and Health Sciences, Nottingham, UK.
J Immunother Cancer. 2020 Jun;8(1). doi: 10.1136/jitc-2020-000560.
Stress-induced post-translational modifications occur during autophagy and can result in generation of new epitopes and immune recognition. One such modification is the conversion of arginine to citrulline by peptidylarginine deiminase enzymes.
We used Human leukocyte antigen (HLA) transgenic mouse models to assess the immunogenicity of citrullinated peptide vaccine by cytokine Enzyme linked immunosorbant spot (ELISpot) assay. Vaccine efficacy was assessed in tumor therapy studies using HLA-matched B16 melanoma and ID8 ovarian models expressing either constitutive or interferon-gamma (IFNγ) inducible Major Histocompatibility Complex (MHC) class II (MHC-II) as represented by most human tumors. To determine the importance of CD4 T cells in tumor therapy, we analyzed the immune cell infiltrate into murine tumors using flow cytometry and performed therapy studies in the presence of CD4 and CD8 T cell depletion. We assessed the T cell repertoire to citrullinated peptides in ovarian cancer patients and healthy donors using flow cytometry.
The combination of citrullinated vimentin and enolase peptides (Modi-1) stimulated strong CD4 T cell responses in mice. Responses resulted in a potent anti-tumor therapy against established tumors and generated immunological memory which protected against tumor rechallenge. Depletion of CD4, but not CD8 T cells, abrogated the primary anti-tumor response as well as the memory response to tumor rechallenge. This was further reinforced by successful tumor regression being associated with an increase in tumor-infiltrating CD4 T cells and a reduction in tumor-associated myeloid suppressor cells. The anti-tumor response also relied on direct CD4 T cell recognition as only tumors expressing MHC-II were rejected. A comparison of different Toll-like receptor (TLR)-stimulating adjuvants showed that Modi-1 induced strong Th1 responses when combined with granulocyte-macrophage colony-stimulating factor (GMCSF), TLR9/TLR4, TLR9, TLR3, TLR1/2 and TLR7 agonists. Direct linkage of the TLR1/2 agonist to the peptides allowed the vaccine dose to be reduced by 10-fold to 100-fold without loss of anti-tumor activity. Furthermore, a CD4 Th1 response to the citrullinated peptides was seen in ovarian cancer patients.
Modi-1 citrullinated peptide vaccine induces potent CD4-mediated anti-tumor responses in mouse models and a CD4 T cell repertoire is present in ovarian cancer patients to the citrullinated peptides suggesting that Modi-1 could be an effective vaccine for ovarian cancer patients.
自噬过程中会发生应激诱导的翻译后修饰，从而产生新的表位和免疫识别。这样的修饰之一是由肽基精氨酸脱亚氨酶酶将精氨酸转化为瓜氨酸。
我们使用人类白细胞抗原（HLA）转基因小鼠模型，通过细胞因子酶联免疫斑点（ELISpot）测定评估瓜氨酸化肽疫苗的免疫原性。在使用 HLA 匹配的 B16 黑色素瘤和 ID8 卵巢模型的肿瘤治疗研究中评估疫苗功效，这些模型表达组成型或干扰素-γ（IFNγ）诱导的主要组织相容性复合物（MHC）II 类（MHC-II），代表大多数人类肿瘤。为了确定 CD4 T 细胞在肿瘤治疗中的重要性，我们使用流式细胞术分析了小鼠肿瘤中的免疫细胞浸润，并在 CD4 和 CD8 T 细胞耗竭的情况下进行了治疗研究。我们使用流式细胞术评估了卵巢癌患者和健康供体对瓜氨酸化肽的 T 细胞反应。
瓜氨酸化波形蛋白和烯醇化酶肽（Modi-1）的组合在小鼠中刺激了强烈的 CD4 T 细胞反应。这些反应导致对已建立的肿瘤具有强大的抗肿瘤治疗作用，并产生了免疫记忆，可防止肿瘤再挑战。CD4 而非 CD8 T 细胞的耗竭消除了对肿瘤再挑战的原发性抗肿瘤反应和记忆反应。这进一步得到了成功的肿瘤消退的支持，肿瘤浸润性 CD4 T 细胞增加，肿瘤相关髓系抑制细胞减少。抗肿瘤反应还依赖于直接的 CD4 T 细胞识别，因为只有表达 MHC-II 的肿瘤才被排斥。比较不同的 Toll 样受体（TLR）刺激佐剂表明，当与粒细胞-巨噬细胞集落刺激因子（GMCSF）、TLR9/TLR4、TLR9、TLR3、TLR1/2 和 TLR7 激动剂联合使用时，Modi-1 诱导强烈的 Th1 反应。TLR1/2 激动剂与肽的直接连接允许将疫苗剂量减少 10 倍至 100 倍，而不会丧失抗肿瘤活性。此外，卵巢癌患者中存在针对瓜氨酸化肽的 CD4 Th1 反应。
Modi-1 瓜氨酸化肽疫苗在小鼠模型中诱导强烈的 CD4 介导的抗肿瘤反应，并且卵巢癌患者中存在针对瓜氨酸化肽的 CD4 T 细胞反应 repertoire，提示 Modi-1 可能是卵巢癌患者的有效疫苗。
