INSERM UMR-S-1172, Centre de Recherche Jean-Pierre Aubert (JPARC), France; Institut pour la Recherche sur le Cancer de Lille (IRCL), 1, place de verdun, 59045 Lille Cedex, France.
Institut pour la Recherche sur le Cancer de Lille (IRCL), 1, place de verdun, 59045 Lille Cedex, France; IFR 114, IMPRT, Institut de Médecine Prédictive et de Recherche Thérapeutique, plate-forme génomique fonctionnelle et structurale, France; Université de Lille, Lille, France.
Immunol Lett. 2017 Dec;192:27-34. doi: 10.1016/j.imlet.2017.10.004. Epub 2017 Oct 10.
In acute myeloid leukaemia (AML)-affected patients, the presence of heterogeneous sub-clones at diagnosis has been shown to be responsible for minimal residual disease and relapses. The role played by the immune system in this leukaemic sub-clonal hierarchy and maintenance remains unknown. As leukaemic sub-clone immunogenicity could not be evaluated in human AML xenograft models, we assessed the sub-clonal diversity of the murine C1498 AML cell line and the immunogenicity of its sub-clones in immune-competent syngeneic mice.
The murine C1498 cell line was cultured in vitro and sub-clonal cells were generated after limiting dilution. The genomic profiles of 6 different sub-clones were analysed by comparative genomic hybridization arrays (CGH). The sub-clones were then injected into immune-deficient and - competent syngeneic mice. The immunogenicities of the sub-clones was evaluated through 1) assessment of mouse survival, 2) determination of leukaemic cell infiltration into organs by flow cytometry and the expression of a fluorescent reporter gene, 3) assessment of the CTL response ex vivo and 4) detection of residual leukaemic cells in the organs via amplification of the genomic reporter gene by real-time PCR (qPCR).
Genomic analyses revealed heterogeneity among the parental cell line and its derived sub-clones. When injected individually into immune-deficient mice, all sub-clones induced cases of AML with different kinetics. However, when administered into immune-competent animals, some sub-clones triggered AML in which no mice survived, whereas others elicited reduced lethality rates. The AML-surviving mice presented efficient anti-leukaemia CTL activity ex vivo and eliminated the leukaemic cells in vivo.
We showed that C1498 cell sub-clones presented genomic heterogeneity and differential immunogenicity resulting either in immune escape or elimination. Such findings could have potent implications for new immunotherapeutic strategies in patients with AML.
在急性髓系白血病（AML）患者中，诊断时存在异质性亚克隆被认为是导致微小残留病和复发的原因。免疫系统在白血病亚克隆层次结构和维持中的作用尚不清楚。由于无法在人类 AML 异种移植模型中评估白血病亚克隆的免疫原性，我们评估了免疫活性的同基因小鼠中鼠 C1498 AML 细胞系的亚克隆多样性及其亚克隆的免疫原性。
将鼠 C1498 细胞系在体外培养，并通过有限稀释生成亚克隆细胞。通过比较基因组杂交阵列（CGH）分析 6 个不同亚克隆的基因组图谱。然后将亚克隆注入免疫缺陷和免疫活性的同基因小鼠。通过以下方法评估亚克隆的免疫原性：1）评估小鼠的存活率，2）通过流式细胞术确定白血病细胞浸润器官的情况和荧光报告基因的表达，3）评估 CTL 反应的体外情况，4）通过实时 PCR（qPCR）检测器官中残留的白血病细胞扩增。
基因组分析显示亲本细胞系及其衍生的亚克隆之间存在异质性。当单独注入免疫缺陷小鼠时，所有亚克隆均以不同的动力学诱导 AML。然而，当注入免疫活性动物时，一些亚克隆引发的 AML 中没有小鼠存活，而其他亚克隆则引发较低的致死率。AML 存活的小鼠具有有效的抗白血病 CTL 活性，并能在体内消除白血病细胞。
我们表明 C1498 细胞亚克隆具有基因组异质性和不同的免疫原性，导致免疫逃逸或消除。这些发现可能对 AML 患者的新免疫治疗策略产生重大影响。
