Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
Rebirth Excellence Cluster and Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany.
Cytotherapy. 2016 Apr;18(4):570-80. doi: 10.1016/j.jcyt.2016.01.005.
Dendritic cell (DC)-tumor cell hybrids have been used clinically in cancer immunotherapy, but their advantage over the simple mixture of tumor cells and DCs is still a matter of controversy. In this study, we compared DC-tumor cell hybrids with the non-fused mixture of DC and tumor cells directly in their ability to induce a specific immune response.
Hybrids were obtained by electrofusion of tumor cells and monocyte-derived DCs. Cell phenotype was evaluated by flow cytometry and antigen-presenting ability by co-culture with syngeneic T cells followed by tetramer analysis and interferon (IFN)-γ ELISPOT.
Less than half the cells in the mixture expressed DC co-stimulatory molecules. Furthermore, DCs in the mixture had significantly lower expression of MHC class I molecules than DCs in the fusion. Conversely, nearly all CD11c(+)Her2/neu(+) hybrids expressed CD80, CD86, CD83, HLA-DR and MHC class I from both tumor cells and DCs. Using tumor cells constitutively expressing a cytomegalovirus (CMV) antigen, we show that expansion of CMV-specific cytotoxic T lymphocytes (CTLs) restricted by DCs' MHC class I molecules was higher when DC-tumor hybrids were the stimulators. Furthermore, only hybrids stimulated CTLs to produce IFN-γ in response to CMV-positive target cells.
These data show the superiority of DC-tumor cell hybrids over their simple mixture as T-cell stimulators. Hybrids expressed more co-stimulatory and MHC molecules, induced higher antigen-specific T-cell expansion and were the only cells able to induce IFN-γ-producing antigen-specific T cells. Thus, these data offer further support for cancer immunotherapeutic approaches using DC-tumor cell hybrids.
树突状细胞（DC）-肿瘤细胞杂交体已在癌症免疫治疗中临床应用，但它们比肿瘤细胞和 DC 简单混合物的优势仍存在争议。在这项研究中，我们比较了 DC-肿瘤细胞杂交体与直接混合的 DC 和肿瘤细胞在诱导特异性免疫反应方面的能力。
通过电融合肿瘤细胞和单核细胞衍生的 DC 获得杂交体。通过与同种 T 细胞共培养进行细胞表型评估，并通过四聚体分析和干扰素（IFN）-γ ELISPOT 评估抗原呈递能力。
混合物中只有不到一半的细胞表达 DC 共刺激分子。此外，混合物中的 DC 表达 MHC Ⅰ类分子的水平明显低于融合中的 DC。相反，几乎所有 CD11c（+）Her2/neu（+）杂交体都表达来自肿瘤细胞和 DC 的 CD80、CD86、CD83、HLA-DR 和 MHC Ⅰ类分子。使用持续表达巨细胞病毒（CMV）抗原的肿瘤细胞，我们表明，当 DC-肿瘤杂交体作为刺激物时，CMV 特异性细胞毒性 T 淋巴细胞（CTL）的扩展受到 DC MHC Ⅰ类分子限制的更高。此外，只有杂交体刺激 CTL 产生 IFN-γ，以响应 CMV 阳性靶细胞。
这些数据表明，DC-肿瘤细胞杂交体作为 T 细胞刺激物优于其简单混合物。杂交体表达更多的共刺激和 MHC 分子，诱导更高的抗原特异性 T 细胞扩增，并且是唯一能够诱导 IFN-γ 产生的抗原特异性 T 细胞的细胞。因此，这些数据为使用 DC-肿瘤细胞杂交体的癌症免疫治疗方法提供了进一步的支持。
