Mizukami Yoshihisa, Abe Tomoyuki, Shibata Hiroaki, Makimura Yukitoshi, Fujishiro Shuh-hei, Yanase Kimihide, Hishikawa Shuji, Kobayashi Eiji, Hanazono Yutaka
Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan.
Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; Center for Development of Advanced Medical Technology, Jichi Medical University, Tochigi, Japan.
PLoS One. 2014 Jun 13;9(6):e98319. doi: 10.1371/journal.pone.0098319. eCollection 2014.
Recent studies have revealed negligible immunogenicity of induced pluripotent stem (iPS) cells in syngeneic mice and in autologous monkeys. Therefore, human iPS cells would not elicit immune responses in the autologous setting. However, given that human leukocyte antigen (HLA)-matched allogeneic iPS cells would likely be used for medical applications, a more faithful model system is needed to reflect HLA-matched allogeneic settings. Here we examined whether iPS cells induce immune responses in the swine leukocyte antigen (SLA)-matched setting. iPS cells were generated from the SLA-defined C1 strain of Clawn miniature swine, which were confirmed to develop teratomas in mice, and transplanted into the testes (n = 4) and ovary (n = 1) of C1 pigs. No teratomas were found in pigs on 47 to 125 days after transplantation. A Mixed lymphocyte reaction revealed that T-cell responses to the transplanted MHC-matched (C1) iPS cells were significantly lower compared to allogeneic cells. The humoral immune responses were also attenuated in the C1-to-C1 setting. More importantly, even MHC-matched iPS cells were susceptible to innate immunity, NK cells and serum complement. iPS cells lacked the expression of SLA class I and sialic acids. The in vitro cytotoxic assay showed that C1 iPS cells were targeted by NK cells and serum complement of C1. In vivo, the C1 iPS cells developed larger teratomas in NK-deficient NOG (T-B-NK-) mice (n = 10) than in NK-competent NOD/SCID (T-B-NK+) mice (n = 8) (p<0.01). In addition, C1 iPS cell failed to form teratomas after incubation with the porcine complement-active serum. Taken together, MHC-matched iPS cells can attenuate cellular and humoral immune responses, but still susceptible to innate immunity in pigs.
近期研究表明，诱导多能干细胞（iPS细胞）在同基因小鼠和自体猴子体内的免疫原性可忽略不计。因此，人iPS细胞在自体环境中不会引发免疫反应。然而，鉴于人类白细胞抗原（HLA）匹配的同种异体iPS细胞可能会用于医学应用，需要一个更可靠的模型系统来反映HLA匹配的同种异体环境。在此，我们研究了iPS细胞在猪白细胞抗原（SLA）匹配的环境中是否会诱导免疫反应。iPS细胞由SLA定义的克劳恩小型猪C1品系产生，经证实其在小鼠体内可形成畸胎瘤，并被移植到C1猪的睾丸（n = 4）和卵巢（n = 1）中。移植后47至125天，在猪体内未发现畸胎瘤。混合淋巴细胞反应显示，与异基因细胞相比，T细胞对移植的MHC匹配（C1）iPS细胞的反应显著降低。在C1到C1的环境中，体液免疫反应也减弱。更重要的是，即使是MHC匹配的iPS细胞也易受先天免疫、自然杀伤细胞（NK细胞）和血清补体的影响。iPS细胞缺乏SLA I类和唾液酸的表达。体外细胞毒性试验表明，C1 iPS细胞是C1的NK细胞和血清补体的靶标。在体内，C1 iPS细胞在NK缺陷的NOG（T - B - NK -）小鼠（n = 10）中形成的畸胎瘤比NK功能正常的NOD/SCID（T - B - NK +）小鼠（n = 8）中的更大（p<0.01）。此外，C1 iPS细胞与猪补体活性血清孵育后未能形成畸胎瘤。综上所述，MHC匹配的iPS细胞可减弱细胞免疫和体液免疫反应，但在猪体内仍易受先天免疫的影响。
