Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
Transplantation Center, Seoul National University Hospital, Seoul, Republic of Korea.
Transplantation. 2018 Mar;102(3):406-416. doi: 10.1097/TP.0000000000001966.
Macrophages play important roles in xenograft rejection. Here, we investigated whether overexpression of human CD200 or CD47 in porcine endothelial cells (PEC) can suppress macrophages activation in xenogeneic immune responses.
PECs and human macrophages were incubated together, harvested, and analyzed for in vitro macrophage phagocytic and cytotoxicity activity, and cytokine release. Next, PECs were injected into renal subcapsular space of humanized mice. On day 10 posttransplantation, we analyzed xenograft survival and perigraft inflammatory cell infiltrations in PEC-to-humanized mouse transplantation.
PECs highly expressing human CD200, CD47, or both CD47/CD200 were established by lentiviral vector transduction. Both CD200 and CD47 suppressed in vitro macrophage phagocytic and cytotoxic activity against PECs; decreased TNF-α, IL-1β, and IL-6 secretion; and increased IL-10 secretion. However, simultaneous overexpression of CD200 and CD47 did not show additive effects. Next, PECs were transplanted into NOD-scid IL-2Rg null mice, and human monocytes and lymphocytes were adoptively transferred 1 day after xenotransplantation. PEC xenograft cell death and apoptosis were decreased in the CD200-PEC and CD47/CD200-PEC groups. Perigraft infiltration of human T cells was suppressed by CD47; CD200 suppressed infiltration of human macrophages to a greater extent than CD47; and the CD47/CD200-PEC group exhibited the lowest level of leukocyte infiltration. In summary, overexpression of CD200 in PECs suppressed xenogeneic activation of human macrophages and improved survival of PEC xenografts in humanized mice; however, coexpression of CD200 and CD47 did not show additive effects.
Therefore, overexpression of human CD200 in donor pigs could constitute a promising strategy for overcoming xenograft rejection.
巨噬细胞在异种移植物排斥中发挥重要作用。在这里，我们研究了在猪内皮细胞（PEC）中超表达人 CD200 或 CD47 是否可以抑制异种免疫反应中巨噬细胞的激活。
将 PEC 和人巨噬细胞一起孵育，收获并分析体外巨噬细胞吞噬和细胞毒性活性以及细胞因子释放。然后，将 PEC 注射到人源化小鼠的肾被膜下空间。移植后第 10 天，分析 PEC 与人源化小鼠移植中的异种移植物存活和移植周围炎症细胞浸润。
通过慢病毒载体转导建立了高表达人 CD200、CD47 或两者的 PEC。CD200 和 CD47 均抑制体外巨噬细胞对 PEC 的吞噬和细胞毒性作用；减少 TNF-α、IL-1β 和 IL-6 的分泌；并增加 IL-10 的分泌。然而，同时过表达 CD200 和 CD47 并没有表现出相加效应。接下来，将 PEC 移植到 NOD-scid IL-2Rg null 小鼠中，在异种移植后 1 天过继转移人单核细胞和淋巴细胞。在 CD200-PEC 和 CD47/CD200-PEC 组中，PEC 异种移植物细胞死亡和凋亡减少。CD47 抑制了移植周围人类 T 细胞的浸润；CD200 对人类巨噬细胞的浸润抑制作用大于 CD47；而 CD47/CD200-PEC 组表现出最低水平的白细胞浸润。总之，在 PEC 中超表达 CD200 抑制了人类巨噬细胞的异种激活，并提高了人源化小鼠中 PEC 异种移植物的存活率；然而，CD200 和 CD47 的共表达并没有表现出相加效应。
因此，在供体猪中超表达人 CD200 可能是克服异种移植排斥的一种有前途的策略。
