Waldman W J, Knight D A
Department of Pathology, Ohio State University College of Medicine, Columbus 43210-1238, USA.
Am J Pathol. 1996 Jan;148(1):105-19.
Cytomegalovirus (CMV) has been associated with allograft rejection and transplantation-associated arteriosclerosis. CMV infects endothelium, the interface between allograft tissue and the host immune system; however, mechanisms by which such interaction might exacerbate the rejection process remain unresolved. Here we test the hypothesis that host immune activity, triggered by CMV-infected graft endothelial cells (ECs), can result in the production of cytokines capable of enhancing the alloimmunogenicity of nearby uninfected endothelia. To model these phenomena in vitro, confluent monolayers of ECs derived from human umbilical vein or adult gonadal vein were incubated 5 days beneath trans-well culture inserts containing CMV-seropositive or CMV-seronegative donor-derived CD3+ or CD4+ T cells alone or in combination with CMV-infected or uninfected allogeneic ECs. The extent of T cell proliferation was determined by [3H]thymidine labeling of trans-well contents after transfer to microtiter plates. Endothelial responses to soluble factors elaborated by CMV-activated T cells were determined by immunohistochemical staining and immunofluorescence flow cytometric analysis of underlying EC monolayers. Results of experiments with CMV-seropositive donor-derived CD4+ T cells demonstrated enhancement of ICAM-1 and histocompatibility leukocyte antigen class I, as well as induction of histocompatibility leukocyte antigen DR on ECs incubated beneath T cell/EC/CMV trans-well co-cultures. Total (CD3+) T cells co-cultured with EC/CMV induced VCAM-1 as well. Furthermore, [3H]thymidine incorporation by these T cells indicated a strong proliferative response. Endothelial responses to T cells alone or in combination with uninfected ECs were minimal, and T cells cultured under these conditions showed little proliferative activity. Similarly, little or no endothelial responses were apparent in monolayers beneath trans-wells containing T cells isolated from CMV-seronegative individuals regardless of the CMV status of stimulator ECs. Finally, experiments employing blocking antibodies identified interferon-gamma and tumor necrosis factor-alpha as inducing agents in this co-culture system. These findings suggest that allograft endothelium harboring CMV has the potential to activate host T cells and that the consequent release of cytokines shows potential to raise surrounding endothelia to a fully activated, highly immunogenic state. Results of these studies thus provide insight into mechanisms that help elucidate the association between CMV and transplantation-associated arteriosclerosis and/or allograft rejection.
巨细胞病毒（CMV）与同种异体移植排斥反应及移植相关的动脉硬化有关。CMV感染内皮细胞，而内皮细胞是同种异体移植组织与宿主免疫系统之间的界面；然而，这种相互作用可能加剧排斥反应的机制仍未明确。在此，我们检验了这样一个假设：由CMV感染的移植内皮细胞（ECs）触发的宿主免疫活性，可导致细胞因子的产生，这些细胞因子能够增强附近未感染内皮细胞的同种免疫原性。为了在体外模拟这些现象，将源自人脐静脉或成人性腺静脉的内皮细胞汇合单层培养物，在含有CMV血清阳性或CMV血清阴性供体来源的CD3+或CD4+ T细胞单独或与CMV感染或未感染的同种异体ECs的跨孔培养插入物下方孵育5天。通过将跨孔内容物转移至微量滴定板后用[3H]胸腺嘧啶核苷标记来确定T细胞增殖程度。通过对下层EC单层进行免疫组织化学染色和免疫荧光流式细胞术分析，来确定内皮细胞对CMV激活的T细胞所产生的可溶性因子的反应。用CMV血清阳性供体来源的CD4+ T细胞进行的实验结果表明，在T细胞/EC/CMV跨孔共培养物下方孵育的ECs上，细胞间黏附分子-1（ICAM-1）和组织相容性白细胞抗原I类增强，以及组织相容性白细胞抗原DR诱导。与EC/CMV共培养的总（CD3+）T细胞也诱导了血管细胞黏附分子-1（VCAM-1）。此外，这些T细胞的[3H]胸腺嘧啶核苷掺入表明有强烈的增殖反应。内皮细胞对单独的T细胞或与未感染的ECs组合的反应最小，并且在这些条件下培养的T细胞显示出很少的增殖活性。同样，在含有从CMV血清阴性个体分离的T细胞的跨孔下方的单层中，无论刺激ECs的CMV状态如何，几乎没有或没有明显的内皮细胞反应。最后，使用阻断抗体的实验确定干扰素-γ和肿瘤坏死因子-α是该共培养系统中的诱导剂。这些发现表明，携带CMV的同种异体移植内皮细胞有激活宿主T细胞的潜力，并且随之释放的细胞因子显示出将周围内皮细胞提升至完全激活的、高度免疫原性状态的潜力。因此，这些研究结果为有助于阐明CMV与移植相关的动脉硬化和/或同种异体移植排斥反应之间关联的机制提供了见解。
