- 期刊
The Role of Epstein-Barr Virus Infection and the Immunocompetence of Patients with Nasopharyngeal Cancer
EB病毒的感染與鼻咽癌病人的免疫力
摘要
鼻咽癌患者血清中對EB病毒IgA滴度普遍升高，而且癌巢內及附近淋巴細胞浸潤大量增加。可是病人的免疫力卻反而衰退。 因為介白素十號(IL-10)有壓抑細胞性免疫反應（例如殺手細胞及吞噬細胞），卻提昇體液性免疫反應（例如抗體的產生）的作用，而EB病毒晚期基因BCRF 1與介白素十號有相似的基因序列（又稱vIL-10），也可能具有相似的功能。再者可溶性介白素二號受體(IL-2R)也可能壓抑細胞性免疫反應，因此，本文就針對這些EB病毒感染與鼻咽癌病人的免疫力等問題提出一些我們的看法，藉著分析與EB病毒有關的疾病，EB病毒的致癌機轉，細胞與病毒的相互作用，細胞培養的模式，病毒因素與其他致病因素的作用，進而討論病毒在癌細胞中究竟是潜伏性感染或是再激活感染，也由此探討病人免疫力的减弱和疾病的惡化。希望能由科學上的觀察幫助瞭解病人免疫力降低的可能原因，對臨床的現象有更好的解釋，幷爲未來的免疫治療、基因治療或免疫基因治療的設計，提供一個理論基礎。
並列摘要
Seral IgA titer to gene products of Epstein-Barr virus is prevalently elevated in patients with nasopharyngeal carcinoma, an indication of EBV infection. Pathologically, tumor infiltrating lymphocytes that could be attracted by the presence of EBY in the NPC cells also increased immensely in the neighborhood of tumor nest. In a glance, EBV seemed to induce both cellular and humoral immune response. However, the immunocompetence of patients inversely decreased following the progression of the disease. Interleukin-l0 (IL-l0), a potent cytokine synthesis inhibitory factor, suppresses function of T cells and NK cells ns well as that of monocytes and macrophages, the major components of cellular immune response. Besides its suppression on cellular immunity, IL-b stimulates B cells to enhance their viability, cell proliferation, class II MHC expression and immunoglobulin secretion, a hallmark of humoral immune response. Interestingly, sequence of a EBV late gene, UCIIF1, is highly homologous to that of both mouse and human IL-10(BCRF1 gene product is now designated as vIL-10). It may exert a similar function like that of JL-10. The activity of vIL-10 may explain the unusual seral phenomena and the aggregated non-functional lymphocytes surrounding the tumor nest. Anthor factor affecting the cellular immunity is the presence of soluble interleukin-2 receptor (sIL-2R) that will compete with the membrane-bound IL-2R and desensitize the immune response. With these leads, the authors will discuss the subject ”the role of Epstein-Barr virus infection and the immunocompetence of patients with nasopharyngeal cancer” in the following catogories: EBV-associated diseases and oncogenesis, virus-cell interaction, cell culture model, synergistic effect between viral and other risk factors, latent infection or the reactivated infection, and abrogation of immunocompetence and tumor progression. Hopefully, the discussion will delineate the plausible reason for the decreasing immunocompetence in patients with NPC and will provide a better explanation for the clinical phenomena as well as the theoretical base for the future design of immunotherapy, gene therapy and immuno-gene therapy.