Establishment of Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA)-positive nasopharyngeal carcinoma hybrid cell line (NPC-KT)

Summary Primary nasopharyngeal carcinoma (NPC) cells were fused to hypoxanthine-guanine phosphoribosyltransferase (HGPRT)-defective cells derived from adenoid tissues using Sendai virus. Some of the fused cells developed into epithelial-like hybrid cells in a selective HAT medium. The hybrid cells (NPC-KT) were Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA)-positive cells. There have been no reports on the establishment of EBNA-positive epithelial cell lines derived from NPC. Thus, the epithelial-like hybrid cells might serve as an in vitro model for studying the biologic activity of NPC-associated EBV.     

Establishment of Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA)-positive nasopharyngeal carcinoma hybrid cell line (NPC-KT)

Primary nasopharyngeal carcinoma (NPC) cells were fused to hypoxanthine-guanine phosphoribosyltransferase (HGPRT)-defective cells derived from adenoid tissues using Sendai virus. Some of the fused cells developed into epithelial-like hybrid cells in a selective HAT medium. The hybrid cells (NPC-KT) were Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA)-positive cells. There have been no reports on the establishment of EBNA-positive epithelial cell lines derived from NPC. Thus, the epithelial-like hybrid cells might serve as an in vitro model for studying the biologic activity of NPC-associated EBV.     

Epstein-Barr virus (EBV) receptors on epithelial hybrid cells derived from nasopharyngeal carcinoma

We previously established an Epstein-Barr virus (EBV) genome-positive epithelial hybrid cell line, designated NPC-KT, which was prepared by fusing primary epithelial cells derived from nasopharyngeal carcinoma (NPC) with an epithelial Ad-AH cell line. In this study, we measured the presence of the EBV receptors using radiolabelled EBV. It was determined that similar amounts of Burkitt's lymphoma (BL)-derived P3HR-1 or NPC-KT-derived EBV can attach BL-derived Raji cells, but that only P3HR-1 virus can attach to NPC-KT cells. In addition, the superinfection of NPC-KT cells with P3HR-1 virus could not be inhibited by pretreatment with a monoclonal antibody against C3d (OKB7). Raji cells adsorbed with OKB7 became much less susceptible to superinfection with P3HR-1 or NPC virus. The data suggest that EBV receptors unrelated to C3d receptor exist.     

Establishment of Epstein-Barr virus (EBV) infection in epithelial cells derived from the nasopharynx by cell fusion

To establish EBV-infection in the nasopharyngeal epithelial cells, we carried out cell fusion of the lymphocytes with nasopharyngeal epithelial cells, and proved that it was possible to detect the appearance of EBNA in the epithelial nuclei. It is suggested that the establishment of EBV-infection in nasopharyngeal epithelial cells may include cell fusion and involvement of the EBV receptors.     

Neck lymph node metastases of unknown origin: nasopharyngeal origin and EBV (Epstein-Barr virus)

We present a retrospective series of 16 cases of undifferentiated squamous carcinoma in cervical metastatic nodes of unknown primary. We review their clinical and radiological evaluation in search of a possible primary tumor, their response to treatment and the eventual development of a primary tumor. Furthermore, we study the presence of Epstein-Barr virus in the metastases as a predictor of their nasopharyngeal origin, in relation to the finding of primary lesions in the nasopharynx during further follow-up of the cases.     

The difference in tumorigenicity between Epstein-Barr virus (EBV) genome-positive and genome-negative epithelial hybrid cell lines derived from the human nasopharynx

An epithelial/hybrid cell line was previously established (A2L/AH) by the fusion of 8-azaguanine-resistant epithelial cells (Ad-AH) with Epstein-Barr virus (EBV)-transformed lymphoblastoid cells (A2L), as a nasopharyngeal carcinoma (NPC) model cell line in vitro. However, the A2L/AH cells were nontumorigenic in nude mice during early passage levels. In this study, an EBV genome-negative clone and two EBV genome-positive clones of the A2L/AH cells have been successfully cloned. We have continued to culture these three clones, as it is possible that EBV may disturb mechanisms that regulate tumorigenicity when cells are grown in vitro for long periods of time. Two EBV genome-positive A2L/AH clones have become tumorigenic in nude mice after long periods in culture, whereas EBV genome-negative A2L/AH cells were nontumorigenic after the same period of time. The data suggest that EBV may be associated with tumorigenicity in nude mice, at least in part.     

Epstein-Barr virus (EBV) infection by cocultivation of fibroblast-dominant cell line and EBV-transformed lymphocytes

A long-term cell culture epitheloid cell line (NPC-F/L) was established from the fibroblast-dominant cell line derived from nasopharyngeal carcinoma tissue by cocultivation with an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line of adenoid origin. The cells were investigated by karyotyping, by immunofluorescent testing for EBV-associated nuclear antigen (EBNA), early antigen (EA), and viral capsid antigen (VCA) and by a light microscopy. The cells were shown to be epithelial not only by morphology but also by immunocytochemical staining with monoclonal antibody to cytokeratins and they expressed EBNA and EA but not VCA. The cells developed histologically undifferentiated squamous cell carcinoma when inoculated subcutaneously into the back of athymic nude BALB/c(nu/nu) mice, which were similar to the human tumors from which the fibroblastoid cell line was established. The presence of EBNA in touch smears prepared both from the biopsy tissue of human and nude mice was demonstrated. Karyotyping analysis indicated an aneuploid chromosome with a model number of 74.     

CK13基因与EB病毒DNA在鼻咽癌中的表达及临床意义

目的 探讨细胞角蛋白基因13（CK13）和EB病毒DNA在人鼻咽癌（NPC）组织中的表达及意义。方法 应用Northern杂交对32例NPC和8例慢性鼻咽炎（CINE）组织进行CK13mRNA水平检测,同时应用PCR方法进行EB病毒DNA检测。结果 ＣＫ１３基因在鼻咽炎组织中高表达,在ＮＰＣ组织中的表达显著下调。下调的频率达６５.63%(21/32)。结论 ＮＰＣ组织的分化可能与ＣＫ１３基因的表达下调有关。     

Primary EBV infection of human umbilical cord lymphocytes and EBV genome-negative lymphoblastoid cell lines (BJAB and Ramos)

The appearance of Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) and induction of EBV-induced early antigen (EA) in human umbilical cord blood lymphocytes (HUCLs) and two EBV genome-negative Burkitt's lymphoma (BL) lines (BJAB and Ramos) were studied by infection with EBVs prepared from three different cell lines: marmoset cell line (B95-8) derived from infections mononucleosis, BL-derived cell line (P3HR-1) and human epithelial hybrid cell line (NPC-KT) derived from nasopharyngeal carcinoma. B95-8 virus can transform HUCLs but cannot superinfect Raji cells. P3HR-1 virus can transform HUCLs cells but cannot transform HUCLs. NPC-KT virus can transform HUCLs and can superinfect Raji cells. We have examined the time sequence of EBNA appearance and EA induction in HUCLs, BJAB cells and Ramos cells, in order to determine if three different strains of EBV differ in their abilities to infect their cells. We found that all three strains of EBV can induce EBNA in HUCLs, BJAB cells and Ramos cells. On the other hand, we found that P3HR-1 virus and NPC-KT virus can induce EA in BJAB cells and Ramos cells, but B95-8 virus cannot induce EA in their cells.     

鼻咽癌患者鼻咽组织和血清中EBV检测

目的：比较血清爱泼斯坦－巴尔病毒（ＥＢＶ）抗体滴定度测定与癌组织ＥＢＶ基因组检测对鼻咽癌（ＮＰＣ）的诊断价值。方法：１４６例患者采用双盲法测定血清ＥＢＶ－ＶＣＡ－ＩｇＡ,ＥＢＶ－ＥＡ－ＩｇＡ和活检组织ＥＢＶ－ＤＮＡ（ＰＣＲ）。全组病例按活检病理检查结果分析：ＮＰＣ组,非ＮＰＣ组（对照组）。结果：ＮＰＣ组中ＥＢＶ－ＤＮＡ（ＰＣＲ）,ＥＢＶ－ＶＣＡ－ＩｇＡ和ＥＢＶ－ＥＡ－ＩｇＡ的阳性率分别为９０．８％     

The role of fibreoptic nasopharyngoscopy in nasopharyngeal carcinoma (NPC)

With the introduction of the flexible fibreoptic nasopharyngo-laryngoscope, we have a sophisticated instrument for examination of the nasopharynx and larynx. It is also useful for obtaining biopsies from the nasopharynx and has many advantages over other methods. The most important is that it is possible to take biopsies from selected sites under direct visualization and the biopsy results are therefore more reliable.     

Experimental studies on specific immunotherapy in nasopharyngeal carcinoma (NPC)

Summary The IgG fraction was isolated from the serum of patients with nasopharyngeal carcinoma and conjugated with ferritin or horseradish peroxidase. The conjugate was injected i.v. in nude mice on which transplanted nasopharyngeal carcinomas were growing. Electron-microscopic examination of the tissue revealed localization of the antibodies of the IgG class (VCA, EBNA) exclusively within the tumor cell association of NPC transplants, mainly on the outer cell membrane, on mitochondria of the cytoplasm, and on the membranes of the endoplasmic reticulum. The possibility of conjugating such EBV-specific and thus NPC tumor cell-related antibodies with cytostatically active substances so as to convey the cytostatics directly to the tumor cells is discussed.Supported by the Deutsche Forschungsgemeinschaft