Epstein-Barr virus infection and its gene expression in gastric lymphoma of mucosa-associated lymphoid tissue

The role of Epstein-Barr virus (EBV) in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) has not been well understood. The aim of the study was to investigate EBV infection and its gene expression in this tumor in order to understand its role in the pathogenesis. EBV infection was screened by in situ hybridization for EBV-encoded nonpolyadenylated RNA (EBER ISH) in 79 cases of gastric MALT lymphoma of nonimmunocompromised patients. The expression of EBV proteins [LMP1 (latent membrane protein 1), EBNA2 (EBV nuclear antigen 2), ZEBRA (switch protein encoded by BZLF1 gene)] was studied by immunohistochemistry in EBER-positive cases. EBV was detected with EBER ISH in 15 (19%) of the 79 cases. EBV was found in virtually all tumor cells in 2 cases of high-grade MALT lymphoma (2.5%) (EBV-associated), and was found only in occasional large or small lymphoid cells in 13 cases (16.5%). False positive EBER signal was detected in the mucinous glandular epithelial cells of gastric antrum with FITC-labeled oligonucleotide probe but not with digoxigenin or ³⁵S-labeled riboprobes. Type II latency (EBER+LMP1+ EBNA2-) was detected in both EBV-associated cases. Type III latency (EBER+LMP1+EBNA2+) was also identified in one EBV-associated case besides latency II. Double labeling showed coexpression of LMP1 and EBNA2 in a small number of tumor cells, indicating the presence of type III latency in single cell level. In cases with only occasional EBER-positive large or small lymphoid cells, LMP1 and EBNA2 were not detected. ZEBRA was negative in all the cases. These findings suggest that EBV may contribute to the pathogenesis of a small proportion of high-grade MALT lymphoma, where virtually all tumor cells harbored EBV and the oncogenic viral protein LMP1 was expressed. Moreover, latency III of EBV infection may exist in nonimmunocompromised patient. J. Med. Virol. 56:342–350, 1998 . © 1998 Wiley-Liss, Inc.     

Clinical characteristics of primary and reactivated Epstein-Barr virus infection in children

Epstein-Barr virus (EBV) infection occurs commonly in children and presents as a primary or reactivated infection, which are difficult for clinicians to distinguish. This study investigated the clinical characteristics of the two types of infections. Children with detectable plasma EBV-DNA were retrospectively enrolled and divided into primary and reactivated infection group by EBV-specific antibody. We analyzed the patients' characteristics, clinical manifestations, complications, inflammatory biomarkers, and viral load. A total of 9.3% of children with reactivation were immunocompromised over the long-term. The primary infection mostly appeared as infectious mononucleosis (99.8%), while reactivation occurred as an infectious mononucleosis-like disease (65.0%), hemophagocytic syndrome (22.6%), chronic active EBV infection (5.3%) and lymphoma (3.5%). The incidence of fevers, cervical lymphoditis, periorbital edema, pharyngotonsillitis, hepatomegaly and splenomegaly in primary infection were 93.3%, 93.0%, 51.5%, 66.0%, 76.2% and 63.9%, respectively; the incidence of those symptoms in reactivation was 84.0%, 46.9%, 15.4%, 18.5%, 18.5%, and 43.3%, respectively. The incidence of digestive, respiratory, cardiovascular, neurological, hematological, genitourinary complications and multiple serous effusion in primary infection was 68.8%, 18.1%, 8.0%, 0.8%, 2.9%, 0.0% and 2.3%; whereas the incidence of these complications in reactivation was 56.2%, 22.5%, 14.1%, 8.0%, 38.9%, 0.3% and 19.0%. Patients with reactivation were more prone to multi-systemic damage. B-cells were lower, and CD8+ T-cells were higher in primary infection. Viral load was correlated with the level of different cytokines in primary and reactivated infection. EBV primary infection often presents as infectious mononucleosis. The reactivated infection affects more immunocompromised subjects with diverse and complex manifestations. Various complications are more commonly associated with reactivation as a result of different inflammatory responses to different types of infection.     

地塞米松对SUNE-1和B95-8细胞株中EB病毒BHRF1基因转录水平的影响

目的：以Ｋ５６２细胞为阴性对照,观察ＳＵＮＥ－１和Ｂ９５８两种含ＥＢＶ－ＢＨＲＦ１基因的肿瘤细胞株在２×１０６ｍｏｌ／Ｌ地塞米松（ｄｅｘａｍｅｔｈａｓｏｎｅ,ＤＥＸ）作用１８ｈ后,细胞内ＥＢＶ－ＢＨＲＦ１基因转录水平的改变。方法：细胞ＲＮＡ的提取、ＲＮＡ的点杂交（Ｄｏｔｂｌｏｔ）及反转录ＰＣＲ（ＲＴ－ＰＣＲ）。结果：上述两种肿瘤细胞在２×１０６ｍｏｌ／Ｌ地塞米松作用１８ｈ等诱导细胞凋亡的条件下,细胞内ＥＢＶ－ＢＨＲＦ１基因的转录水平（ｍＲＮＡ）明显提高。结论：本结果初步显示ＥＢＶ－ＢＨＲＦ１基因的转录与宿主细胞抵抗凋亡的关系密切。     

Heterogeneity of Epstein-Barr virus infection in angioimmunoblastic lymphadenopathy type T-cell lymphoma

To investigate the relationship of Epstein-Barr virus (EBV) and angioimmunoblastic lymphadenopathy with dysproteinemia, we performed DNA analysis using the polymerase chain reaction (PCR), Southern blot, in situ hybridization, and immunohistochemical analysis of lymph nodes in five patients who were followed up and biopsied more than once. In the course of the disease, nodal architecture diminished, cellular atypia worsened, and clear cells increased in number. In the DNA analysis of the receptor genes, the clonal population increased in number. EBV nucleic acid sequences were found by either PCR or in situ hybridization in all examined nodes. The number of EBV-positive cells varied widely among the cases and throughout the course of the disease in the same patients. The analysis of EBV terminal repeats or lymphocyte-determined membrane antigen genes showed polyclonal populations of EB-infected cells. EBV-positive cells possessed intermediate- to large-sized nuclei, and the cells with large nuclei, especially, expressed latent membrane protein of EBV. These large cells varied in number among the cases. Double-labelling immunohistochemistry/in situ hybridization studies demonstrated that most of the EBV-positive cells expressed B-cell antigen (CD20). The presence of EBV seems to be associated with the selective defects of the immune system, rather than with the direct pathogenesis of angioimmunoblastic lymphadenopathy.     

The evolution of Epstein-Barr virus inferred from the conservation and mutation of the virus glycoprotein gp350/220 gene

To study variations of Epstein-Barr virus (EBV), we analyzed the gp350/220 gene for several cell lines and Japanese wild isolates using direct sequencing. The N-terminal region was highly conserved in all EBVs except for Jijoye/P3HR-1 and a few isolates. The variation of the region coincided with EBV types A and B (also referred to as types 1 and 2) and were, respectively, designated as the types a and b. The type A/a was detected in most Japanese cell lines and wild isolates, and was classified as China1 type with latent membrane protein (LMP) 1 gene. The type B/b was detected in only a few wild isolates with the Med and China2 types. The C-terminus had more diversity than the N-terminus and lacked the divergence between types A/a and B/b. The phylogenetic analyses of the gp350/220 and LMP1 genes may suggest a mode of EBV evolution into types A/a and B/b and then to LMP1 subtypes.     

A membrane-located glycosphingolipid of monocyte/granulocyte lineage cells induces growth arrest and triggers the lytic viral cycle in Epstein-Barr virus genome-positive Burkitt lymphoma lines

Gangliosides are known to influence cell growth and differentiation. The neolacto series ganglioside IV³NeuAc-nLc₄ (2→3-sialosylparagloboside) is present in members of the monocyte/granulocyte lineage, but is not found in cells that belong to the lymphocyte lineage. In this study we demonstrated that IV³NeuAc-nLc₄ inhibits the proliferation of Epstein-Barr virus (EBV) genome-positive Burkitt lymphoma cells of the lines Raji and P3HR-1K. IV³NeuAc-nLc₄-induced growth inhibition is associated with an increase in G₀/G₁ phase cells and a reduced expression of CD21 and HLA-DR antigens on Raji cells. These data suggest that IV³NeuAc-nLc₄ may affect differentiation of lymphoma cells. Additionally, the increased expression of viral mRNA species which are characteristic for the lytic viral cycle in the non-producer line Raji and the enhanced release of virions from the producer line P3HR-1K demonstrate that IV³NeuAc-nLc₄ activates the replication of EBV. Growth inhibition and termination of the viral latency suggest that IV³NeuAc-nLc₄ present in monocyte/granulocyte lineage cells may be an effector of the natural defense against EBV persistency and transformation. Received: 20 December 1998     

Detection of the Epstein-Barr virus in primary gastric lymphoma by in situ hybridization

The Epstein-Barr virus (EBV) has been shown to be associated with numerous human malignancies including Burktt's lymphoma and nasopharyngeal lymphoepithelioma. In addition, some typical gastric adenocarcinomas were also recently reported to demonstrate EBV relevance. The present study was designed to detect EBV in primary gastric lymphoma, using the in situ hybridization (ISH) method, in which oligo-nucleotide probes for the EBERl RNA and the EBV DNA W region have been used. Of the 49 cases of primary gastric lymphoma studied, which all showed B cell immunopheno-type, EBER1 sequences could only be found in four cases, including two low-grade cases and two high-grade cases of histological subtypes while the number of positive cells was less than 50% of the tumor cells. In one case of low-grade mucosa associated lymphoid tissue (MALT) lymphoma, the EBER1 -positive neoplastic cells were found in the regional lymph node, but the primary site of the stomach showed no positive signals. The EBV presence was further confirmed by the EBV DNA ISH. Using the ISH method, rare or occasional positive lymphoid cells (probably non-tumorous bystander cells) could be detected in 10 other cases including all histological subtypes. The present study shows that only a small proportion of primary gastric lymphoma is associated with EBV, and such positive cases could be found in both high- and low-grade histological subtypes. It is also suggested that the EBV presence in the neoplastic cells of some cases of primary gastric lymphoma is most likely a secondary phenomenon.     

HLA-G14bp基因多态性与儿童Epstein-Barr病毒感染的相关性分析

目的 通过检测Epstein-Barr病毒(EBV)感染传染性单核细胞增多症(IM)患儿人类白细胞抗原G(HLA-G) 14 bp插入/缺失多态性及血浆可溶性HLA-G(sHLA-G)水平,探讨其与儿童EBV感染IM的相关性.方法 采用PCR结合聚丙烯酰胺凝胶电泳(PCR-PAGE)技术,对102例EBV感染IM患儿及165例正常对照儿童进行了HLA-G 14 bp插入/缺失多态性检测;采用ELISA检测了51例EBV感染IM患儿及146例正常对照儿童血浆sHLA-G水平.结果 EBV感染IM组与正常对照组HLA-G 14 bp插入/缺失基因型多态性分布频率差异有统计学意义(X2=6.742,P=0.034),两组等位基因分布频率差异亦有统计学意义(x2=6.672,P=0.01);EBV感染IM组血浆sHLA-G水平明显高于正常对照组,经检验差异有统计学意义(Z=-9.472,P＜0.01),EBV感染IM组不同基因型间血浆sHLA-G水平差异有统计学意义(H=6.09,P=0.048),14 bp+/+基因型组血浆sHLA-G水平明显低于另两组基因型(Z=-2.376,P=0.018).结论 HLA-G 14 bp插入/缺失基因型多态性与儿童EBV感染IM的发生有关,携带14 bp-/-基因型或缺失14 bp等位基因的儿童可能更易发生EBV感染.血浆sHLA-G水平可作为EBV感染IM的辅助诊断指标之一.     

Epstein-Barr virus latent and replicative gene expression in oral hairy leukoplakia

Oral hairy leukoplakia is an epithelial lesion of the tongue associated with productive infection by Epstein-Barr virus (EBV). However, no data concerning the pattern of EBV latent gene expression have been reported, and it remains unresolved whether true latent infection occurs in basal cell layers of oral hairy leukoplakia. We have studied six cases of oral hairy leukoplakia using monoclonal antibody immunohistology for EBV latent--EB nuclear antigen (EBNA) 1, EBNA 2 and latent membrane protein 1 (LMP 1); immediate-early (BZLF1); and replicative (EA, VCA, MA) proteins, and for the EBV-receptor (CD21 antigen). EBV DNA was demonstrated by nucleic acid in situ hybridization. Mid- to upper-zone keratinocytes contained EBV DNA and co-expressed EBNA 1, EBNA 2 (5 of 6 cases), LMP 1, BZLF1 protein, EA, VCA and MA. No EBV genome or gene expression could be demonstrated in basal or parabasal cells. Spinous keratinocytes were labelled by anti-CD21 antibodies HB5 and B2, but did not express the EBV-receptor as defined by reactivity with OKB7. The co-expression of latent and replicative infection-associated antigens is striking, indicating possible functional roles for latent proteins during the productive cycle. Our results suggest that oral hairy leukoplakia is caused by repeated direct infection of upper epithelial cells with virus from saliva or adjacent replicatively infected cells, rather than by a latent EBV infection of basal epithelial cells with a differentiation-dependent switch to productive infection as previously proposed.     

Chediak-Higashi Syndrome: Immunological responses to Epstein-Barr virus studies in gene heterozygotes

Immunologic studies were performed in five fathers and nine mothers of patients with Chediak-Higashi Syndrome (CHS). Antibody response to Epstein-Barr virus capsid antigen was higher than in normal controls. Antibodies to diffuse component of the early antigen were not detected and serum antibodies to the restricted component of the early antigen were observed in 64% of the subjects studied. Low natural killer activity and increased proportions of OKT8 positive cells were increased. These data indicate that immunologic alterations similar to those seen in CHS patients can be observed in their asymptomatic parents.     

A study of the association of Epstein-Barr virus with Burkitt's lymphoma occurring in a Chinese population

There is a strong association (approximately 95%) of endemic Burkitt's lymphoma with Epstein-Barr virus (EBV), whereas the association is weak for the sporadic form occurring in Western countries (approximately 15%). In the Middle East, North Africa and South America, 60–80% of Burkitt's lymphomas harbour EBV. These epidemiological differences suggest that either the endemicity of EBV or socio-economic conditions, or both, may influence the pathogenetic role of EBV in Burkitt's lymphoma. Since only meagre data are available on Asians, this study was performed to address this issue by studying cases from Hong Kong, where EBV seroconversion occurs in the first few years of life but the socio-economic conditions approach those of Western countries. In situ hybridization for EBV encoded RNAs (EBERs) was performed on paraffin sections of 18 cases of Burkitt's lymphoma. Labelling of the neoplastic cells was detected in five cases (27.7%). In contrast, among 54 cases of B-cell lymphomas of various subtypes studied for comparison, signals for EBER were detected in only one case each of T-cell-rich large B-cell lymphoma, anaplastic large cell lymphoma and Reed-Sternberg-like cells occurring in B-cell chronic lymphocytic leukaemia/small lymphocytic lymphoma. The strong labelling with oligo-dT probe (which hybridized with the polyadenylated ends of mRNA) in all cases suggested that the negative results were genuine and not due to poor preservation of RNA in the tissues. Thus, among B-cell neoplasms occurring in Chinese, Burkitt's lymphoma shows a statistically stronger association ( P < 0.01) with EBV than with other types of B-cell lymphoma. The available data also suggest that the socio-economic status of the country rather than exposure to EBV at an early age is the crucial factor determining the role of EBV in the genesis of Burkitt's lymphoma.     

Functional characterization of partially purified Epstein-Barr virus DNA polymerase expressed in the baculovirus system

The DNA polymerase gene of Epstein-Barr virus (EBV) was cloned into baculovirus transfer vector (pBlueBac). The recombinant baculovirus (AcEBP-15) was obtained by cotransfection ofSpodoptera frugiperda (Sf9) cells with infectious DNA fromAutographa californica multiple nuclear polyhedrin virus (AcMNPV) and pBlueBac plasmid carrying EBV polymerase gene. Infection of Sf9 cells with the recombinant virus produced substantial quantities of the EBV DNA polymerase protein of the expected size (110 kD). The identity of the EBV polymerase 110-kD polypeptide was determined by (a) immunoprecipitation and Western blot analyses with rabbit polyclonal antiserum specific for a synthetic peptide derived from the coding sequence of the polymerase gene; (b) identification of a polypeptide of identical size (110 kD) from EBV-infected cells; (c) measurement of DNA polymerase activity similar to that of the enzyme induced in EBV-infected cells; and (d) neutralization of the enzymatic activity by the rabbit antiserum and inhibition by phosphonoacetic acid. Our results indicate that the baculovirus expression system provides large quantities of functional polymerase suitable for biochemical and structural analyses, thereby furthering our understanding of the mechanism of viral DNA replication and its inhibition by antiviral drugs.     

Absence of Epstein-Barr virus in olfactory neuroblastoma

AIMS: The sinonasal region is a frequent site for Epstein-Barr virus (EBV) related tumours, including nasopharyngeal carcinoma, sinonasal undifferentiated carcinoma and malignant lymphoma. Olfactory neuroblastoma is a rare neoplasm, arises from olfactory epithelium, is found in the upper nasal cavity, and may be confused morphologically with the above tumours. Our aim was to determine whether EBV is associated with olfactory neuroblastoma. METHODS: We collected tissue samples for 16 olfactory neuroblastomas over an 11-year period at Kaohsiung Medical University Hospital. Diagnoses were confirmed from pathological review and immunohistochemistry. We used in situ hybridisation for EBV encoded small RNAs in those tumours. RESULTS: None of the epithelial cells in the 16 cases of olfactory neuroblastoma was positive for EBV. CONCLUSIONS: EBV does not play a major role in the aetiology of olfactory neuroblastoma.     

Regulation of the expression of the Epstein-Barr virus early gene BFRF1

The switch from latency to lytic phase of Epstein-Barr virus (EBV) is coordinated by the expression of two viral transactivators known as ZEBRA and RTA. The BFRF1 gene has been shown to be transcribed during the early phases of EBV lytic cycle. Here, we characterized the BFRF1 promoter showing that ZEBRA transfection stimulated BFRF1 expression, whereas RTA induced BFRF1 only after the transfection of an amount of plasmid largely in excess than that sufficient to stimulate the expression of other RTA-responsive genes. However, a co-operative effect between ZEBRA and RTA in the expression of BFRF1 is evident since the transfection of RTA can rescue the transactivating capacity of a mutant of the ZEBRA protein, known as Z(S186A), that has a substitution affecting the DNA binding region. Moreover, we identified one ZEBRA-responsive element (ZRE) and one RTA-responsive element (RRE) within the BFRF1 promoter region.     

腮腺淋巴上皮瘤样癌与EB病毒感染的关系

目的：研究ＥｐｓｔｅｉｎＢａｒｒ 病毒（ＥＢＶ）与腮腺淋巴上皮瘤样癌（ｌｙｍｐｈｏｅｐｉｔｈｅｌｉｏｍａｌｉｋｅｃａｒｃｉｎｏｍａ,ＬＥＬＣ）的关系,并检测瘤细胞内ＥＢＶ 基因编码产物。方法：作者收集了中山医科大学所属病理科１９８６ 年１ 月至１９９５ 年１２ 月间３２ 例腮腺ＬＥＬＣｓ．。３２ 例ＬＥＬＣ石蜡包埋标本再次切片。采用免疫组化和原位核酸杂交法检测瘤细胞内ＥＢＶ 基因表达产物。结果：（１） 在１２５例腮腺癌中有３２ 例淋巴上皮瘤样癌,占总病例的２５－６％ （３２／１２５） 。（２）所有３２ 例腮腺ＬＥＬＣ组织中均有数量不等的ＥＢＮＡ１ 和ＥＢＥＲｓ 阳性瘤细胞。（３）２７ 例ＬＥＬＣ 组织中部分瘤细胞表达ＬＭＰ１ 。（４） 所有标本中均未见ＺＥＢＲＡ 阳性细胞。（５）３２例腮腺ＬＥＬＣ组织中ＥＡＤ、ＶＣＡ和ＭＡ的阳性表达率分别为７１－９ ％（２３／３２） 、６８－８ ％（２２／３２） 和１２－５％ （４／３２） 。结论：（１） 在鼻咽癌高发的广州地区,腮腺ＬＥＬＣ的发病率也较高。（２）腮腺ＬＥＬＣ 组织中均有ＥＢ病毒感染。（３）ＥＢ病毒在腮腺ＬＥＬＣ的感染主要为潜伏Ⅱ型,即表达ＥＢＮＡ１ 、ＥＢＥＲｓ 和ＬＭＰ１     

鼻咽癌组织中EB病毒潜伏相关基因的表达

目的： 通过检测鼻咽癌组织中EB病毒的潜伏膜蛋白LMP1的序列以及LMP1、EBNA1、EBNA2的mRNA表达来探讨EB病毒的感染状态及其表达产物与鼻咽癌的关系。方法: 应用PCR法检测鼻咽癌组织中LMP1 DNA的存在，并对鼻咽癌来源的LMP1和EB病毒永生化狨猴B淋巴细胞系B95-8来源的LMP1进行测序，比较序列的差异。利用巢式RT-PCR检测鼻咽癌组织中LMP1、EBNA1、EBNA2的mRNA表达。结果: 47例鼻咽癌组织均含有LMP1 DNA，所有鼻咽癌来源的LMP1 DNA与B95-8来源的LMP1 DNA序列比较均存在着多个单核苷酸变异，最明显的是XhoⅠ酶切位点的丢失。测序后显示鼻咽癌来源的LMP1 DNA有30个核苷酸的丢失。巢式RT-PCR显示LMP1、EBNA1、EBNA2在鼻咽癌中的mRNA表达率分别为76.6％、80.0％和74.5％。其中EBNA1的表达是由Qp启动的，而B95-8细胞中EBNA1的表达是由Cp启动的。结论: 鼻咽癌中EB病毒的作用途径比较复杂，LMP1、EBNA1、EBNA2等潜伏期基因还有早期裂解基因BARF1均可能参与鼻咽癌的发生发展过程。     

Pyothorax-associated lymphoma: Development of Epstein-Barr virus-associated lymphoma within the inflammatory cavity

Pyothorax-associated lymphoma (PAL) is a B cell lymphoma that develops in Japanese patients with tuberculosis-associated chronic pyothorax (TaCP). Epstein-Barr virus (EBV) has been shown to be causally related to PAL. To clarify the developmental process of PAL, the systemic and local presence of EBV, and serum profile of anti-EBV antibodies was investigated in TaCP. EBV genome was found in peripheral blood mononuclear cells by PCR in a 10–⁴-^-10–⁵ amount of Raji cell-DNA in three of four patients with TaCP, but was also identified in patients with pyothorax caused by other diseases (2/2) or without pulmonary diseases (2/6). EBERl in situ hybridization and EBNAS immunocytochemistry revealed clusters of EBV-carrying cells in the cavity content (3/18) but not at the pyothorax wall; EBV(+) histological lymphoma cells were found in two cases and EBV(+) mononuclear cells were found in one case. A simultaneous increase in serum titers of anti-EBV viral capsid antigen IgG and IgA antibodies was observed in TaCP (4/16). These results suggest that a local factor, an inflammatory cavity, has a pivotal role in the development of PAL, which might be reflected in the Serum titers of anti-EBV antibodies in patients with TaCP.