GENE ENGINEERING EB VIRUS MEMBRANE ANTIGEN IN DETECTION OF MA-IgA ANTIBODY(COMPARISON WITH VCA-IgA AND EA-IgA ANTIBODIES)

With gene engineering EB virus membrane antigen as the diagnostic antigen, indirect immunofluo-rescence (IF) assay was used to detect IgA antibody against EB virus membrane antigen (MA-IgA) in sera from 202 nasopharyngeal carcinoma (NPC) patients and 315 controls (normal and patients with other tumors). MA-IgA antibody was positive in 96.8% of the pretreatment NPC patients with a GMT of 1:36.3. MA-IgA detection by this method was more sensitive than EA-IgA detection by IE. In contrast, patients with tumors other than NPC were negative for MA-IgA antibody. 9.1% of VCA-IgA positive persons were MA-IgA positive with a GMT of less than 1:5. No MA-IgA positive was found in VCA-IgA negatives. The results indicated that this method was relatively specific. In the treatment group, the positive rate and GMT of MA-IgA antibody declined with increase in survival time and the decline was faster than VCA-IgA. When recurrence or distant metastasis developed, similar to VCA-IgA and EA-IgA antibodies, the positive rate and GMT of MA-IgA antibody increased to its pretreatment level. Therefore, MA-IgA detection might be valuable in the early diagnosis and monitor of NPC.

DETECTION OF EB VIRUS EARLY ANTIGEN IN NASOPHARYNGEAL CARCINOMA (NPC) USING A NEW MONOCLONAL ANTIBODY--BAE-5

A mouse monoclonal antibody against EB virus EA-R named BAE- 5 was prepared applying hybridoma technique by use of n-butyric add and croton oil induced Raji cells as immunogen.And then, 34 NPCs and 29 mm-NPC neoplasms were detected by the BAE-5 using APAAP immunohistochemical staining method.The results Indicated that all of the 34 NPCs and 9 of the 29 non-NPC neoplasms could reacted with the BAE-5 in spite of the columnar epithelium reserve cells showing positivity also. It is reasonable to come to the conclusion that most of the NPC cells can not only harbour EBV DNA but some of them be able to express EA-R. Some non-NPC neoplasms being demonstrated BAE-5 posttlvlty may be due to the presence of EBV EA- R antigenic epitope or polypeptides simulating the structure of EA-R. The authors think that these findings have theoretical significance for understanding the role of EBV- encoded poiypeptides, especially EA complex, In the development and progression of NPC as well as some non- NPC neoplasms harbouring EBV-DNA.

Interrelationship between EB Virus and Sjogren's Syndrome

The authors designed a specific primer of EB virus Bam W fragment and EBV DNA sequence by using the polymerase chain reaction（PCR） to amplify the EBV DNA sequences and the performing the hybridization analysis（dolblot and Southern transfer） with a γP labelled internal olignoucleotide probe.

Expression of matrix metalIoproteinase-9 in nasopharyngeal carcinoma and association with Epstein-Barr virus infection

Objective: To evaluate the expression of matrix metalloproteinase-9 (MMP9) in nasopharyngeal carcinoma and the association between MMP9 and Epstein-Barr virus infection. Methods: The MMP9 expression was studied by immunohistochemical analysis; and Epstein-Barr virus encoded small nuclear mRNA-1 (EBER-1) produced by in situ hybridization were examined in 41 nasopharyngeal carcinoma sections, and the relation between them, and the associations of MMP9 with clinical features were statistically analyzed. Results: Positive expression rate of MMP9 was 73.17%. The expression of MMP9 showed significant positive correlation with the expression of EBER-1(γ=0.483, P=0.001 ). There was significant association of MMP9 expression with lymph nodes metastasis and clinical stage (P<0.001), non-significant association with age, gender, pathological classification and T classification. Conclusions: The highly pronounced expression of MMP9 is associated with cervical lymph nodes metastasis. Epstein-Barr virus can enhance NPC metastasis by up-regulating the expression of MMP9.

Gene Therapy of HSV-TK Transferred by the EBV based Expression Vector on Experimental Hepatocellular Carcinoma

To study the therapeutic effects of herpes simplex virus thymidine kinase gene transferred by the EBV based expression vector on experimental hepatocellular carcinoma, pDR2 TK gene was delivered into human hepatocellular carcinoma cell line SMMC 7721 by using liposome mediated transfection technique,and then gene expression was detected by RT PCR, and the killing effects were examined through MTT method. In the nude mice hepatoma model,the antitumor effects of pDR2 TK /GCV system was evaluated in terms of tumor growth. MTT results showed that the pDR2 TK /GCV had cytotoxic effect and about 70 % SMMC 7721 cells were killed when GCV was at 1000 μmol/L. In vivo experiment showed that the tumor size in nude mice with transferred pDR2 TK gene was significantly smaller than that in control group . On the 10th day the tumor in 3 mice (60 %) disappeared completely after GCV treatment. It is concluded that the pDR2 TK/GCV system has marked killing effects on the experimental hepatocellular carcinoma.

ESTABLISHMENT OF HIGH RISK POPULATION AND PRECANCEROUS LESION OF NASOPHARYNGEAL CARCINOMA(NPC)

A prospective study was done by the examination of nasopharyngoscope, reaction of EB virus's antigens and antibodies, nasopharyngofibroscope, pathological and EB virus's DNA, EBERs, etc. of about 100000 persons in high risk area of NPC in Guangdong Province, China from 1986 to 1995. If any one of the following four conditions is present in some persons, i.e., (1) EBV VCA/IgA titer>1:80, (2) EBV EDAb>60%, (3) Dual or triple positiveness in VCA/IgA, EA/IgA and EDAb, (4) Any one of VCA/IgA, EA/IgA and EDAb keeps high titer or going up, they should be regarded as in precancerosis of NPC. The moderate or severe heteroplasia and heterometaplasia of nasopharyngeal mucosa are the precancerous lesions of NPC. Some individual who is in precancerosis or with precancerous lesion should be regarded as the high risk population of NPC. The results are of important scientific basis for screening and second degree prevention of NPC.

POPULATION CHARACTERS IN HIGH RISK PEDIGREES OFNASOPHARYNGEAL CARCINOMA (NPC)

Objective: To investigate population characters in high risk pedigrees of NPC in Guangdong area and to explore the effect each other between tumor genetic susceptibility and infection of EB virus on pathogenic mechanism. Methods: Pedigree investigation, examination of DNA fingerprint, multi-antibodies of EB virus and nasopharyngeal cavity were done for all of the members in each high risk pedigree. Results: High positive rate of EBV VCA/IgA (23.22%), high percentage of high risk population of NPC (6.53–10.40%), high detected rate of malignant tumor (9552.59/105), and high detected rate of NPC (8464.32/105) were discovered and NPC was most common in first degree relative of a pedigree. Conclusion: Tumor genetic susceptibility, infection of EB virus might play a role in coordination of reinforced effect on occurrence of NPC.

Fas/FasL and Complement Activation are Associated with Chronic Active Epstein-Barr Virus Hepatitis

Background and Aims:Chronic active Epstein-Barr virus hepatitis(CAEBVH)is a rare and highly lethal disease char-acterized by hepatitis and hepatomegaly.This study aimed to investigate the clinicopathological features and pathogenic mechanisms of CAEBVH.Methods:Ten patients with con-firmed Epstein-Barr virus hepatitis infection were enrolled.The clinicopathological characteristics of these patients were summarized and analyzed.Flow cytometry was utilized to detect peripheral blood immune cell phenotypes and whole exome sequencing was used to explore pathogenic genetic mechanisms.Lastly,immunohistochemical staining was em-ployed to verify pathogenic mechanisms.Results:Clinical features observed in all Epstein-Barr virus hepatitis patients included fever(7/10),splenomegaly(10/10),hepatomeg-aly(9/10),abnormal liver function(8/10),and CD8+T cell lymphopenia(6/7).Hematoxylin and eosin staining revealed lymphocytic infiltration in the liver.Positive Epstein-Barr vi-rus-encoded small RNA in-situ hybridization(EBER-ISH)of lymphocytes of liver tissues was noted.Whole exome se-quencing indicated that cytotoxic T lymphocytes and the complement system were involved.The expression of CD8,Fas,FasL,and Caspase-8 expression as well as apoptotic markers was enhanced in the Epstein-Barr virus hepatitis group relative to the controls(p<0.05).Lastly,Complement 1q and complement 3d expression,were higher in CAEBVH patients relative to controls(p<0.05).Conclusions:CAE-BVH patients developed fever,hepatosplenomegaly,and lymphadenopathy.Histopathological changes were a diffuse lymphocytic sinusoidal infiltrate with EBER-ISH positivity.Fas/FasL and complement activation were involved in CAE-BVH patients.

Induction of T-cell immunity against Epstein-Barr virus-associated tumors by means of adenovirally transduced dendritic cells

Background Dendritic cells (DCs) are the most powerful antigen-presenting cells to induce specific T-cell immunity, which plays an important role in the body’s anti-tumor responses. In this study, we assessed the feasibility and efficacy of inducing T-cell immunity against Epstein-Barr virus (EBV)-associated tumors in vivo using dendritic cells transfected with EBV latent membrane 2A (LMP2A) recombinant adenovirus.Methods Cytokine-activated bone marrow-derived DCs transfected with EBV LMP2A recombinant adenovirus were infused into BALB/c mice. Splenic cytotoxic T-cell responses were evaluated by cytotoxicity and interferon-γ production assays. in vivo immune protection was then assessed in the mice tumor models implanted with tumor cells expressing EBV LMP2A.Results DCs transfected with EBV LMP2A recombinant adenovirus could strongly induce EBV LMP2A-specific cytotoxic T-cell responses and upregulate interferon-γ production in vivo. Vaccination using these DCs led to prolongation of overall survival rates in the mice tumor models and retarded tumor growth. Conclusions The results suggest that DCs transfected with EBV LMP2A recombinant adenovirus can serve as a feasible and effective tool for eliciting LMP2A-specific cytotoxic T-cell responses against EBV LMP2A in vivo in the treatment of EBV-associated tumors.