Saichiroh Tanaka

Differences in the ability of cells to fuse are mediated by strains of epstein-barr virus

Epstein‐Barr virus (EBV) preparations from both NPC‐KT cells (NPC‐EBV) and P3HR‐1 cells (HR‐l‐EBV) can induce cell fusion between EBV receptor (EBVR)‐positive Raji cells and EBVR‐negative cells, but other strains of EBV cannot induce cell fusion. The effect of these two EBV isolates on ability of cells to fuse has been studied to determine if there are differences in the biological properties of the different EBV isolates, particularly the isolates obtained from nasopharyngeal carcinoma such as NPC‐EBV. The frequency of cell fusion between NPC‐EBV‐superinfected Raji cells and EBVR‐negative epithelial cells (Ad‐AH) was increased more than 30‐fold in the presence of medium containing 1% dimethylsulfoxide (DMSO). However, the frequency of cell fusion between HR‐1‐EBV‐superin‐fected Raji cells and Ad‐AH cells was unaffected under the same conditions. The data show that differences in the ability of cells to fuse ore induced by variants of EBV in response to DMSO. These differences may be important in elucidating the different biological properties of EBV isolates and might have implications for the pathophysiology of EBV‐associated illness.

The human nasopharynx as a reservoir for Epstein-Barr virus.

Nineteen human nasopharyngeal tissue specimens biopsied from patients with suspected nasopharyngeal carcinoma (NPC) and 15 adenoid tissue specimens obtained by surgery were successfully grown in culture without bacterial and fungal contamination. Fibroblastic growth developed in all of the cultures. In some cases, epithelial growth was also seen among the fibroblastic growth. The cells became round and floated in the culture fluid between 19th and 57th day of culture in 6 out of 10 NPC tissue cultures, 3 out of 9 tissue cultures of apparently normal nasopharyngeal mucosa of patients referred for exclusion of NPC, and 4 out of 15 adenoid tissue cultures. The floating cells consisted of B-lymphoblastoid cells and were positive Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA). The data suggest that a small number of B-lymphocytes in the human nasopharynx serve as a reservoir for EBV.

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.

Infectious mononucleosis in the nasopharynx with a histological picture of malignant lymphoma

SummaryThe present report describes the case history of an 8-year-old girl with a suspected malignant lymphoma of the nasopharynx that was subsequently proven to be due to infectious mononucleosis. The literature is reviewed.

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 Burkitts 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.

Interactions between Epstein-Barr Virus (EBV) and Human Cell Lines: Growth and EBV Induction

Differences in in vitro growth characteristics between Epstein-Barr virus (EBV) genome-negative and genome-positive lymphoblastoid cell lines and between EBV genome-negative and genome-positive epithelial cell lines were investigated. All EBV genome-positive cells were able to grow in medium containing only 0.75% fetal calf serum (FCS), whereas no EBV genome-negative cells were able to grow at this low concentration. However, there was no clear difference between the growth of the two EBV genome-negative lymphoblastoid cell lines (BJAB and Ramos) and two EBV genome-positive BJAB and Ramos sublines (BJAB/B95-8 and Ramos/B95-8) in medium containing more than 2.5% FCS. On the other hand, an EBV genome-positive clone of A2L/AH epithelial hybrid cells (cl-1) grew in both concentrations of FCS better than an EBV genome-negative clone of A2L/AH cells (cl-654). In addition, there was a difference in EBV induction between EBV genome-positive lymphoblastoid (BJAB/B95-8 and Ramos/B95-8) and epithelial (cl-1) cells after treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). Treatment of BJAB/B95-8 and Ramos/B95-8 cells with TPA induced a low percentage of EBV-induced early antigen but not viral capsid antigen, whereas treatment of cl-1 cells with TPA induced both early antigen and viral capsid antigen.

Case Report: Congenital Dermoid Cyst at the Base of the Tongue

A rare case of congenital dermoid cyst at the base of the tongue in a 6-year-old child is presented. The lingual lesion was surgically excised. The literature is reviewed and discussed.

Spontaneous Lymphoblastoid Transformation of Cells Obtained from Human Tonsils

Spontaneous lymphoblastoid transformation of cells obtained from 25 human tonsils were investigated. Three Epstein-Barr virus (EBV) genome-positive lymphoblastoid cell lines were spontaneously established in tissue cultures in vitro from human tonsils. In addition, the frequency of spontaneous lymphoblastoid transformation was increased by the treatment of tumor promoter, 12-0-tetradecanoylphorbol-13-acetate and 18 lymphoblastoid cell lines were established. The data suggest that the human tonsil is a reservoir for EBV.

Development of Significant Sternoclavicular Joint Hypertrophy following Radical Neck Dissection

Radical neck dissection (RND) has proved to be effective in the en bloc removal of metastatic lymph nodes in the neck. This paper describes a case with severe sternoclavicular joint hypertrophy following RND. This condition should be differentiated both clinically and radiologically from metastases of the head of the clavicle. Computed tomography was found to be of value in the diagnosis of the condition.

Further studies on growth characteristics of epstein-barr virus (EBV) genome-positive and -negative epithelial hybrid cell lines

Differences in tumorigenicity between the Epstein‐Barr virus (EBV) genome‐negative and ‐positive epithelial A2L/AH hybrid cell lines have been described recently. Further differences in growth characteristics of the two epithelial hybrid cells have since been examined. Differences were found in doubling time and cloning efficiency in agarose of the two cell lines. In addition, the EBV genome‐negative epithelial hybrid cell line (cl‐654), unlike the EBV genome‐positive epithelial hybrid cell line (cl‐1), failed to grow in the unmanipulated nude mice, but was successfully transplanted in 60Co‐irradiated nude mice. The histopathologic findings of tumors induced by the inoculation of cl‐654 cells in nude mice showed more differentiated carcinoma than the findings of tumors induced by cl‐1 cells.