Takao Aya

An Epstein-Barr virus-producer line Akata: establishment of the cell line and analysis of viral DNA.

An Epstein-Barr virus (EBV)-producer line, designated Akata, was established from a Japanese patient with Burkitts lymphoma. The Akata line possessed the Burkitts-type chromosome translocation, t(8q-; 14q+), and was derived from the tumor cell. Akata cells produced a large quantity of transforming virus upon treatment of cells with anti-immunoglobulin antibodies (Takada, 1984). Southern blot analysis of viral DNA indicated that the Akata EBV is nondefective and more representative of wild-type viruses. Akata cells should be useful as a source of EBV.

Chromosome translocation and c-MY Cactivation by Epstein-Barr virus and Euphorbia tirucalli in B lymphocytes

Dual exposure to Epstein-Barr virus and purified 4-deoxyphorbol ester derived from the plant Euphorbia tirucalli induced a high frequency of chromosomal rearrangements in human B lymphocytes in vitro. Rearrangements most commonly affected chromosome 8, the chromosome most often showing structural changes in Burkitts lymphoma (BL) cells. E tirucalli is indigenous in parts of Africa where BL is endemic and may be an important risk factor for the disease.

Epstein-Barr Virus, Burkitt’s Lymphoma, and an African Tumor Promoter

The Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that immortalizes in vitro primary human B lymphocytes. EBV is clinically associated with certain B-cell malignancies in man, such as Burkitt’s lymphoma (BL) in tropical Africa and opportunistic lymphomas in immunodeficiency (1–3). The vast majority of the African BL cases are positive for EBV genomic DNA and also for specific reciprocal chromosome translocations mostly between chromosomes 8 and 14. EBV exists worldwide, but Burkitt’s lymphoma is endemic in tropical Africa (4). In contrast to BL cells, with their specific chromosome changes, EBV-immortalized B cells have a normal karyotype (5). A cofactor(s) or risk factor(s) may therefore have to be taken into account, in addition to EBV, in the determination of the genesis of African BL. Holoendemic malaria may play a role in lowering EBV-specific cellular immunity and stimulating EBV infection (6, 7). We tried a different approach to the study of the genesis of Burkitt’s lymphoma (8).

The simultaneous observations of immunofluorescence and cellular morphology in viral infections: a new procedure.

A simple method for comparative observations of immunofluorescence and cellular morphology has been developed in the investigation of Epstein-Barr virus (EBV) infection and oncogenesis. When cells were stained for immunofluorescence of EBV-determined nuclear antigen, early antigens, or the viral capsid antigen, followed by treatment with hematoxylin, viral marker expression and cellular morphology could be simultaneously observed in individual cells by simply changing ultraviolet illumination to visible light. In our double-staining method, hematoxylin was not counteractive to specific immunofluorescence, and pretreatment of cells with antibodies did not affect hematoxylin staining. This method may possibly be more widely applied in virology and other fields.

An Environmental Plant Factor Enhancing Epstein-Barr Virus-Induced Events in East Africa

Our 3-year-survey in Kenya and Tanzania has shown a geographical coincidence of African Burkitt’s lymphoma (BL) and a particular plant species, Euphorbia tirucalli. The Euphorbia tirucalli had a potent promoter substance, mainly 4-deoxyphorbol ester, of Epstein-Barr (EBV)-induced events, induction of the latent viral genome and enhancement of the lymphocyte transformation, to grow closely associated with daily life of the local people in highly BL-endemic villages.