Epstein–Barr virus (EBV)‐positive pyothorax‐associated lymphoma (PAL): chromosomal integration of EBV in a novel CD2‐positive PAL B‐cell line

Abstract

Summary. Pyothorax-associated lymphoma (PAL) is a clinico-pathological entity arising in the pleural cavity of patients with long-standing inflammatory pyothorax. PAL is closely associated with Epstein-Barr virus (EBV), but how this virus contributes to the development of the lymphoma is unknown. We have successfully obtained a novel EBV-infected PAL cell line, designated Pal-1. The cell line and its source coexpressed CD2 and CD20 molecules, but other representative B-and T-cell markers such as CD1, CD3, CD5, CD7, CD10 and CD19 were not found. The B-cell origin of Pal-1 cells was proven by rearrangement of the immunoglobulin heavy-and light-chain genes without rearranged T-cell receptor genes. Both the cell line and primary tumour cells carried monoclonal EBV genome. Although EBV genome is known to be maintained as circular extrachromosomal DNA, neither circular nor linear extrachromosomal EBV DNA was detectable in Pal-1 cells by in situ lysis gel analysis. Fluorescence in situ hybridization demonstrated viral integration at a marker chromosome mostly consisting of the centromere region of chromosome 1. The viral integration event may enhance a chromosomal instability at the insertion site. This cell line represents the first example of EBV integration in PAL and could enable the study of the potential role of integrated viral infection in the development of PAL as well as mechanism of the aberrant phenotype expression.

Epstein–Barr virus is integrated between REL and BCL-11A in American Burkitt lymphoma cell line (NAB-2)

“…Previous studies demonstrated the integration of EBV in the chromosomes of tumor cells in biopsy specimens or cell lines of BL, 7,10,11 other kinds of B-cell lymphomas, 8,20 and NPC. 9,21 In these studies, integration sites of EBV were indirectly identified by Gardella gels 22 and/or by Southern blot analysis.…”

Visualization of episomal and integrated Epstein‐Barr virus DNA by fiber fluorescence in situ hybridization

“…2 During latency, EBV DNA persists as an episome in the nuclei of host cells, or can be integrated into the cellular genome via the TR sequences. [3][4][5][6][7] Integration may initiate transformation events by causing chromosomal instability, [8][9][10] or may provide a cis-acting mechanism for altering gene regulation or structure. 11,12 Hence, if integration has an effect on viral or cellular gene expression, 5,13 it could be directly linked to the oncogenic properties of EBV, 14 mediating continuous cell proliferation.…”

Diversity of Epstein–Barr virus BamHI-A rightward transcripts and their expression patterns in lytic and latent infections

“…4). Cell line cells harbouring an integrated BARTs expression in EBV-infected cells EBV genome cannot readily be led to the lytic cycle, because lytic replication requires episomal viral DNA (Rickinson & Kieff, 2001;Lawrence et al, 1988;Chevallier-Greco et al, 1986;Daibata et al, 2002;Ooka et al, 1984). On the other hand, all four major transcripts were detected at much higher levels in LCLs.…”