Search PubMed⌕ Search

Biomedical subjects

K Kvarnung

Publications and source records attributed to K Kvarnung.

3 recordsLinked to original sources
PubMed1993

Integration of a short Epstein-Barr virus DNA fragment in a B95-8 virus converted Burkitt lymphoma line expressing Epstein-Barr nuclear antigens EBNA2 and EBNA5.

We have analysed the expression of transformation-associated viral antigens, the Epstein-Barr virus (EBV) DNA content and the phenotypic characteristics of two B95-8 virus-converted sublines of the EBV-negative Burkitt's lymphoma (BL) line BL28. The converted lines called E95A-BL28 and E95B-BL28, respectively, differed in their EBV gene expression. The E95B convertant expressed virus-encoded nuclear antigens EBNA1 to -6 and the membrane protein LMP1, but only EBNA2 and EBNA5 were detected by immunofluorescence and immunoblotting in the E95A convertant. Only the entire BamHI W, Y and H regions could be detected in the E95A convertant by hybridization of Southern blots with probes covering the BamHI C, W, Y, H, F, E, K and Nhet regions of the EBV genome. EBV episomes were found to be absent in the E95A convertant as seen by Gardella gels. The E95A convertant retained the phenotypic characteristics of the EBV-negative parental line, and remained highly clonable in agarose. In contrast, expression of EBNA1 to -6 and LMP1 was accompanied by a shift towards a more lymphoblastoid cell line-like phenotype and by loss of agarose clonability in the E95B convertant.

Antigens, Differentiation, B-Lymphocyte↗
PubMedDate not supplied

Epstein-Barr virus-infected B-chronic lymphocyte leukemia cells express the virally encoded nuclear proteins but they do not enter the cell cycle.

OBJECTIVES: To understand the mechanism for the refractoriness of B-chronic lymphocyte leukemia (B-CLL) cells for EBV-induced immortalization. STUDY DESIGN/METHODS: Cells from four B-CLL patients were infected with Epstein-Barr virus (EBV). Noninfected and infected aliquots were exposed to CD40L. Five days later, the cultures were analyzed for cell survival, activation, DNA synthesis, and expression of EBV-encoded and of cellular regulatory proteins retinoblastoma (Rb), p53, recombinant sequence binding protein (RBP)Jk, and PU.1. The proteins were detected by immunoblotting and by immunofluorescence. RESULTS: A proportion of the cells were activated and expressed Epstein-Barr nuclear antigens (EBNAs) and elevated Rb level but not latent membrane protein (LMP)-1 and p53. They did not enter the cell cycle. Exposure to CD40L induced DNA synthesis but it did not modify the expression of the EBNAs. CONCLUSIONS: The virus could activate CLL cells, but the full course of the early events that leads to immortalization--as seen in normal B cells--did not proceed beyond a certain point. Compared to B lymphocytes, the critical point is between activation and initiation of the cell cycle.

B-Lymphocytes↗