In Vitro Transformation of Human B-Cell Follicular Lymphoma Cells by Epstein-Barr Virus1

Human low-grade B-cell lymphoma cells cannot be readily maintained in long-term tissue culture. In an effort to obtain low-grade B-cell lymphoma cell lines for in vitro study, we used Epstein-Barr virus (EBV) as a transforming agent. T-cells were removed prior to EBV transfor mation by rosetting with sheep erythrocytes, followed by treatment with anti-Tl 1 monoclonal antibody plus complement. The resulting cell pop ulation was cocultured with EBV prepared from tissue culture supernatants of marmoset cell line B9S-8. Identical immunoglobulin gene rear rangements of tumor cells and EBV-transformed cells were the criteria used to determine that the transformed cells were of tumor origin. DNA was prepared from both biopsy tissue and EBV cell lines and digested with restriction endonucleases, and Southern blots were prepared by standard methods. B-cells isolated from biopsies of four low-grade B-cell lymphomas of follicular, small cleaved cell type and one of follicular, mixed cell type were transformed by EBV into rapidly growing in vitro tissue culture lines. Two of the five transformed cell lines had immuno globulin heavy chain and light chain gene rearrangements which were present in cells from the original tumor biopsy, indicating that these EBV-transformed cell lines are of tumor origin.