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

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 transformation by rosetting with sheep erythrocytes, followed by treatment with anti-Tl1 monoclonal antibody plus complement. The resulting cell population was cocultured with EBV prepared from tissue culture supernatants of marmoset cell line B95-8. Identical immunoglobulin gene rearrangements 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 immunoglobulin 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.