RESUMO
Epstein-Barr virus (EBV) is a potent inducer of polyclonal B lymphocyte proliferation and a tool for the establishment of human B lymphoblastoid cell lines (B-LCLs), which have proven useful for several human immunologic applications. B-LCLs serve as efficient antibody-producing cells and antigen-presenting cells. In spite of these advantages, the cloning efficiency of B-LCLs is less than 1%. In order to generate clones of B-LCLs, we cultured B-LCLs with and without canine stromal cell line, DO64, as feeder cell which was immortalized by transduction of retrovirus encoding E6 and E7 of the human papilloma virus type 16 (HPV-16), which was defined to produce various cytokines including stem cell factor (SCF) and interleukin- 6 (IL-6). After 3 weeks of B-LCLs cultured with DO64, 8.3% and 37.5% in 1 cell and 3 cells per well were efficiently cloned, respectively. There was no significant effect on growing of 8-LCLs without DO64 cells and on high concentration of FBS. The cloning efficiency of B-LCLs transduced by retrovirus cultured with and without DO64 cells was 4.2% and 0% in 3 cells per well, respectively, while that of stable transfectant 33.3% and 8.3% in 1 cell per well, respectively. Our results suggest that the use of DO64 cells as feeder cells might permit the cloning of B-LCLs. This efficient cloning of B-LCLs could be used for the convenient source of autologous antigen-presenting cells expressing foreign antigen for the study of human immune responses in vitro, and for a variety of additional purposes, such as the production of human monoclonal antibodies.