January 2001, Volume 15, Issue 1, Pages 148 - 156

Original Manuscript

Establishment of a follicular lymphoma cell line (FLK-1) dependent on follicular dendritic cell-like cell line HK Y Kagami1, J Jung2, YS Choi2, K Osumi3, S Nakamura4, Y Morishima1 & M Seto5 1Department of Hematology and Chemotherapy, Aichi Cancer Center Hospital, Nagoya, Japan     2Laboratory of Cellular Immunology, Alton Ochsner Medical Foundation, New Orleans, LA, USA     3Otsuka Assay Laboratory, Tokushima, Japan     4Department of Pathology, Aichi Cancer Center Hospital, Nagoya, Japan     5Department of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya, Japan     Correspondence to: Y Kagami, Department of Hematology and Chemotherapy, Aichi Cancer Center, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan; Fax: 81 52 763 5233

Keywords

follicular lymphoma;   follicular dendritic cell;   cell line;   growth factor;   apoptosis

Abstract

A novel cell line, FLK-1, was established from bone marrow cells of a patient with follicular lymphoma by means of co-culture with follicular dendritic cell (FDC)-like cell line HK. Immunophenotypic analysis showed that FLK-1 expressed CD10, CD19, CD20, CD38, IgG and HLA-DR, which is a typical feature of germinal center B cells. Cytogenetic analysis of FLK-1 demonstrated t(14;18)(q32;q21) translocation involving BCL2 and immunoglobulin heavy chain genes. Especially noteworthy is that the growth of FLK-1 was found to be dependent on a FDC line, HK. When HK cells were removed from the culture, FLK-1 cells stopped growing and eventually died. An apoptotic mechanism appeared to be involved as indicated by the presence of chromosome condensation and DNA ladder formation. The culture experiment using micropore membranes showed that soluble factor(s) of HK cells supported the growth, while direct cell-to-cell contact appeared to be necessary for long-term cell proliferation. These findings suggest the importance of the micro-environment for follicular lymphoma cells to grow. The FLK-1 cell line may thus prove to be useful for studying the growth mechanism of follicular lymphoma and provide new insights into the pathogenesis of follicular lymphoma. Leukemia (2001) 15, 148-156.

Received 2 February 2000; Accepted 14 September 2000

^© Macmillan Publishers Ltd 2001