Proliferative response of highly purified B chronic lymphocytic leukemia cells in serum free culture to interleukin-2 and tumor necrosis factors alpha and beta.
Recent studies have suggested that interleukin-2 (IL-2), tumor necrosis factor (TNF) and a crude preparation of B-cell growth factors (BCGF) have a regulatory role in the proliferation of B-CLL cells. However, interpretation of the experimental data has been complicated by potential methodological pitfalls. To establish the role of these factors in B-CLL growth, we investigated their stimulatory effects under accurately defined in vitro conditions. Purified B-CLL cells were obtained by fluorescence activated cell sorting on the basis of coexpression of CD5 and CD19/CD20/CD24 surface antigens in order to avoid interference of normal cell contamination. Subsequently, the cells were cultured free of serum. TNFs alpha and beta and BCGF induced DNA synthesis in the purified B-CLL cells in five out of six cases, as assessed by 3H-thymidine (TdR) uptake on days 3 and 6 of culture. The stimulating activity of BCGF could be suppressed by the addition of specific anti-TNF monoclonal antibodies, indicating that the BCGF activity had been, to a major extent, due to the presence of TNFs in this impure preparation. IL-2, when added as a single stimulus, induced DNA synthesis in the B-CLL cells in three out of six cases on day 3, but not on day 6 of culture. In some patients, cooperative effects of IL-2 and TNF were observed. Cytogenetic analysis was applied to confirm the CLL origin of the proliferating cells. The phorbol ester TPA or anti-IgM were not required for induction of DNA synthesis in the CLL cells, although TPA potentiated 3H-TdR uptake in three out of six cases, and anti-IgM in one case. Our data demonstrate that IL-2 and TNFs alpha and beta can act as growth factors for B-CLL cells under fully defined in vitro conditions, essentially without the need of TPA or anti-IgM as primary activation signals.
Moberts
R
R
Dr Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
Hoogerbrugge
H
H
van Agthoven
T
T
Löwenberg
B
B
Touw
I
I
D015703:Antigens, CD / Q000032:analysis; D018941:Antigens, CD19; D000943:Antigens, Differentiation / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000473:pathology*; D018956:CD5 Antigens; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D007158:Immunologic Techniques; D007376:Interleukin-2 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology; D007621:Karyotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology*; D008233:Lymphotoxin-alpha / Q000494:pharmacology*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D015703:Antigens, CD; D018941:Antigens, CD19; D000943:Antigens, Differentiation; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D007376:Interleukin-2; D008233:Lymphotoxin-alpha; D011947:Receptors, Antigen, B-Cell; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D013755:Tetradecanoylphorbol Acetate