Autocrine growth factors secreted by the malignant human B-cell-line BJAB are distinct from other known cytokines.
BJAB, a EBV-negative Burkitt-like lymphoma, did not grow under suboptimal culture conditions in low concentrations of serum unless appropriate cytokines were added. A subclone of BJAB, Clone 13, however, could be kept in long-term culture under such conditions without added cytokines. This suggested that growth of BJAB-Clone 13 was supported by autocrine growth factors (AGF). In fact, the supernatant of Clone 13 stimulated growth of the parental BJAB line and showed IL-1-like activity. Of several cytokines tested only AGF and IL-1 stimulated growth of BJAB. IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, GM-CSF, TNF-alpha, LT, IFN-gamma and TGF beta did not have this effect. The IL-1-like activity was completely neutralized by anti-IL-1 alpha antibodies. In contrast, AGF-activity was not affected by anti-IL-1 alpha. Rabbit antibodies produced against fractions enriched for AGF inhibited growth of BJAB. This inhibition was overcome by Clone 13-AGF, but not by IL-1 alpha. These data suggest that Clone 13-AGF is distinct from IL-1 alpha and might be a new cytokine.
Lahm
H
H
Institute for Immunology and Genetics, German Cancer Research Center, Heidelberg.
Fischer
J R
JR
Reichert
Y
Y
Hederer
R
R
Falk
W
W
Debatin
K M
KM
Krammer
P H
PH
D000906:Antibodies; D001402:B-Lymphocytes / Q000378:metabolism*; D002999:Clone Cells / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000378:metabolism
D000906:Antibodies; D016207:Cytokines; D006133:Growth Substances; D007375:Interleukin-1