Are renal cell carcinoma cells able to modulate the cytotoxic effect of tumor infiltrating lymphocytes by secretion of interleukin-6?
BACKGROUND
Interleukin (IL)-6 can suppress the cisplatin-induced induction of apoptosis in renal cell carcinoma (RCC) in vitro. There are reports on IL-6 secretion by tumor cells.


METHODS
In supermatants of RCC cultures we measured IL-6 levels by a bioassay. In a videomicroscopic microcytotoxicity assay the immunomodulating effect of secreted cytokines on the cytotoxicity of tumor infiltrating lymphocytes (TIL) was studied.


RESULTS
The IL-6 concentrations in 17 supematants of healthy renal cells tended to be higher than in the supernatants of tumor cell cultures. By immunostaining we detected IL-6 in 3/6 cell cultures from healthy renal tissue, in 12/22 tumor tissue samples, and in 8/18 tumor cultures respectively. Supernatants suppressing cytotoxic activity of TIL showed higher IL-6 concentrations in tendency. Suppression of cytotoxicity could also be induced by adding discrete concentrations of IL-6.


CONCLUSIONS
IL6 secreted by tumor cells seems to be tumor protecting against cytotoxic TIL. Blocking this mechanism could be an additional approach in immunotherapy of RCC.
Steiner
T
T
Department of Urology, Friedrich-Schiller-University, Jena, Germany. steiner@landgraf.med.uni-jena.de
Junker
U
U
Wunderlich
H
H
Schubert
J
J
D017209:Apoptosis; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000473:pathology* / Q000601:surgery; D016207:Cytokines / Q000032:analysis; D003602:Cytotoxicity, Immunologic; D005452:Fluoresceins / Q000032:analysis; D005456:Fluorescent Dyes; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism*; D007680:Kidney Neoplasms / Q000276:immunology* / Q000473:pathology* / Q000601:surgery; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D018715:Microscopy, Video; D014407:Tumor Cells, Cultured
D016207:Cytokines; D005452:Fluoresceins; D005456:Fluorescent Dyes; D015850:Interleukin-6; C007740:fluorexon