Soluble interleukin 2 receptors abrogate IL-2 induced activation of peripheral mononuclear cells.
Soluble interleukin 2 receptors (sIL-2R) exert a potential role in immunoregulation. We investigated the in vitro effects of sIL-2R on several interleukin 2 (IL-2)-dependent cellular events. Cytotoxicity of human rIL-2-stimulated PBMC against K562 and Daudi was correlated inversely to the concentration of sIL-2R in the culture medium during rIL-2 stimulation. sIL-2R concentrations higher than 4.0 pM produced a significant loss of cytotoxicity (P < 0.01). The effect of different sIL-2R concentrations added to cultured human PBMC on secondary sIL-2R production was tested by ELISA. Secondary sIL-2R production was abrogated by high initial sIL-2R dosages whereas low initial dosages were followed by a continuing production of secondary sIL-2R after five days of culture. Proliferation of the IL-2-dependent mouse cell line CTLL-2-was suppressed by sIL-2R added to the culture medium in a dose-dependent way. The neutralizing capacity of sIL-2R strongly depended on the initial number of CTLL set in per proliferation assay. In contrast, variation of rIL-2-concentration had no significant effect on reduction of proliferation by sIL-2R. Furthermore, preincubation of sIL-2R with rIL-2 did not enhance growth suppression. These last findings indicate that there is at least no functional interaction between sIL-2R and free IL-2, whereas an interaction of sIL-2R with the membrane-bound receptor for IL-2 seems possible.
Zorn
U
U
Department of Hematology and Oncology, Medizinische Hochschule Hannover, University Medical Center, Germany.
Dallmann
I
I
Grosse
J
J
Kirchner
H
H
Poliwoda
H
H
Atzpodien
J
J
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D007958:Leukocyte Count / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects*; D051379:Mice; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D012995:Solubility
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins