Functional characterization of murine cell lines expressing high, intermediate, or negative levels of surface receptors for interferon-gamma.
Using radioiodinated murine interferon-gamma (IFN-gamma), various cell lines were analyzed for their capacity to bind IFN-gamma and to respond to its biological activity as measured by activation of the 2',5'-oligoadenylate (2-5A) synthetase, induction of the antiviral activity, and inhibition of [3H]thymidine uptake. A T-cell lymphoma, EL-4, was found to express relatively high number of specific membrane receptors for IFN-gamma (60,000/cell) with a dissociation constant of around 9 X 10(-10) M. By contrast, a fibroblast cell line, K-BALB, transformed by the Kirstein murine sarcoma virus, was found negative for binding of radioiodinated IFN-gamma, even in the presence of high ligand concentrations. Other cell lines displayed numbers of receptors varying between 650 to 20,000 binding sites/cell with KD ranging between 5 X 10(-9) to 9 X 10(-10) M. When incubated with EL-4 expressing high levels of specific receptors, IFN-gamma caused stimulation of cell growth, but not resistance to viral (vesicular stomatitis virus) infection and expression of 2-5A synthetase. By contrast, when L1210 and TS/A cells, expressing intermediate levels of specific receptors, were incubated with IFN-gamma, inhibition of cell growth, induction of antiviral resistance and activation of 2-5A synthetase was observed. Finally, K-BALB cells, lacking specific receptors for IFN-gamma, were completely unsensitive to its biological activity. The present system could represent a useful model for the characterization of the interaction of IFN-gamma with target cells at molecular levels.
Fassio
A
A
Institute of Microbiology, Medical School, University of Torino, Italy.
Gariglio
M
M
Cofano
F
F
Cavallo
G
G
Landolfo
S
S
D015088:2',5'-Oligoadenylate Synthetase / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D002472:Cell Transformation, Viral / Q000187:drug effects; D004790:Enzyme Induction; D007371:Interferon-gamma / Q000378:metabolism* / Q000494:pharmacology; D007939:Leukemia L1210 / Q000378:metabolism; D051379:Mice; D011971:Receptors, Immunologic / Q000032:analysis*; D017471:Receptors, Interferon
D011971:Receptors, Immunologic; D017471:Receptors, Interferon; D007371:Interferon-gamma; D015088:2',5'-Oligoadenylate Synthetase