Decreased IFN-gamma activity in anxiety disorders

Interferon (IFN)-gamma, in common with a number of cytokines or growth factors, strongly interacts with heparan sulphate (HS). It has been shown previously that one of the C-terminal basic clusters of amino acids (a regulatory element of IFN-gamma activity) is involved in this interaction. The structural organization of the HS domain that binds to human IFN-gamma has been investigated here. IFN-gamma-affinity chromatography of HS oligosaccharides released by either enzymic or chemical cleavage showed that the binding site is not found in a domain that is resistant to either heparinase or heparitinase or exclusively N-sulphated or N-acetylated. This led us to take a ‘footprinting’ approach in which HS was depolymerized in the presence of IFN-gamma and the cytokine-protected sequences were separated from the digested fragments. Using this strategy we consistently isolated an IFN-gamma-protected domain (IPD; approx. 10 kDa) which displayed the same affinity as full-length HS for the cytokine. Treatment of IPD with either heparinase or heparitinase strongly reduced its affinity, confirming that the high-affinity binding site encompassed a mixture of HS structural domains. Patterns of depolymerization with either enzymic or chemical agents were consistent with IPD being composed of an extended internal domain (approx. 7 kDa) which is predominantly N-acetylated and GlcA-rich, flanked by small N-sulphated oligosaccharides (mainly hexa- to octasaccharides). This is the first description of an HS protein-binding sequence with this type of molecular organization. Furthermore, using a cross-linking strategy, we demonstrated that one HS molecule bound to an IFN-gamma dimer. Together these results lead us to propose a novel model for the interaction of HS with a protein, in which two sulphated terminal sequences of the binding domain interact directly with the two IFN-gamma C-termini and bridge the two cytokine monomers through an internal N-acetyl-rich sequence.

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Role of immune interferon in the monocytic differentiation of human promyelocytic cell lines induced by leukocyte conditioned medium

Blood ◽

10.1182/blood.v66.3.583.583 ◽

1985 ◽

Vol 66 (3) ◽

pp. 583-594 ◽

Cited By ~ 24

Author(s):

ET Dayton ◽

M Matsumoto-Kobayashi ◽

B Perussia ◽

G Trinchieri

Keyword(s):

Antiviral Activity ◽

Conditioned Medium ◽

Cell Lines ◽

Gel Filtration ◽

Gamma Activity ◽

Nonspecific Esterase ◽

Monocytic Differentiation ◽

Ifn Gamma ◽

Immune Interferon ◽

Dependent Cell

Abstract Conditioned medium (CM) from lectin-stimulated human leukocytes contains factors that induce human promyelocytic cell lines to differentiate along the monocytic pathway. In this report, we show that human promyelocytic cell lines are also induced to differentiate along this pathway by immune interferon (IFN gamma). Various preparations of IFN alpha tested did not induce this differentiation. In cultures containing IFN gamma, the cells are induced to coordinately express monocyte markers and functions such as monocyte-specific surface antigens, HLA-DR antigens, nonspecific esterase, receptors for the Fc fragment of IgG, and the ability to mediate antibody-dependent cell- mediated cytotoxicity. Our data indicate that differentiation induced by IFN gamma is not secondary to an arrest of growth of promyelocytic cell lines, but rather that a proportion of cells is induced along a programmed pathway of terminal differentiation similar to that of normal monocytes. CM contains IFN gamma, but its ability to induce differentiation is greater than expected on the basis of its content of IFN gamma. Treatments at 56 degrees C or at pH 2.0, which abolish IFN gamma activity, abrogate the differentiation ability of CM. The antiviral activity and the differentiation activity contained in the CM are coeluted from gel filtration and reverse-phase columns. Monoclonal antibodies anti-IFN gamma, which completely abrogate the differentiation ability of IFN gamma and the antiviral activity in the CM, completely suppress the induction of some monocyte markers by CM, but only reduce the expression of others. When IFN gamma is added to CM, promyelocytic cell lines are induced to differentiate to a much greater extent than that induced by either IFN gamma or IFN gamma- depleted CM alone. These results show that the differentiation activity of leukocyte CM is due to the synergistic effect of IFN gamma and other factors not yet identified.

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Role of immune interferon in the monocytic differentiation of human promyelocytic cell lines induced by leukocyte conditioned medium

Blood ◽

10.1182/blood.v66.3.583.bloodjournal663583 ◽

1985 ◽

Vol 66 (3) ◽

pp. 583-594

Author(s):

ET Dayton ◽

M Matsumoto-Kobayashi ◽

B Perussia ◽

G Trinchieri

Keyword(s):

Antiviral Activity ◽

Conditioned Medium ◽

Cell Lines ◽

Gel Filtration ◽

Gamma Activity ◽

Nonspecific Esterase ◽

Monocytic Differentiation ◽

Ifn Gamma ◽

Immune Interferon ◽

Dependent Cell

Conditioned medium (CM) from lectin-stimulated human leukocytes contains factors that induce human promyelocytic cell lines to differentiate along the monocytic pathway. In this report, we show that human promyelocytic cell lines are also induced to differentiate along this pathway by immune interferon (IFN gamma). Various preparations of IFN alpha tested did not induce this differentiation. In cultures containing IFN gamma, the cells are induced to coordinately express monocyte markers and functions such as monocyte-specific surface antigens, HLA-DR antigens, nonspecific esterase, receptors for the Fc fragment of IgG, and the ability to mediate antibody-dependent cell- mediated cytotoxicity. Our data indicate that differentiation induced by IFN gamma is not secondary to an arrest of growth of promyelocytic cell lines, but rather that a proportion of cells is induced along a programmed pathway of terminal differentiation similar to that of normal monocytes. CM contains IFN gamma, but its ability to induce differentiation is greater than expected on the basis of its content of IFN gamma. Treatments at 56 degrees C or at pH 2.0, which abolish IFN gamma activity, abrogate the differentiation ability of CM. The antiviral activity and the differentiation activity contained in the CM are coeluted from gel filtration and reverse-phase columns. Monoclonal antibodies anti-IFN gamma, which completely abrogate the differentiation ability of IFN gamma and the antiviral activity in the CM, completely suppress the induction of some monocyte markers by CM, but only reduce the expression of others. When IFN gamma is added to CM, promyelocytic cell lines are induced to differentiate to a much greater extent than that induced by either IFN gamma or IFN gamma- depleted CM alone. These results show that the differentiation activity of leukocyte CM is due to the synergistic effect of IFN gamma and other factors not yet identified.

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