scholarly journals Regulation of cytokine production by soluble CD23: costimulation of interferon gamma secretion and triggering of tumor necrosis factor alpha release.

1994 ◽  
Vol 180 (3) ◽  
pp. 1005-1011 ◽  
Author(s):  
M Armant ◽  
H Ishihara ◽  
M Rubio ◽  
G Delespesse ◽  
M Sarfati

Soluble CD23 (sCD23) has multiple IgE-independent biological activities. In the present study, we examined the regulatory effect of sCD23 on cytokine production by human peripheral blood mononuclear cells (PBMC). We show that sCD23 enhances by about 80-fold the interleukin 2 (IL-2)-induced interferon gamma (IFN-gamma) production and by about 10-fold the response to IL-12. This potentiating activity is time and dose dependent and is not associated with a significant effect on DNA synthesis. The sCD23 costimulatory activity for IFN-gamma synthesis is drastically reduced in monocyte-depleted PBMC, suggesting that monocytes may be the target for sCD23. This hypothesis was supported by the following observations. First, sCD23 alone is a potent inducer of tumor necrosis factor alpha (TNF-alpha) production by PBMC and this effect disappears after monocyte depletion. The triggering of TNF-alpha release is specifically inhibited by neutralizing anti-CD23 monoclonal antibody (mAb). In addition, IL-2 and IL-12 synergize with sCD23 to induce TNF-alpha production. Second, sCD23 triggers the release of other inflammatory mediators such as IL-1 alpha, IL-1 beta, and IL-6. Finally, TNF-alpha production in response to IL-2 and sCD23 precedes IFN-gamma and IFN-gamma secretion is significantly inhibited by anti-TNF-alpha mAb, indicating that the sCD23 costimulatory signal for IFN-gamma production may be partially mediated by TNF-alpha release. It is proposed that sCD23 is a proinflammatory cytokine that, in addition, may play an important role in the control of the immune response via the enhancement of IFN-gamma production.

1991 ◽  
Vol 100 (4) ◽  
pp. 833-840
Author(s):  
G. Poli ◽  
C. Sorio ◽  
G. Berton

Labelling of cells with [3H]myristic acid and analysis of labelled proteins by SDS-PAGE and fluorography, enabled the identification of a limited number of myristoylated proteins in human monocytes and monocyte-derived macrophages. In human monocytes, cultivated for one to three days, major myristoylated proteins observed were of 18 kDa, 44 kDa, 60–62 kDa, 90 kDa, and a doublet of 38–40 kDa. Differentiation of monocytes to macrophages by in vitro cultivation was accompanied by a selective decrease in the 60–62 kDa protein. Cultivation of the cells in the presence of the macrophage-activating cytokines interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), prevented the decrease in the expression of the 60–62 kDa myristoylated protein. The effect of cytokines was observed when monocytes were treated with IFN-gamma or TNF-alpha for 24 or 48 h and protein myristoylation analyzed at day four of culture. Maintenance of monocytes in culture for up to nine days in the presence of cytokines prevented the decrease in the expression of the 60–62 kDa myristoylated protein. IFN-gamma had additional effects on myristoylation of macrophage proteins. Treatment of monocytes with IFN-gamma for a few hours caused the induction of a 66 kDa protein. Induction of this myristoylated protein by IFN-gamma was time-dependent and peaked at six hours. Analysis of the subcellular distribution of the 66 kDa protein induced by IFN-gamma showed that, analogously to other myristoylated proteins, most of it was associated with cell membranes.(ABSTRACT TRUNCATED AT 250 WORDS)


1991 ◽  
Vol 261 (4) ◽  
pp. L315-L321 ◽  
Author(s):  
J. N. Allen ◽  
D. J. Herzyk ◽  
M. D. Wewers

To study the role of microtubules in cytokine production, the effect of the microtubule depolymerizing agent colchicine on lipopolysaccharide endotoxin (LPS)-induced interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) release by blood monocytes and alveolar macrophages were examined. Immunofluorescence microscopy demonstrated that LPS resulted in the appearance of microtubule-containing cytoplasmic appendages and that colchicine, which resulted in microtubule disruption in monocytes, blocked appendage formation. Colchicine resulted in approximately 50% increase in LPS-induced IL-1 beta release and a 50% decrease in LPS-induced TNF-alpha release by human monocytes at all doses of LPS tested. Although colchicine resulted in a statistically significant increase in LPS-stimulated human alveolar macrophage IL-1 beta release, the increase was not as great as that observed with monocytes. Northern blot analysis suggested that the colchicine effect occurs pretranslationally because colchicine caused an increase in LPS-stimulated IL-1 beta mRNA levels and a decrease in TNF-alpha mRNA levels. These results suggest that microtubules contribute to the regulation of endotoxin-stimulated mononuclear phagocyte cytokine production and that this regulation differs significantly between IL-1 beta and TNF-alpha.


Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1392-1397 ◽  
Author(s):  
AA te Velde ◽  
RJ Huijbens ◽  
K Heije ◽  
JE de Vries ◽  
CG Figdor

Monocytes activated by lipopolysaccharide (LPS) and interferon gamma (IFN gamma) rapidly secrete a number of monokines with different functional properties. Interleukin–4 (IL–4), a T-cell derived cytokine, has been shown to reduce the production of monokines with cytostatic activity for tumor cells, chemotactic activity for monocytes, and factors that stimulate thymocyte proliferation. This latter activity is mediated by a number of monokines like IL–1, tumor necrosis factor alpha (TNF alpha), and IL–6. To elucidate which cytokines produced by monocytes are controlled by IL–4, we tested the effect of IL–4 on the secretion of IL–1 alpha, IL–1 beta, TNF alpha, and IL–6 induced by LPS or IFN gamma. IL–4 was found to inhibit the secretion of IL–1 beta and TNF alpha by activated monocytes almost 100%. The secretion of IL–6 was found to be reduced 70% to 85% in the presence of IL–4, whereas there was no effect on the secretion of IL–1 alpha (IL–1 alpha is mainly cell- associated). Time-course experiments demonstrate that IL–4 reduces the secretion of monokines for a prolonged period of time (greater than 40 hours). The reduced secretion of IL–1 beta and TNF alpha was specifically induced by IL–4 because anti-IL–4 antiserum completely restored normal monokine production. These data suggest that IL–4 plays a role in the regulation of immune responses by reducing the production of functionally important monokines.


Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1392-1397 ◽  
Author(s):  
AA te Velde ◽  
RJ Huijbens ◽  
K Heije ◽  
JE de Vries ◽  
CG Figdor

Abstract Monocytes activated by lipopolysaccharide (LPS) and interferon gamma (IFN gamma) rapidly secrete a number of monokines with different functional properties. Interleukin–4 (IL–4), a T-cell derived cytokine, has been shown to reduce the production of monokines with cytostatic activity for tumor cells, chemotactic activity for monocytes, and factors that stimulate thymocyte proliferation. This latter activity is mediated by a number of monokines like IL–1, tumor necrosis factor alpha (TNF alpha), and IL–6. To elucidate which cytokines produced by monocytes are controlled by IL–4, we tested the effect of IL–4 on the secretion of IL–1 alpha, IL–1 beta, TNF alpha, and IL–6 induced by LPS or IFN gamma. IL–4 was found to inhibit the secretion of IL–1 beta and TNF alpha by activated monocytes almost 100%. The secretion of IL–6 was found to be reduced 70% to 85% in the presence of IL–4, whereas there was no effect on the secretion of IL–1 alpha (IL–1 alpha is mainly cell- associated). Time-course experiments demonstrate that IL–4 reduces the secretion of monokines for a prolonged period of time (greater than 40 hours). The reduced secretion of IL–1 beta and TNF alpha was specifically induced by IL–4 because anti-IL–4 antiserum completely restored normal monokine production. These data suggest that IL–4 plays a role in the regulation of immune responses by reducing the production of functionally important monokines.


1992 ◽  
Vol 175 (2) ◽  
pp. 405-413 ◽  
Author(s):  
F P Nestel ◽  
K S Price ◽  
T A Seemayer ◽  
W S Lapp

In this report we have investigated macrophage (M phi) activity and tumor necrosis factor alpha (TNF-alpha) production during graft-vs.-host disease (GVHD). TNF-alpha production by M phi requires two signals: priming of M phi by interferon followed by triggering of TNF-alpha production and release by lipopolysaccharide (LPS). The state of M phi activation was examined in nonirradiated B6AF1 recipient mice injected with either 60 x 10(6) (acute GVHD) or 30 x 10(6) (nonlethal GVHD) parental B6 lymphoid cells. During the early phase of acute GVHD, administration of normally sublethal amounts of LPS-triggered release of significant amounts of TNF-alpha into the serum resulting in death of the animals within 36 h. Normal animals treated with the same dose of LPS neither died nor produced detectable amounts of serum TNF-alpha. In vitro studies demonstrated that M phi were primed during GVHD. The level of M phi priming was greater during acute GVHD than nonlethal GVHD since 100-fold less LPS was required to trigger killing of a TNF-alpha-sensitive cell line by M phi from acute GVHD animals. The amount of TNF-alpha released into the serum after LPS injection increased during the course of the GVHD and was significantly greater in acute GVH-reactive mice. Endogenous LPS was detected in the serum of acute GVH-reactive animals coincident with the onset of mortality. The data provide evidence that during GVHD M phi are primed as a result of the allogeneic reaction and that endogenous LPS therefore triggers M phi production of TNF-alpha resulting in the symptoms characteristic of acute GVHD.


1994 ◽  
Vol 179 (3) ◽  
pp. 841-848 ◽  
Author(s):  
R González-Amaro ◽  
C García-Monzón ◽  
L García-Buey ◽  
R Moreno-Otero ◽  
J L Alonso ◽  
...  

Tumor necrosis factor alpha (TNF-alpha) is a multifunctional cytokine that has an important role in the pathogenesis of inflammation, cachexia, and septic shock. Although TNF-alpha is mainly produced by macrophages, there is evidence regarding TNF-alpha production by cells that are not derived from bone marrow. TNF-alpha production by normal and inflamed human liver was assessed at both mRNA and protein levels. Using a wide panel of novel anti-TNF-alpha monoclonal antibodies and a specific polyclonal antiserum, TNF-alpha immunoreactivity was found in hepatocytes from patients chronically infected with either hepatitis B virus (HBV) or hepatitis C virus. Minimal TNF-alpha immunoreactivity was detected in the mononuclear cell infiltrate and Kupffer cells. In situ hybridization experiments using a TNF-alpha RNA probe showed a significant expression of TNF-alpha mRNA in hepatocytes, Kupffer cells, and some infiltrating mononuclear cells. By contrast, TNF-alpha was detected at low levels in liver biopsies from normal individuals or patients with alcoholic liver disease and low expression of TNF-alpha mRNA was observed in these specimens. Transfection of HepG2 hepatoblastoma cells with either HBV genome or HBV X gene resulted in induction of TNF-alpha expression. Our results demonstrate that viral infection induces, both in vivo and in vitro, TNF-alpha production in hepatocytes, and indicate that the HBV X protein may regulate the expression of this cytokine. These findings suggest that TNF-alpha may have an important role in human liver diseases induced by viruses.


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