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Query: UNIPROT:P05231 (
interleukin-6
)
23,907
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The role of
interleukin-6
(
IL-6
) in the pathogenesis of toxoplasmic encephalitis (TE) was examined by using
IL-6
-targeted mutant (
IL-6
(-/-)) mice. At 4 and 8 weeks after infection with the ME49 strain of Toxoplasma gondii, significantly greater numbers of T. gondii cysts and areas of inflammation associated with tachyzoites were observed in brains of
IL-6
(-/-) mice than in those of control mice. Large areas of necrosis were observed only in brains of
IL-6
(-/-) mice. Tachyzoites were frequently detected in the areas of necrosis, suggesting that necrosis was caused by proliferation of the parasite. These results indicate that
IL-6
is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in brains of infected mice. Whereas in brains of control mice, large numbers of inflammatory cells were always observed in areas where tachyzoites were detected, in brains of
IL-6
(-/-) mice, only small numbers of inflammatory cells were observed in many areas with tachyzoites. Lymphocyte preparations isolated from brains of infected control mice had significantly higher ratios of gamma/delta T cells and CD4+ alpha/beta T cells but lower ratios of CD8+ alpha/beta T cells compared to those of infected
IL-6
(-/-) mice. There were no differences in the ratios of these T-cell subsets in spleens between these mice. The amounts of mRNA for gamma interferon (IFN-gamma) detected by reverse transcriptase PCR were significantly smaller in brains of
IL-6
(-/-) mice than in those of control mice, whereas amounts of
IL-10
mRNA were greater in the former than in the latter.
IL-6
mRNA was detected only in infected control mice. The protective activity of
IL-6
against development of TE appears to be through its ability to stimulate IFN-gamma production and induce infiltration and accumulation of different T-cell subsets in brains of infected mice.
...
PMID:Impaired resistance to the development of toxoplasmic encephalitis in interleukin-6-deficient mice. 916 72
We previously reported that in vitro culture of human peripheral blood monocytes resulted in a time-dependent differentiation into macrophages and in an enhanced capacity for producing certain cytokines [i.e., tumor necrosis factor alpha,
interleukin-6
(
IL-6
), and interferon-beta (IFN-beta)] in response to bacterial lipopolysaccharide (LPS). HIV-1 infection or gp120 treatment of monocyte/macrophages resulted in the induction of low levels of IFN-beta, which were very effective in restricting viral replication in 7-day cultured macrophages but not in freshly isolated cells. This enhanced response of macrophages was due to a higher sensitivity of these cells to the antiviral effect of IFN-beta. Consistent with this finding, 7-day cultured macrophages exhibited higher levels of type I IFN receptors than 1-day cultured monocytes. Treatment of monocyte/macrophages with gp120 also caused a marked increase in
IL-10
secretion, regardless of the differentiation state. No IL-12 secretion was detected in monocyte/macrophage cultures treated with gp120 alone. However, consistent IL-12 secretion was found in 7-day cultured macrophages primed with IFN-beta and subsequently stimulated with gp120. Macrophages responded more efficiently than monocytes to the priming effect of IFN-beta for IL-12 production. This was consistent with a stronger antiviral response against vesicular stomatitis virus by these cells as well as with a higher expression of IFN-beta receptors. The finding that the acquisition of the macrophage phenotype is associated with an increased capacity to respond to environmental signals (such as type I and type II IFNs) underlines the importance of the differentiation process for the selection of a certain repertoire of responses that may allow these cells to have important functions in vivo.
...
PMID:Induction of cytokines by HIV-1 and its gp120 protein in human peripheral blood monocyte/macrophages and modulation of cytokine response during differentiation. 922 92
Forty-one African patients suffering from clinically defined severe malaria were studied in the intensive medical care unit of the main hospital in Dakar, Senegal, West Africa. All of these individuals lived in Greater Dakar, an area of low and seasonal Plasmodium falciparum endemicity. Twenty-seven patients (mean age +/- 1 standard deviation, 19.2 +/- 12.7 years) survived this life-threatening episode, but 14 (30.8 +/- 16.2 years old) died despite initiation of adequate treatment. On the day of admission (day 0) and 3 days later, one to two blood samples (i.e., approximately 10 to 15 ml) were obtained from each subject, and different biological parameters were evaluated in the two groups. Plasma samples were tested for their content in tumor necrosis factor alpha (TNF-alpha), soluble receptors I and II for TNF-alpha (TNF-alpha sRI and TNF-alpha sRII),
interleukin-6
(
IL-6
),
IL-6
sR,
IL-10
, and IL-2 sR. The concentrations of all these cytokines and/or their receptors was significantly elevated in patient plasma samples on day 0, and it rapidly decreased in the group of individuals who survived. By comparison, the mean concentration of the same parameters decreased slowly in the group of patients who died (except for
IL-10
, which dramatically fell in all patient plasma samples soon after initiation of antimalarial treatment). The TNF-alpha sRI level remained significantly elevated among the patients who died, and the highest levels of soluble TNF-alpha sRI receptor were found among the older patients. Parasite-specific immunoglobulin M (IgM), total IgG, IgG1, IgG2, IgG3, and IgG4 were evaluated by enzyme-linked immunosorbent assay using a crude extract of a local P. falciparum isolate as antigen and human class- and subclass-specific monoclonal antibodies. Parasite-specific IgM, total IgG, and IgG1 were detectable in the plasma samples of most of these African patients, whereas IgG2 and IgG4 mean values were low. The mean level of parasite-specific IgG3 was different (P = 0.024) at day 0, i.e., before initiation of intensive medical care, between the group of the 27 surviving subjects and the group of 14 patients dying of severe malaria. As a consequence, most of the African patients who died had only trace amounts or almost no detectable level of parasite-specific IgG3 at the time of admission. In contrast, the presence of even limited IgG3 activity at day 0 was found to be associated with a significantly increased probability of recovering from severe malaria. Therefore, in our study, both an elevated level of TNF-alpha sRI and absence of IgG3 activity were of bleak prognostic significance, whereas a favorable outcome was usually observed when parasite-specific IgG3 activity was detectable. This finding was strongly suggestive of a prime role for these parasite-specific immunoglobulins in the capacity to help recovery from severe malaria.
...
PMID:Prognostic value of anti-Plasmodium falciparum-specific immunoglobulin G3, cytokines, and their soluble receptors in West African patients with severe malaria. 923 86
It has been previously reported that the production of
interleukin-6
(
IL-6
) is often enhanced in systemic lupus erythematosus (SLE). The authors examined the secretion of
IL-6
, tumour necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor, IL-1 alpha and IL-4 by B cells and monocytes from lupus patients and compared this to the production in normal controls and in rheumatoid arthritis patients.
IL-6
production was increased an average of 3.4-fold compared to that in normal subjects and 8.4-fold compared to rheumatoid arthritis patients. In SLE, a strongly positive correlation was found between the levels of
IL-6
and TNF-alpha (R = 0.8987, P = 0.002). Since production of both
IL-6
and TNF-alpha is regulated by
IL-10
, the enhancement of the production of these cytokines could reflect a defect in either
IL-10
production or responsiveness. However, spontaneous production of
IL-10
was enhanced in cultures of B cells and monocytes from lupus patients, compared to normal controls, the levels being increased 3.1- to 6-fold for monocytes and B cells, respectively. The finding of increased secretion of these cytokines implies an abnormality in
IL-10
-mediated suppression in SLE. To assess this possibility, the authors examined recombinant human
IL-10
-mediated suppression of
IL-6
production by monocytes and B cells from lupus patients, compared to normal controls, and found that whereas
IL-10
caused a concentration-dependent suppression of
IL-6
production in normal B cells and monocytes, this suppression was deficient in B cells and monocytes from lupus patients. In SLE, it therefore appears that there may be an intrinsic defect in
IL-10
-induced suppression of cytokine synthesis. This could explain the increased levels of
IL-10
and
IL-6
found in this condition, and may also be responsible for the characteristic polyclonal B-cell activation that is seen.
...
PMID:Interleukin-10 response abnormalities in systemic lupus erythematosus. 935 Feb 93
Interleukin-10 is an important cytokine that is involved in regulation of pro-inflammatory cytokines and T-cell responses. Interleukin-10 has been studied extensively in various preclinical and clinical models of inflammation. The most remarkable and consistently reproducible quality of
IL-10
is its ability to downregulate macrophage functions. This includes inhibiting the production of pro-inflammatory cytokines such TNF-alpha, Interleukin-1,
Interleukin-6
and antigen presentation by these professional antigen presenting cells. Additionally, Interleukin-10 also has effects on various other cell types of hematopoietic origin such as B-cells, neutrophils, and most importantly T-cells. Interleukin-10 has shown efficacy in several models of autoimmune disease. The present article deals with the effect of Interleukin-10 in animal models of inflammatory bowel disease and the results of phase I clinical trials in normal human volunteers and chronic active Crohn's disease patients.
...
PMID:Immunomodulation of Crohn's disease by interleukin-10. 942 29
We examined the pathogenesis of the facultative intracellular bacterium, Salmonella typhimurium in MHCII-/-, C2D knock-out mice, and wild-type C57BL/6J mice. The MHCII knock-out shortened the kinetics of animal death and reduced the dose of S. typhimurium needed to kill mice. We measured the physiological and cytokine responses of both mouse strains after S. typhimurium injection. Animal weight loss, spleen weights, liver weights, thymus weights, and serum corticosterone concentrations were comparable after injection with several doses of bacteria. The only physiological differences observed between the two strains were observed 3 days after injection of the highest dose of bacteria tested. Serum concentrations of tumor necrosis factor alpha, interleukin-2, and
interleukin-6
increased in a dose-dependent fashion irrespective of mouse MHCII expression. Therefore, even in the absence of MHCII, mice are able to mount relatively normal physiological and immunological responses. Consistent with these normal responses, an increased percentage of MHCII-/- mice, primed with a low dose of bacteria 13 days earlier, were able to survive a lethal challenge of Salmonella compared with unprimed controls. Lastly, C2D mice had significantly higher serum interleukin-10 concentrations than C57BL/6J mice 48 h after infection with all doses of S. typhimurium. C2D macrophages also secreted significantly more
IL-10
and less NO and O2- after lipopolysaccharide or phorbol ester stimulation in vitro than wild-type macrophages.
...
PMID:Salmonella infections in the absence of the major histocompatibility complex II. 950 May 16
Primary effusion lymphoma (PEL) is a distinct clinicopathologic entity associated with Kaposi's sarcoma-associated herpes virus (KSHV). Several cytokines, including
interleukin-6
(
IL-6
), basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF) may be important for survival of KS cells. However, little is known about the interaction of cytokines with KSHV-infected lymphocytes from PEL. Therefore, we investigated what cytokines were produced by KSHV-infected PEL cell lines (KS-1, BC-1, BC-2), what cytokine receptors were expressed by these cells, what response these cells had to selected cytokines, and what was the effect of
IL-6
antisense phosphorothioated oligonucleotides. Reverse transcriptase-polymerase chain reaction (RT-PCR) and protein studies showed that these three cell lines produced
IL-10
,
IL-6
, and the receptors for
IL-6
. The granulocyte macrophage colony-stimulating factor (GM-CSF), IL-1beta, IL-8, IL-12, bFGF, PDGF, and c-kit transcripts were not detected in the cell lines. High levels (0.7 to 5 ng/mL/10(6) cells/48 hours) of
IL-6
protein were consistently detected in supernatants of the cell lines by enzyme-linked immunosorbent assay (ELISA) tests. In clonogenic assays, interferon-alpha (IFN-alpha) and IFN-gamma suppressed the clonal growth of the PEL cells, but GM-CSF, IL-4,
IL-6
, IL-8,
IL-10
, and oncostatin M did not change it. We examined for several autocrine loops that have been suggested to occur in KS. Experiments using antisense oligonucleotides showed that the clonal growth of KS-1 and BC-1 was nearly 100% inhibited by
IL-6
antisense oligonucleotides (10 micromol/L), but not at all by either oligonucleotides (</=10 micromol/L) to
IL-6
sense,
IL-6
scrambled, viral
IL-6
(vIL-6) antisense, or
IL-10
antisense. Furthermore, the
IL-6
antisense oligonucleotides had no effect on two B-cell lymphoma cell lines, which were not infected with KSHV. Addition of
IL-6
antibody did not inhibit clonal growth of any of the cell lines. Taken together, we have defined the cytokines and their receptors expressed on PEL cells and have found that these cells synthesized
IL-6
and
IL-6
receptors; interruption of this pathway by
IL-6
antisense oligonucleotides specifically prevented the growth of these cells. These findings will offer potential new therapeutic strategies for PEL.
...
PMID:Mechanisms of growth control of Kaposi's sarcoma-associated herpes virus-associated primary effusion lymphoma cells. 951 48
The potential contribution made by the inflammatory cytokines,
interleukin-6
(
IL-6
) and tumour necrosis factor-alpha (TNF-alpha) to the adjuvant activity of aluminium hydroxide gels (Alum) or Freund's complete adjuvant (FCA) was studied by comparing the immunological responses of
IL-6
- or TNF receptor 1- (p55; TNFR-1) deficient mice with immunocompetent control mice. While both TNFR-1- and
IL-6
-deficient mice primed with ovalbumin (OVA) prepared in either Alum or FCA produced similar IgG.1 responses in comparison to control mice, the pattern of T-helper type 1- (Th1) dependent IgG2a production was significantly altered. In TNFR-1-deficient mice, IgG2a responses were greater than in control mice when FCA, but not when Alum, was used as an adjuvant. Correspondingly, spleen cells from FCA-inoculated TNFR-1-deficient mice restimulated with antigen in vitro produced higher Th1 cytokine (interferon-gamma; IFN-gamma) levels with no alteration in Th2 cytokine (IL-4; IL-5,
IL-6
and
IL-10
) production in comparison with wild-type mice. Higher levels of IgG2a were also detected in
IL-6
-deficient mice compared with wild-type mice following inoculation with OVA prepared in either FCA or in Alum. Furthermore, analysis of cytokine production by spleen cells revealed that both Th1 and Th2 cytokine production was higher in
IL-6
-deficient mice compared with control mice. As the majority of the effects of TNF-alpha are mediated via TNFR-1, we conclude that this cytokine inhibits the adjuvant activities of FCA. Furthermore, the results also imply that immunopotentiating effects of FCA or Alum adjuvant are both inhibited by
IL-6
.
...
PMID:Neither interleukin-6 nor signalling via tumour necrosis factor receptor-1 contribute to the adjuvant activity of Alum and Freund's adjuvant. 953 17
The soluble
Interleukin-6
receptor (sIL-6R) is capable of conferring the
Interleukin-6
(
IL-6
) signal onto cells lacking the gp80 ligand binding protein. Here we investigate the release of sIL-6R from T-cells. After 2 h stimulation with PMA, a release of sIL-6R from peripheral human T-cells was observed which was insensitive to the protein synthesis inhibitor cycloheximide. This release was accompanied by a decrease of membrane-bound (mb) IL-6R. After 24 h, however, the observed sIL6-R release did prove to be sensitive to cycloheximide. These results suggest that both shedding and denovo-synthesis may be responsible for the PMA-induced sIL-6R release. In contrast to PMA, neither anti-CD3, a positive, nor
IL-10
, a negative regulator of
IL-6
release from T-cells affected the production of the sIL-6R. The differential regulation of sIL-6R and
IL-6
production by T-cells might be relevant for the immunomodulatory potential of the sIL-6R with respect to the interaction of T- and non-T-cells.
...
PMID:Release of the soluble interleukin-6 receptor from human T-cells. 956 17
The 70-kDa recombinant Candida albicans heat shock protein (CaHsp70) and its 21-kDa C-terminal and 28-kDa N-terminal fragments (CaHsp70-Cter and CaHsp70-Nter, respectively) were studied for their immunogenicity, including proinflammatory cytokine induction in vitro and in vivo, and protection in a murine model of hematogenous candidiasis. The whole protein and its two fragments were strong inducers of both antibody (Ab; immunoglobulin G1 [IgG1] and IgG2b were the prevalent isotypes) and cell-mediated immunity (CMI) responses in mice. CaHsp70 preparations were also recognized as CMI targets by peripheral blood mononuclear cells of healthy human subjects. Inoculation of CaHsp70 preparations into immunized mice induced rapid production of
interleukin-6
(
IL-6
) and tumor necrosis factor alpha, peaking at 2 to 5 h and declining within 24 h. CaHsp70 and CaHsp70-Cter also induced gamma interferon (IFN-gamma), IL-12, and
IL-10
but not IL-4 production by CD4+ lymphocytes cocultured with splenic accessory cells from nonimmunized mice. In particular, the production of IFN-gamma was equal if not superior to that induced in the same cells by whole, heat-inactivated fungal cells or the mitogenic lectin concanavalin A. In immunized mice, however, IL-4 but not IL-12 was produced in addition to IFN-gamma upon in vitro stimulation of CD4+ cells with CaHsp70 and CaHsp70-Cter. These animals showed a decreased median survival time compared to nonimmunized mice, and their mortality was strictly associated with organ invasion by fungal hyphae. Their enhanced susceptibility was attributable to the immunization state, as it did not occur in congenitally athymic nude mice, which were unable to raise either Ab or CMI responses to CaHsp70 preparations. Together, our data demonstrate the elevated immunogenicity of CaHsp70, with which, however, no protection against but rather some enhancement of Candida infection seemed to occur in the mouse model used.
...
PMID:A 70-kilodalton recombinant heat shock protein of Candida albicans is highly immunogenic and enhances systemic murine candidiasis. 957 2
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