scholarly journals Legionella pneumophila Evades Gamma Interferon-Mediated Growth Suppression through Interleukin-10 Induction in Bone Marrow-Derived Macrophages

2005 ◽  
Vol 73 (5) ◽  
pp. 2709-2717 ◽  
Author(s):  
Sadako Yoshizawa ◽  
Kazuhiro Tateda ◽  
Tetsuya Matsumoto ◽  
Fumio Gondaira ◽  
Shuichi Miyazaki ◽  
...  

ABSTRACT We examined the roles of Th1-Th2 cytokine cross talk in Legionella pneumophila-infected bone marrow-derived (BM) macrophages in the presence of costimulation with interleukin-12 (IL-12) and IL-18. Treatment with gamma interferon (IFN-γ) alone or treatment with IL-12 in combination with IL-18 resulted in a 3- or 2-log reduction in bacterial numbers, respectively, in BM macrophages, whereas treatment with IL-12 or IL-18 alone had no effect. Significant amounts of IFN-γ were detected in the culture supernatants of infected macrophages stimulated with IL-12 and IL-18 in combination but not independently. Neutralization of IFN-γ by antibody completely abolished the growth inhibitory effects of IL-12 and IL-18. Interestingly, higher infectivity ratios of L. pneumophila or the addition of increasing concentrations of heat-killed bacteria (HKB) suppressed the production of IFN-γ, which resulted in the increased intracellular growth of bacteria. Significant amounts of IL-10 were detected in culture supernatants when Legionella-infected macrophages were cocultured with HKB. Furthermore, neutralization of IL-10 by antibody resulted in an increase in IFN-γ production by infected BM macrophages when cocultured with HKB. Treatment of HKB with trypsin but not polymyxin B attenuated the growth-promoting effects of HKB, suggesting the involvement of a protein component(s) in regulation of the growth of L. pneumophila. These findings demonstrate a crucial role of Th1-Th2 cross talk in L. pneumophila-infected BM macrophages. Our results also suggest that L. pneumophila modulates the cytokine balance from IFN-γ-driven Th1 to more Th2 responses, likely through the induction of IL-10 by a bacterial protein component(s). These data provide new insights not only into the cellular mechanisms of Th1-Th2 cross talk in Legionella-infected macrophages but also into the pathogenesis of L. pneumophila pneumonia in humans.

2004 ◽  
Vol 72 (4) ◽  
pp. 1974-1982 ◽  
Author(s):  
M. S. Khalifeh ◽  
J. R. Stabel

ABSTRACT Gamma interferon (IFN-γ) plays a significant role in the control of mycobacterial infections, including Mycobacterium avium subsp. paratuberculosis. However, the contribution of other immunoregulatory cytokines, such as interleukin-10 (IL-10) and transforming growth factor β (TGF-β), in Johne's disease has not been investigated as yet. In this study, we examined the effects of in vivo and in vitro infection with M. avium subsp. paratuberculosis on the production of IFN-γ, IL-10, and TGF-β by peripheral blood mononuclear cells (PBMC). We also examined the effects of exogenous IFN-γ, IL-10, and TGF-β on M. avium subsp. paratuberculosis survival in the cell cultures. PBMC obtained from naturally infected cows, regardless of their disease status, specifically upregulated IL-10 and TGF-β in culture supernatants in response to stimulation with live M. avium subsp. paratuberculosis. Nonstimulated PBMC recovered from subclinically infected animals secreted the lowest levels of TGF-β, but after stimulation with live M. avium subsp. paratuberculosis, TGF-β levels in the culture supernatants increased to levels similar to that produced by PBMC from healthy animals. The numbers of viable M. avium subsp. paratuberculosis recovered from cultures from naturally infected animals were higher than those from healthy cows after in vitro infection with M. avium subsp. paratuberculosis. The addition of exogenous IL-10 and TGF-β to PBMC isolated from healthy cows inhibited the bactericidal activity of these cells as evidenced by the increased number of viable M. avium subsp. paratuberculosis recovered from these cultures compared to cell cultures containing medium alone. These data suggest important immune regulatory roles for IL-10 and TGF-β during infection with M. avium subsp. paratuberculosis that may be directly related to their effects on macrophage activation and killing of M. avium subsp. paratuberculosis.


2000 ◽  
Vol 68 (12) ◽  
pp. 7162-7165 ◽  
Author(s):  
Frederic Ganapamo ◽  
Vida A. Dennis ◽  
Mario T. Philipp

ABSTRACT Lymph node (LN) cells from C3H/HeJ mice (Lyme disease susceptible) infected for 1 week with Borrelia burgdorferi strain JD1 produced higher levels of gamma interferon (IFN-γ) when stimulated in vitro with B. burgdorferi spirochetes than equivalent cells from B. burgdorferi-infected C57BL/6J mice (disease resistant). The interleukin-10 (IL-10) levels were comparable in the two strains, whereas the IL-4 levels were below detection limits.B. burgdorferi-stimulated LN cells from C57BL/6J mice produced significantly higher levels of IFN-γ in the presence of neutralizing anti-IL-10 antibody than cells cultured with B. burgdorferi alone. No effect of IL-10 neutralization on IFN-γ production by LN cells from C3H/HeJ mice was observed. Neutralizing antibody to IFN-γ had no effect on the production of IL-10 by LN cells from C57BL/6J mice. A slight decrease in IL-10 production was detected in culture supernatants of equivalent cells from C3H/HeJ mice. The differential effect of IL-10 on IFN-γ production in C57BL/6J and C3H/HeJ mice suggests that IL-10 is probably involved in the regulation of IFN-γ production by LN cells during infection and may be at the root of the differential susceptibility to Lyme arthritis in these two strains of mice.


2006 ◽  
Vol 75 (3) ◽  
pp. 1167-1176 ◽  
Author(s):  
Shu-Rung Chang ◽  
Kung-Jiun Wang ◽  
Yan-Feng Lu ◽  
Lii-Jia Yang ◽  
Wei-Jie Chen ◽  
...  

ABSTRACT Though it is well established that gamma interferon (IFN-γ) is crucial to the early innate defense of murine listeriosis, its sources remain controversial. In this study, intracellular cytokine staining of IFN-γ-expressing splenocytes early after Listeria monocytogenes infection revealed that NK1.1+, CD11c+, CD8+ T, and CD4+ T cells expressed IFN-γ 24 h after infection. Contrary to the previous report, most IFN-γ+ dendritic cells (DC) were CD8α− DC. Unexpectedly, almost all CD11c+ IFN-γ-expressing cells also expressed NK1.1. These NK1.1+ CD11c+ cells represented primary IFN-γ-expressing cells after infection. In situ studies showed these NK1.1+ CD11c+ cells were recruited to the borders of infectious foci and expressed IFN-γ. A significant NK1.1+ CD11c+ population was found in uninfected spleen, lymph node, blood, and bone marrow cells. And its number increased significantly in spleen, lymph node, and bone marrow after L. monocytogenes infection. Using interleukin-12 (IL-12) p40−/− mice, IFN-γ expression was found to be largely IL-12 p40 dependent, and the number of IFN-γ-expressing cells was only about one-third of that of wild-type mice. Moreover, the IFN-γ expression was absolutely dependent on live L. monocytogenes infection, as no IFN-γ was detected after inoculation of heat-killed L. monocytogenes. Our findings not only provide an insight into IFN-γ expression after in vivo infection but may also change the current perceptions of DC and natural killer cells.


2001 ◽  
Vol 69 (9) ◽  
pp. 5249-5263 ◽  
Author(s):  
Tushar K. Varma ◽  
Tracy E. Toliver-Kinsky ◽  
Cheng Y. Lin ◽  
Aristides P. Koutrouvelis ◽  
Joan E. Nichols ◽  
...  

ABSTRACT Endotoxin (lipopolysaccharide [LPS]) tolerance is a state of altered immunity characterized, in part, by suppression of LPS-induced gamma interferon (IFN-γ) expression. However, the cellular mediators regulating LPS-induced production of IFN-γ in normal mice and the effect of LPS tolerance on these mediators has not been well characterized. Our studies show that macrophage dysfunction is the primary factor causing suppressed IFN-γ expression in LPS-tolerant mice. Specifically, LPS-tolerant macrophages have a markedly impaired ability to induce IFN-γ secretion by T cells and NK cells obtained from either control or LPS-tolerant mice. However, T cells and NK cells isolated from LPS-tolerant mice produce normal levels of IFN-γ when cocultured with control macrophages or exogenous IFN-γ-inducing factors. Assessment of important IFN-γ-regulating factors showed that interleukin-12 (IL-12) and costimulatory signals provided by IL-15, IL-18, and CD86 are largely responsible for LPS-induced IFN-γ expression in control mice. IL-10 is an inhibitor of IFN-γ production in both the control and LPS-tolerant groups. Expression of IL-12 and the IL-12 receptor β1 (IL-12Rβ1) and IL-12Rβ2 subunits are suppressed in the spleens of LPS-tolerant mice. LPS-tolerant splenocytes also exhibit decreased production of IL-15 and IL-15Rα. However, expression of IL-18 and the B7 proteins CD80 and CD86 are unchanged or increased compared to controls after induction of LPS tolerance. CD28, a major receptor for B7 proteins, is also increased in the spleens of LPS-tolerant mice. Expression of the inhibitory cytokine IL-10 and the IL-10R are sustained after induction of LPS tolerance. These data show that suppression of IFN-γ production in LPS-tolerant mice is largely due to macrophage dysfunction and provide insight into the cellular alterations that occur in LPS tolerance. This study also better defines the factors that mediate LPS-induced IFN-γ production in normal mice.


2001 ◽  
Vol 69 (10) ◽  
pp. 6382-6390 ◽  
Author(s):  
Jane C. Deng ◽  
Kazuhiro Tateda ◽  
Xianying Zeng ◽  
Theodore J. Standiford

ABSTRACT Gamma interferon (IFN-γ) and T1-phenotype immune responses are important components of host defense against a variety of intracellular pathogens, including Legionella pneumophila. The benefit of intrapulmonary adenovirus-mediated IFN-γ gene therapy was investigated in a nonlethal murine model of experimental L. pneumophilapneumonia. Intratracheal (i.t.) administration of 106 CFU of L. pneumophila induced the expression of T1 phenotype cytokines, such as IFN-γ and interleukin-12 (IL-12). Natural killer cells were identified as the major cellular source of IFN-γ. To determine if enhanced expression of IFN-γ in the lung could promote pulmonary clearance of L. pneumophila, we i.t. administered 5 × 108 PFU of a recombinant adenovirus vector containing the murine IFN-γ cDNA (AdmIFN-γ) concomitant with L. pneumophila. We observed a 10-fold decrease in lung bacterial CFU at day 2 in the AdmIFN-γ-treated group compared to controls (P < 0.01). Alveolar macrophages isolated from AdmIFN-γ-treated animals displayed enhanced killing of intracellular L. pneumophila organisms ex vivo. Similar improvements in bacterial clearance were observed with i.t. recombinant IFN-γ treatment. The transient transgenic expression of IL-12, a known inducer of IFN-γ and promoter of T1-type immune responses, resulted in more modest improvement in bacterial clearance (sixfold reduction;P < 0.05). These results demonstrate that, even in immunocompetent hosts, exogenous administration or transient transgenic expression of IFN-γ, and to a lesser extent IL-12, may be of potential therapeutic benefit in the treatment of patients withLegionella pneumonia.


2001 ◽  
Vol 69 (6) ◽  
pp. 3605-3610 ◽  
Author(s):  
Sheldon Salins ◽  
Catherine Newton ◽  
Ray Widen ◽  
Thomas W. Klein ◽  
Herman Friedman

ABSTRACT Gamma interferon (IFN-γ), a pleiotropic cytokine, is now known to be produced by macrophages as well as by NK cells, γδ cells, and activated T cells. The autocrine biological functions of IFN-γ on the macrophage include the upregulation of major histocompatibility complex MHC class II and the activation to an antiviral state. In this study, the production of IFN-γ by macrophages was demonstrated to correspond to antibacterial activity. Legionella pneumophilareplicates intracellularly in thioglycolate (TG)-elicited macrophages (TG-macrophages) from A/J mice, while TG-macrophages from BALB/c mice restrict bacterial growth after an initial period of growth. BALB/c TG-macrophages were shown to express IFN-γ mRNA at 24 and 28 h, which corresponded to the initiation of anti-L. pneumophilaactivity. Moreover, IFN-γneutralization by antibody treatment of the cultures resulted in increased L. pneumophila growth in the macrophages. In contrast, no IFN-γ mRNA was expressed in TG-macrophages from A/J mice, where L. pneumophila grew unrestricted. As would be expected, IFN-γ treatment decreased bacterial growth. An IFN-γ-mediated antibacterial activity was, however, inducible in A/J macrophages by the addition of interleukin-12 following L. pneumophila infection. Thus, autocrine IFN-γ is involved in anti-L. pneumophila activity associated with different growth patterns and appears to be important during intracellular infection.


2008 ◽  
Vol 15 (8) ◽  
pp. 1171-1175 ◽  
Author(s):  
Tjitske de Boer ◽  
Jaap T. van Dissel ◽  
Taco W. J. Kuijpers ◽  
Guus F. Rimmelzwaan ◽  
Frank P. Kroon ◽  
...  

ABSTRACT To investigate whether protective immune responses can be induced in the absence of normal interleukin-12/23/gamma interferon (IL-12/23/IFN-γ) axis signaling, we vaccinated with the seasonal influenza virus subunit vaccine two patients with complete IL-12/23 receptor β1 (IL-12/23Rβ1) deficiencies, two patients with partial IFN-γ receptor I (pIFN-γRI) deficiencies, and five healthy controls. Blood samples were analyzed before, 7 days after, and 28 days after vaccination. In most cases, antibody titers reached protective levels. Moreover, although T-cell responses in patients were lower than those observed in controls, significant influenza virus-specific T-cell proliferation, IFN-γ production, and numbers of IFN-γ-producing cells were found in all patients 7 days after the vaccination. Interestingly, influenza virus-specific IFN-γ responses were IL-12/23 independent, in striking contrast to mycobacterium-induced IFN-γ production. In conclusion, influenza virus vaccination induces IL-12/23-independent IFN-γ production by T cells and can result in sufficient humoral protection in both IL-12/23Rβ1- and pIFN-γRI-deficient individuals.


2003 ◽  
Vol 71 (4) ◽  
pp. 2002-2008 ◽  
Author(s):  
Irma Aguilar-Delfin ◽  
Peter J. Wettstein ◽  
David H. Persing

ABSTRACT We examined the role of the cytokines gamma interferon (IFN-γ) and interleukin-12 (IL-12) in the model of acute babesiosis with the WA1 Babesia. Mice genetically deficient in IFN-γ-mediated responses (IFNGR2KO mice) and IL-12-mediated responses (Stat4KO mice) were infected with the WA1 Babesia, and observations were made on the course of infection and cytokine responses. Levels of IFN-γ and IL-12 in serum increased 24 h after parasite inoculation. The augmented susceptibility observed in IFNGR2KO and Stat-4KO mice suggests that the early IL-12- and IFN-γ-mediated responses are involved in protection against acute babesiosis. Resistance appears to correlate with an increase in nitric oxide (NO) production. In order to assess the contribution of different cell subsets to resistance against the parasite, we also studied mice lacking B cells, CD4+ T cells, NK cells, and macrophages. Mice genetically deficient in B lymphocytes or CD4+ T lymphocytes were able to mount protective responses comparable to those of immunosufficient mice. In contrast, in vivo depletion of macrophages or NK cells resulted in elevated susceptibility to the infection. Our observations suggest that a crucial part of the response that protects from the pathogenic Babesia WA1 is mediated by macrophages and NK cells, probably through early production of IL-12 and IFN-γ, and induction of macrophage-derived effector molecules like NO.


2002 ◽  
Vol 70 (10) ◽  
pp. 5695-5705 ◽  
Author(s):  
Peter L. W. Yun ◽  
Arthur A. DeCarlo ◽  
Charles Collyer ◽  
Neil Hunter

ABSTRACT Interleukin 12 (IL-12) is an efficient inducer and enhancer of gamma interferon (IFN-γ) production by both resting and activated T cells. There is evidence that human monocytes exposed to IFN-γ have enhanced ability to produce IL-12 when stimulated with lipopolysaccharide (LPS). In this study, it was demonstrated that LPS from the oral periodontal pathogen Porphyromonas gingivalis stimulated monocytes primed with IFN-γ to release IL-12, thereby enhancing IFN-γ accumulation in T-cell populations. P. gingivalis LPS was shown to enhance IL-12 induction of IFN-γ in T cells in a manner independent from TNF-α contribution. The levels of T-cell IL-12 receptors were not affected by P. gingivalis LPS and played only a minor role in the magnitude of the IFN-γ response. These data suggest that LPS from P. gingivalis establishes an activation loop with IL-12 and IFN-γ with potential to augment the production of inflammatory cytokines in relation to the immunopathology of periodontitis. We previously reported that the major cysteine proteinases (gingipains) copurifying with LPS in this organism were responsible for reduced IFN-γ accumulation in the presence of IL-12. However, the addition of the gingipains in the presence of LPS resulted in partial restoration of the IFN-γ levels. In the destructive periodontitis lesion, release of gingipains from the outer membrane (OM) of P. gingivalis could lead to the downregulation of Th1 responses, while gingipain associated with LPS in the OM or in OM vesicles released from the organism could have net stimulatory effects.


2007 ◽  
Vol 75 (11) ◽  
pp. 5338-5345 ◽  
Author(s):  
Kee-Jong Hong ◽  
Jason R. Wickstrum ◽  
Hung-Wen Yeh ◽  
Michael J. Parmely

ABSTRACT The production of gamma interferon (IFN-γ) is a key step in the protective innate immune response to Francisella tularensis. Natural killer cells and T cells in the liver are important sources of this cytokine during primary F. tularensis infections, and interleukin-12 (IL-12) appears to be an essential coactivating cytokine for hepatic IFN-γ expression. The present study was undertaken to determine whether or not macrophages (Mφ) or dendritic cells (DC) provide coactivating signals for the liver IFN-γ response in vitro, whether IL-12 mediates these effects, and whether Toll-like receptor (TLR) signaling is essential to induce this costimulatory activity. Both bone marrow-derived Mφ and DC significantly augmented the IFN-γ response of F. tularensis-challenged liver lymphocytes in vitro. While both cell types produced IL-12p40 in response to F. tularensis challenge, only DC secreted large quantities of IL-12p70. DC from both IL-12p35-deficient and TLR2-deficient mice failed to produce IL-12p70 and did not costimulate liver lymphocytes for IFN-γ production in response to viable F. tularensis organisms. Conversely, liver lymphocytes from TLR2-deficient mice cocultured with wild-type accessory cells produced IFN-γ at levels comparable to those for wild-type hepatic lymphocytes. These findings indicate that TLR2 controls hepatic lymphocyte IFN-γ responses to F. tularensis by regulating DC IL-12 production. While Mφ also coinduced hepatic IFN-γ production in response to F. tularensis, they did so in a fashion less dependent on TLR2.


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