Role of IL-10 Deficiency in Pneumonia Induced by Corynebacterium kutscheri in Mice
ABSTRACT IL-10 is an important anti-inflammatory cytokine that can inhibit the production of many pro-inflammatory cytokines. Both human and animal studies have shown that pro-inflammatory cytokines play an important role in pneumonia and other inflammatory lung diseases. In the present study, IL-10 knockout (KO) and wild-type mice were infected with Corynebacterium kutscheri to determine whether the severity of pathogenesis and whether protective immunity could be altered in the absence of IL- 10. The survival rate was significantly lower in IL-10 KO mice than wild-type mice. The number of neutrophils in bronchoalveolar lavage fluid and blood were found to be higher in IL-10 KO mice than wild-type mice. IL-10 KO mice showed greater neutrophil infiltration, excessive inflammation, and weight-loss compared with wild-type mice. Furthermore, upregulation of IFN-gamma in bronchoalveolar lavage fluid, and upregulation of MIP-1alpha and IP-10 mRNA in the lungs of IL-10 KO mice compared with wild-type mice after C. kutscheri infection were observed. These results suggest that IL-10 plays an important role in the anti-inflammatory properties against C. kutscheri infection, and that lack of IL-10 leads to a more severe pulmonary inflammatory response. This increased susceptibility to C. kutscheri pneumonia is at least in part caused by IL-10 deficiency and severe recruitment of neutrophils.
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ABSTRACT: Chlamydia trachomatis is the leading cause of sexually transmitted infection worldwide, in which disease outcome is determined by the balance between pro- and anti-inflammatory host immune responses. Iron plays important roles in regulation and enhancement of various pro- and anti-inflammatory cytokines. Earlier studies have established essentiality of iron in C. trachomatis infection; however, there is lack of study wherein modulatory effect of iron regulated protein [FHC (ferritin heavy chain)] in regulation of anti-inflammatory cytokine IL (interleukin)-10 has been investigated. In this study, immunoblotting results showed the up-regulation of FHC in C. trachomatis-infected HeLa cells in comparison with mock (in vitro control). Further secretory IL-10 level was significantly increased (P<0.001) or decreased (P<0.001) in response to iron supplementation [FAC (ferric ammonium citrate)] and depletion [DFO (deferoxamine)], respectively. However, in C. trachomatis-infected HeLa cells, levels of IL-10 remain higher, irrespective of availability of iron in comparison with their respective control. These results showed that secretion of IL-10 and expressions of FHC have concordance. Further, to understand interdependence of IL-10 and iron homoeostasis (regulation), the levels of IL-10 were compared with iron-responsive GFP (green fluorescent protein) expression in HeLa-229 cells. The mean fluorescent intensities of GFP were in accordance with levels of IL-10 in C. trachomatis-infected cells. These results showed the association of secreted IL-10, FHC and iron homoeostasis in C. trachomatis-infected HeLa-229 cells. This study provides insight into host-Chlamydia interaction at the crossroad of iron metabolism and immune responses and may help in realizing the potential of iron homoeostasis modulators in treatment of chronic chlamydial infection.Cell Biology International 03/2011; 35(8):793-8. DOI:10.1042/CBI20100463
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ABSTRACT: Wild-type mice control murine cytomegalovirus (MCMV) brain infection, but identical infection is lethal to animals deficient in interleukin (IL)-10. Here, we report that MCMV-infected IL-10 knockout (KO) mice displayed a marked increase in neutrophil infiltration into the infected, IL-10-deficient brain when compared to wild-type animals. Enhanced microglial cell activation, determined by MHC class II up-regulation, overexpression of CXCL2, and elevated P-selectin mRNA levels were observed. In vivo blocking of CXCL2 attenuated neutrophil infiltration and significantly improved the outcome of infection. Collectively, these data indicate that the absence of IL-10 results in pathologic neutrophil infiltration into MCMV-infected brains.Journal of neuroimmunology 10/2010; 227(1-2):101-10. DOI:10.1016/j.jneuroim.2010.06.020
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ABSTRACT: Despite many reports documenting its epidemicity, little is known on the interaction of Acinetobacter baumannii with its host. To deepen our insight into this relationship, we studied persistence of and host response to different A. baumannii strains including representatives of the European (EU) clones I-III in a mouse pneumonia model. Neutropenic mice were inoculated intratracheally with five A. baumannii strains and an A. junii strain and at several days morbidity, mortality, bacterial counts, airway inflammation, and chemo- and cytokine production in lungs and blood were determined. A. baumannii RUH875 and RUH134 (EU clone I and II, respectively) and sporadic strain LUH8326 resulted in high morbidity/mortality, whereas A. baumannii LUH5875 (EU clone III, which is less widespread than clone I and II) caused less symptoms. A. baumannii type strain RUH3023(T) and A. junii LUH5851 did not cause disease. All strains, except A. baumannii RUH3023(T) and A. junii LUH5851, survived and multiplied in the lungs for several days. Morbidity and mortality were associated with the severity of lung pathology and a specific immune response characterized by low levels of anti-inflammatory (IL-10) and specific pro-inflammatory (IL-12p40 and IL-23) cytokines at the first day of infection. Altogether, a striking difference in behaviour among the A. baumannii strains was observed with the clone I and II strains being most virulent, whereas the A. baumannii type strain, which is frequently used in virulence studies appeared harmless.PLoS ONE 02/2012; 7(2):e30673. DOI:10.1371/journal.pone.0030673