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Uninfected Animals (uninfected + animals)
Selected AbstractsLack of response to exogenous interferon-, in the liver of chimpanzees chronically infected with hepatitis C virus,,HEPATOLOGY, Issue 4 2007Robert E. Lanford The mechanism of the interferon-alpha (IFN,),induced antiviral response is not completely understood. We recently examined the transcriptional response to IFN, in uninfected chimpanzees. The transcriptional response to IFN, in the liver and peripheral blood mononuclear cells (PBMCs) was rapidly induced but was also rapidly down-regulated, with most interferon-alpha,stimulated genes (ISGs) returning to the baseline within 24 hours. We have extended these observations to include chimpanzees chronically infected with hepatitis C virus (HCV). Remarkably, using total genome microarray analysis, we observed almost no induction of ISG transcripts in the livers of chronically infected animals following IFN, dosing, whereas the response in PBMCs was similar to that in uninfected animals. In agreement with this finding, no decrease in the viral load occurred with up to 12 weeks of pegylated IFN, therapy. The block in the response to exogenous IFN, appeared to be HCV-specific because the response in a hepatitis B virus,infected animal was similar to that of uninfected animals. The lack of a response to exogenous IFN, may be due to an already maximally induced ISG response because chronically HCV-infected chimpanzees already have a highly up-regulated hepatic ISG response. Alternatively, negative regulation may block the response to exogenous IFN,, yet it does not prevent the continued response to endogenous ISG stimuli. The IFN, response in chronically HCV-infected chimpanzees may be mechanistically similar to the null response in the human population. Conclusion: In chimpanzees infected with HCV, the highly elevated hepatic ISG expression may prevent the further induction of ISGs and antiviral efficacy following an IFN, treatment. (HEPATOLOGY 2007.) [source] The effects of cowpox virus on survival in natural rodent populations: increases and decreasesJOURNAL OF ANIMAL ECOLOGY, Issue 4 2002Sandra Telfer Summary 1The effect of cowpox virus on survival in two rodent hosts was investigated using nearly 4 years of longitudinal data from two sites. 2We investigated whether an individual's probability of infection influenced the probability of surviving the next month. We also investigated the effect at the population level, examining whether, in addition to seasonal effects, changes in cowpox prevalence explained further temporal variation in survival rates. 3In bank voles, but not wood mice, individuals with high probabilities of infection survived better than uninfected animals. 4At the level of the population, the effect of infection on survival varied through the year in both species. Survival rates in late summer increased with cowpox prevalence, whilst survival rates in winter decreased with cowpox prevalence. 5We discuss why parasites such as cowpox virus may increase or decrease host survival and why the effect may depend on the time of year. [source] Enterochromaffin cell hyperplasia and decreased serotonin transporter in a mouse model of postinfectious bowel dysfunctionNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2005J. Wheatcroft Abstract, Patients with postinfective irritable bowel syndrome and Trichinella spiralis -infected mice share many features including visceral hypersensitivity and disordered motility. We assessed enterochromaffin (EC) numbers and serotonin transporter (SERT) using National Institute of Health (NIH) female mice studied for up to 56 days post- T. spiralis infection. The effects of steroid treatment and the T-cell dependence of the observed responses were assessed by infection of hydrocortisone-treated or T-cell receptor knock out [TCR (,×,) KO] animals. Enterochromaffin cell density in uninfected animals increased from duodenum 10.0 cells mm,2 (5.9,41.0) to colon 61.8. (46.3,162) cells mm,2P < 0.0001. Infection increased duodenal and jejunal counts which rose to 37.3 (22,57.7) cells mm,2 and 50.6 (7,110.8) cells mm,2, respectively, at day 14. Infection significantly reduced jejunal SERT expression, with luminance values falling from 61.0 (45.1,98.3) to a nadir of 11.6 (0,36.0) units at day 9, P < 0.001. Specific deficiencies in all T cells reduced EC hyperplasia and abrogated infection-induced mastocytosis. Thus infection induced inflammation increases EC numbers, as has been reported in PI-IBS, and reduces SERT. This may increase mucosal 5HT availability and contribute to the clinical presentation of PI-IBS. [source] Differences in immune parameters are associated with resistance to Haemonchus contortus in Caribbean hair sheepPARASITE IMMUNOLOGY, Issue 7 2010K. M. MacKINNON Summary Caribbean hair sheep are more resistant to gastrointestinal nematodes than conventional wool breeds, but mechanisms that confer resistance are not fully understood. This study compared immune effector cell populations and antibody concentrations in 12 hair and 12 wool lambs infected with the abomasal parasite Haemonchus contortus and sacrificed at 3 or 27 days post-infection (p.i.) and 14 uninfected animals of each breed. Faecal egg counts were over 2·5-fold higher (P = 0·12) and packed cell volumes approximately 8% lower (P < 0·10) in infected wool lambs. Abomasal lymph nodes were heavier in infected animals (P < 0·05) and infected hair sheep had larger lymph nodes than infected wool sheep (P < 0·05). Tissue eosinophil concentrations were likewise larger (P = 0·07) in hair compared with wool sheep at 3 days p.i. Circulating levels of IgE and IgA in uninfected lambs were higher in hair sheep (P < 0·05) and during infection, hair sheep had higher serum IgA than wool sheep at 3, 5, and 21 days p.i. (P < 0·05). Serum IgE in infected lambs did not differ between breeds, but concentrations of IgE in lymph nodes were higher (P < 0·01) at 27 days p.i. in infected hair sheep. [source] Proteomic identification of peroxiredoxin 6 for host defence against Opisthorchis viverrini infectionPARASITE IMMUNOLOGY, Issue 5 2010J. KHOONTAWAD Summary Opisthorchis viverrini infection causes opisthorchiasis and is a risk factor for cholangiocarcinoma via chronic inflammation. To investigate the mechanism of O. viverrini -induced liver disease, we applied a proteomic approach to examine alterations in hepatic protein levels in O. viverrini -infected hamsters. Two-dimensional gel electrophoresis (2DE) revealed that O. viverrini infection induced upregulation (1·5- to 4·3-fold) of 25 proteins and downregulation (1·5 to 2·5-fold) of 24 proteins compared with uninfected animals. Expression of proteins related to stress response, DNA replication and repair, and cell structure was significantly increased, whereas that of proteins associated with normal liver function, such as metabolism, blood volume maintenance and fatty acid cycle was decreased. Among the upregulated proteins, a 2·7-fold increase in peroxiredoxin 6 (Prdx6), an antioxidant protein, was confirmed by 2DE and immunoblot analysis, Western blot and quantitative PCR. Immunohistochemical analysis showed that Prdx6 expression was observed mainly in the cytoplasm of inflammatory cells. These results suggest that Prdx6 is important for host defence against O. viverrini infection. This study provides basic information for Prdx6 as a potential biomarker and therapeutic target for opisthorchiasis. [source] Differential regulation of nitric oxide synthase isoforms in experimental acute Chagasic cardiomyopathyCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2000B. Chandrasekar We have previously demonstrated induction and high level expression of IL-1,, IL-6 and tumour necrosis factor-alpha in the myocardium during the acute stage of experimental Trypanosoma cruzi infection (Chagas' disease). The myocardial depressive effects of these cytokines are mediated in part by the induction of nitric oxide synthase (NOS), production of nitric oxide (NO) and formation of peroxynitrite. In this study we investigated the expression, activity and localization of NOS isoforms, and the levels of NO, malondialdehyde (a measure of oxidative stress), and peroxynitrite in rats at 1·5, 5, 10 and 15 days after infection with T. cruzi trypomastigotes. The myocardial inflammatory infiltrate and number of amastigote nests increased over the course of infection. A significant increase in tissue nitrate + nitrite levels, NOS2 mRNA, and NOS2 enzyme activity was observed at all time points in the infected compared with uninfected animals. The enzyme activity of constitutive NOS, tissue malondialdehyde levels, and NOS3 mRNA levels was only transiently increased after infection. The protein levels of the NOS isoforms paralleled their mRNA expression. While no positive nitrotyrosine immunoreactivity was detected in control myocardium, its levels increased in infected animals over time. Thus, by 1·5 days post-infection, when no parasite or immune cell infiltration could be detected, the myocardium expressed high levels of NOS and NO metabolites. Nevertheless, the early production of NO in the myocardium was not sufficient to clear the parasites. [source] | ||||||||||