TT virus infection: role of interferons, interleukin-28 and 29, cytokines and antiviral proteins

Torque teno virus in liver diseases: On the way towards unity of view

The review presents the data accumulated for more than 20 years of research of torque teno virus (TTV). Its molecular genetic structure, immunobiology, epidemiology, diagnostic methods, possible replication sites, and pathogenicity factors are described. TTV is a virus that is frequently detectable in patients with different viral hepatitides, in cases of hepatitis without an obvious viral agent, as well as in a healthy population. There is evidence suggesting that biochemical and histological changes occur in liver tissue and bile duct epithelium in TTV monoinfection. There are sufficient histological signs of liver damage, which confirm that the virus can undergo a replicative cycle in hepatocytes. Along with this, cytological hybridization in TTV-infected cells has shown no substantial cytopathic (cell-damaging) effects that are characteristic of pathogenic hepatotropic viruses. Studying TTV has led to the evolution of views on its role in the development of human pathology. The first ideas about the hepatotropism of the virus were gradually reformed as new data became available on the prevalence of the virus and its co-infection with other viruses, including the viruses of the known types of hepatitides. The high prevalence of TTV in the human population indicates its persistence in the body as a virome and a non-pathogenic virus. It has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body’s immune status. The available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis viruses. Fortunately, the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic properties. The ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.

Success of measles virotherapy in ATL depends on type I interferon secretion and responsiveness

Adult T cell leukemia/lymphoma (ATL) is a highly aggressive CD4+/CD25+ T-cell malignancy caused by human T cell lymphotropic virus type 1 (HTLV-1). Previous studies in the MET-1 cell/NOD/SCID mouse model of ATL demonstrated that MET-1 cells are very susceptible to measles virus (MV) oncolytic therapy. To further evaluate the potential of MV therapy in ATL, the susceptibility of several HTLV-1 transformed CD4+ T cell lines (MT-1, MT-2, MT-4 and C8166-45) as well as HTLV-1 negative CD4+ T cell lines (Jurkat and CCRF-CEM) to infection with MV was tested in vitro. All cell lines were permissive to MV infection and subsequent cell death, except MT-1 and CCRF-CEM cells which were susceptible and permissive to MV infection, but resistant to cell death. The resistance to MV-mediated cell death was associated with IFNβ produced by MT-1 and CCRF-CEM cells. Inhibition of IFNβ rendered MT-1 and CCRF-CEM cells susceptible to MV-mediated cell death. Cells susceptible to MV-induced cell death did not produce nor were responsive to IFNβ. Upon infection with Newcastle Disease Virus (NDV), MT-1 and CCRF-CEM but not the susceptible cell lines up-regulated pSTAT-2. In vivo, treatment of tumors induced by MT-1 cell lines which produce IFNβ demonstrated only small increases in mean survival time, while only two treatments prolonged mean survival time in mice with MET-1 tumors deficient in type I interferon production. These results indicate that type I interferon production is closely linked with the inability of tumor cells to respond to type I interferon. Screening of tumor cells for type I interferon could be a useful strategy to select candidate patients for MV virotherapy.

Substance P: An Inflammatory Peptide

Substance P (SP) is involved in neurogenic inflammation and in the pathogenesis of several inflammatory diseases, demonstrating that there is a narrow interrelationship between the nervous system and immunity. Macrophage functions are altered in stress, therefore, since SP is a macrophage activator, its biological effect has been intimately linked to stress. In fact, SP enhances LPS-induced macrophage TNFα production from stressed animals and stimulates the production of IL-8 CXC chemokine response in a mast cell line in vitro. The stress-induced cytokines from macrophage also alter and contribute to inflammation. Understanding the pathophysiology of inflammation and the role of the chemical mediator SP may improve inflammation management.

Anti-chemokine therapy for inflammatory diseases

Chemokines are inflammatory proteins acting via G-protein coupled chemokine receptors that trigger different signaling pathways. Monocyte chemoattractant protein-1 (CCL2/MCP-1) and regulated on activation, normal T expressed and secreted (CCL5/RANTES) are the two major members of the CC chemokine beta subfamily. The roles of RANTES and MCP-1 are emerging in regulating the recruitment of inflammatory cells into tissue during inflammation. The inhibition of MCP-1 and RANTES with corresponding antibodies or other inhibitors may provide benefits in different clinical scenarios including cancer, inflammation, CNS disorders, parasitic disease, autoimmune and heart diseases. RANTES and MCP-1 may represent targets for diagnostic procedures and therapeutic intervention, and may be useful as a prognostic factor in the above diseases.

The Effect of Porcine Orexin a on C-Peptide Plasma Concentrations in Pigs

The hypothalamus and the neuropeptides that are produced and act within its neuronal circuits constitute an area of extensive laboratory research. In 1998, the neuropeptide, Orexin A, was discovered and isolated from the hypothalamus of the rat. An i.c.v. injection of Orexin A into the lateral ventricle of the rat's brain causes an increase in the consumption of food, and, apart from appetite, it also seems to be regulating many other normal functions of the organism, whose regulatory and metabolic mechanisms remain unknown to date. The neuropeptide is produced by a small cluster located in and round the lateral hypothalamic area. It has been known for decades that this area is involved in the regulation of feeding and energy homeostasis in mammals. The intravenous, subcutaneous, or i.c.v. injection of Orexin A causes changes in insulin and glucagon concentrations. The same effect is also seen under in vitro experimental conditions. In this study, we investigated the potential effects of i.c.v. administration of porcine Orexin A on c-peptide concentrations in the peripheral blood of pigs, and tested whether these changes are associated with the potential effect of the neuropeptide on the function of the pancreas.