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Natural Immune Response (natural + immune_response)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Possible Role of Natural Immune Response against Altered Fibroblasts in the Development of Post-Operative Adhesions

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2006
Zeynep Alpay
Problem Post-operative adhesion tissue fibroblasts (ATF) differ from normal peritoneal fibroblasts (NPF). Natural immune response participates in the elimination of altered cells. In this study, we investigated NPF and ATF expression patterns of immune response-related markers, and lymphokine-activated killer (LAK) cell-mediated fibroblast elimination in vitro. Method of study Primary cell cultures of both NPF and ATF obtained from the same four patients were used in the experiments. The expression of CD54, CD40 and CD120b, and allogeneic LAK cell-mediated ATF and NPF elimination were studied by flow cytometry. Results Average expression of CD54 in ATF was greater by 12.3-fold compared with NPF (P = 0.021), with ratios of 2.4 and 1.9-fold for CD40 (P < 0.001) and CD120b (P = 0.013), respectively. Average LAK cell-mediated fibroblast killing was 1.8 ± 0.8-fold greater in ATF over NPF (P = 0.008). Furthermore, LAK cell-mediated fibroblast elimination correlated significantly with the increased CD40, CD54 and CD120b expression (R > 0.956; P < 0.05 for each). Conclusions These results demonstrate that ATF are more susceptible to lymphocyte-mediated elimination than NPF and the development of adhesions despite this could be explained by either impaired or overwhelmed autologous natural immune response against reactive fibroblasts. [source]

The large form of ADAR 1 is responsible for enhanced hepatitis delta virus RNA editing in interferon- , -stimulated host cells

JOURNAL OF VIRAL HEPATITIS, Issue 3 2006
D. Hartwig
Summary., Hepatitis delta virus (HDV) RNA editing controls the formation of hepatitis-delta-antigen-S and -L and therefore indirectly regulates HDV replication. Editing is thought to be catalysed by the adenosine deaminase acting on RNA1 (ADAR1) of which two different forms exist, interferon (IFN)- , -inducible ADAR1-L and constitutively expressed ADAR1-S. ADAR1-L is hypothesized to be a part of the innate cellular immune system, responsible for deaminating adenosines in viral dsRNAs. We examined the influence of both forms on HDV RNA editing in IFN- , -stimulated and unstimulated hepatoma cells. For gene silencing, an antisense oligodeoxyribonucleotide against a common sequence of both forms of ADAR1 and another one specific for ADAR1-L alone were used. IFN- , treatment of host cells led to approximately twofold increase of RNA editing compared with unstimulated controls. If ADAR1-L expression was inhibited, this substantial increase in editing could no longer be observed. In unstimulated cells, ADAR1-L suppression had only minor effects on editing. Inhibition of both forms of ADAR1 simultaneously led to a substantial decrease of edited RNA independently of IFN- , -stimulation. In conclusion, the two forms of ADAR1 are responsible almost alone for HDV editing. In unstimulated cells, ADAR1-S is the main editing activity. The increase of edited RNA under IFN- , -stimulation is because of induction of ADAR1-L, showing for the first time that this IFN-inducible protein is involved in the base modification of replicating HDV RNA. Thus, induction of ADAR1-L may at least partially cause the antiviral effect of IFN- , in natural immune response to HDV as well as in case of therapeutic administration of IFN. [source]