Here, VP40 from the Ravn strain (RAVV VP40)-from a distinct Marburg virus
Wnt inhibitor clade-is demonstrated to also inhibit IFN signaling in human cells. However, neither MARV nor RAVV VP40 effectively inhibited IFN-signaling in mouse cells, as assessed by assays of the antiviral effects of IFN-alpha/beta and the IFN-alpha/beta-induced phosphorylation of Jak1, STAT1, and STAT2. In contrast, the VP40 from a mouse-adapted RAVV (maRAVV) did inhibit IFN signaling. Effective Jak1 inhibition correlated with the species from which the cells were derived and did not depend upon whether Jak1 was of human or mouse origin. Of the seven amino acid changes that accumulated in VP40 during mouse adaptation, two (V57A and T165A) are sufficient to allow efficient IFN signaling antagonism by RAVV VP40 in mouse cells. The same two changes also confer efficient IFN GSK621 manufacturer antagonist function upon MARV VP40 in mouse cells. The mouse-adaptive changes did not affect the budding of RAVV VP40 in mouse cells, suggesting that this second major function of VP40 did not undergo adaptation. These data identify an apparent determinant of RAVV host range
and virulence and define specific genetic determinants of this function.”
“Introduction: The ligand to antibody ratio is an important characteristic of a chelate/antibody conjugate. It has been widely reported that if the ratio is too high, there will be detrimental effects on immunoreactivity and biodistribution; conversely, if the ratio is too low, the radionuclide may not bind efficiently, and the stability and the specific activity will be reduced. There are little published data on the accuracy or precision of the Co-57 assay. The UK Clinical Trials Regulations state that “”systems with procedures that assure the quality
of every aspect of the trial should be implemented”". The aims of this study were to assess the reliability and accuracy of the Co-57 binding assay and validate it against defined criteria.
Method: Org 27569 Thirty-two serial assays were assessed for reliability. Two batches of conjugated antibody were also analysed by matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) mass spectrometry (MS) to allow the comparison of the functional test with a physical method.
Results: Reliability: The coefficient of variation was 0.13. Accuracy: There was 9% variation between the Co-57 binding assay and MALDI-TOF MS results.
Conclusion: A detailed method for the Co-57 ligand to antibody test is described that allows a discrete value to be obtained. The assay was validated as fit for purpose against larger values of coefficient of variation <0.20, accuracy +/- 10%, over a permissive range of 0.5-3.0 ligand to antibody ratio. (C) 2011 Elsevier Inc. All rights reserved.