Consensus-based reporting standards for diagnostic test accuracy studies for paratuberculosis in ruminants

The Standards for Reporting of Diagnostic Accuracy (STARD) statement was developed to encourage complete and transparent reporting of key elements of test accuracy studies in human medicine. The statement was motivated by widespread evidence of bias in test accuracy studies and the finding that incomplete or absent reporting of items in the STARD checklist was associated with overly optimistic estimates of test performance characteristics. Although STARD principles apply broadly, specific guidelines do not exist to account for unique considerations in livestock studies such as herd tests, potential use of experimental challenge studies, a more diverse group of testing purposes and sampling designs, and the widespread lack of an ante-mortem reference standard with high sensitivity and specificity. The objective of the present study was to develop a modified version of STARD relevant to paratuberculosis (Johne’s disease) in ruminants. Examples and elaborations for each of the 25 items were developed by a panel of experts using a consensus-based approach to explain the items and underlying concepts. The new guidelines, termed STRADAS-paraTB (Standards for Reporting of Animal Diagnostic Accuracy Studies for paratuberculosis), should facilitate improved quality of reporting of the design, conduct and results of paratuberculosis test accuracy studies which were identified as “poor” in a review published in 2008 in Veterinary Microbiology

Non-H-2 genes alter the H-2 determined susceptibilities in immune complex nephritis

Non-H-2 genes alter the H-2 determined susceptibilities in immune complex nephritis. These experiments examined the effects of genes outside of the H-2 region on disease susceptibility and pathogenesis. Four strains of mice with the susceptible H-2 type, H-2d, but different non-H-2 genes were studied. B10.D2, Balb/c, NZB, and DBA/2J mice were injected with 4mg of apoferritin i.p. q.d. for 28 days. B10.D2 and Balb/c mice developed proliferative and crescentic glomerulonephritis. NZB mice developed proliferative and crescentic glomerulonephritis with wire loop lesions suggestive of lupus. DBA/2J mice developed only minimal mesangial proliferation without crescents or necrosis. Electron microscopy showed subepithelial and mesangial deposits in B10.D2, moderate subepithelial and mesangial deposits in Balb/c, and marked mesangial, subendothelial and subepithelial deposits in NZB. Immunofluorescence demonstrated the presence of IgG, IgM, C3 and apoferritin in these deposits. The DBA/2J mice had only minimal mesangial deposits by immunofluorescence and electron microscopy. These experiments demonstrate that non-H-2 genes alter the H-2d determined disease susceptibility seen in H-2 congenic mice. NZB genes can alter the disease so that lupus-like lesions develop and DBA/2J genes can substantially ameliorate the disease

Expression, purification and immunochemical characterization of recombinant bovine beta-lactoglobulin, a major cow milk allergen

International audienceThe immunological characteristics of a recombinant beta-lactoglobulin were studied using monoclonal antibodies, polyclonal antiserum and sera from allergic patients. Recombinant beta-lactoglobulin (rBLG) was expressed in Escherichia coli strain DH5alpha and purified as described previously [Cho et al. (1994) J. Biol. Chem. 269, 11 102-11 107]. The method has been modified by adding an immunoaffinity purification step. A quantity of 5-10mg of purified rBLG per liter of medium culture can be produced. rBLG shared the same molecular weight as the natural BLG (nBLG) and also possessed at least one intrachain disulfide bridge. In HPLC, rBLG appeared as a single peak, and the purity was estimated to be greater than 95%. All the monoclonal antibodies (mAbs) used in this study recognized different epitopes of the BLG and presented compatible binding. No differences could be detected between rBLG and nBLG when tested in a Western blot with rabbit polyclonal antiserum or with three mAbs that bound preferentially the reduced and S-carboxymethylated form of BLG. In a competitive enzyme immunoassay (EIA) using either a rabbit polyclonal antiserum or four mAbs that recognized conformational epitopes, we could not distinguish between rBLG or nBLG. In direct ELISA using nBLG or rBLG as the immobilized allergen, we measured a similar concentration of specific anti-BLG IgE in five sera from allergic patients. The results of this study indicate that we have obtained a rBLG with biochemical and immunological properties very similar to nBLG