All clinically-relevant blood components transmit prion disease following a single blood transfusion: a sheep model of vCJD

Variant CJD (vCJD) is an incurable, infectious human disease, likely arising from the consumption of BSE-contaminated meat products. Whilst the epidemic appears to be waning, there is much concern that vCJD infection may be perpetuated in humans by the transfusion of contaminated blood products. Since 2004, several cases of transfusion-associated vCJD transmission have been reported and linked to blood collected from pre-clinically affected donors. Using an animal model in which the disease manifested resembles that of humans affected with vCJD, we examined which blood components used in human medicine are likely to pose the greatest risk of transmitting vCJD via transfusion. We collected two full units of blood from BSE-infected donor animals during the pre-clinical phase of infection. Using methods employed by transfusion services we prepared red cell concentrates, plasma and platelets units (including leucoreduced equivalents). Following transfusion, we showed that all components contain sufficient levels of infectivity to cause disease following only a single transfusion and also that leucoreduction did not prevent disease transmission. These data suggest that all blood components are vectors for prion disease transmission, and highlight the importance of multiple control measures to minimise the risk of human to human transmission of vCJD by blood transfusion

Prion protein-specific antibodies that detect multiple TSE agents with high sensitivity

This paper describes the generation, characterisation and potential applications of a panel of novel anti-prion protein monoclonal antibodies (mAbs). The mAbs were generated by immunising PRNP null mice, using a variety of regimes, with a truncated form of recombinant ovine prion protein spanning residues 94–233. Epitopes of specific antibodies were mapped using solid-phase Pepscan analysis and clustered to four distinct regions within the PrP molecule. We have demonstrated the utility of these antibodies by use of Western blotting and immunohistochemistry in tissues from a range of different species affected by transmissible spongiform encephalopathy (TSE). In comparative tests against extensively-used and widely-published, commercially available antibodies, similar or improved results can be obtained using these new mAbs, specifically in terms of sensitivity of detection. Since many of these antibodies recognise native PrPC, they could also be applied to a broad range of immunoassays such as flow cytometry, DELFIA analysis or immunoprecipitation. We are using these reagents to increase our understanding of TSE pathogenesis and for use in potential diagnostic screening assays

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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Different profiles of PrP^d staining are evident when brain sections from TSE-infected sheep, goat, cow and deer were stained with ROS-IH9.

<p>Labelling for PrP^d in the brain (indicated by brown staining) from several ruminant species infected with different TSE agents using the antibody ROS-IH9 (0.0625 µg/ml). Experimental classical scrapie in sheep specifically the dorsal motor nucleus of the vagus nerve (DMNV, panel A); CH1641 scrapie in sheep (cerebellum, panel B); cattle BSE in sheep (DMNV, panel C); atypical scrapie in sheep (cerebellum, panel D); goat BSE in goat (DMNV, panel E); cattle BSE in red deer (cerebellum, panel F); classical scrapie in goat (hypothalamus, panel G); natural BSE in cattle (spinal tract of the trigeminal nerve, panel H). Scale bar = 200 µm.</p

ROS-BH1 stains PrP^d deposited after 87V infection in mice in a more sensitive manner compared to 6H4.

<p>Staining of PrP^Sc during 87V (scrapie) infection in the cortical hippocampus, the cortex and the CA2 region of the hippocampus in mice using ROS-BH1 (0.2 µg/ml, panels A, D and G), 6H4 (3.0 µg/ml, panels B, E and F) and the IgG1 isotype control antibody, TNP (0.2 µg/ml, panels C, F and I). Panels, G H and I are higher magnification images of the CA2 region. Neuroanatomical landmarks are identified as follows: Fi – fimbria; Th - thalamus; DG - dentate gyrus; CA2 - CA2 region of the hippocampus; CA1 - CA1 region of the hippocampus; Cx - cortex; V - ventricle and S - septum. Scale bars are indicated in µm. ROS-BH1 gave more sensitive detection of PrP^d in this assay compared to 6H4 whilst retaining an identical specificity and profile of staining to that of 6H4.</p

ROS-BC6 requires arginine (R) at codon 154 for binding to C1 PrP^C.

<p>Representative image of mature-length (FL) and C1 PrP^C (C1, deglycosylated forms) extracted from brain of seven sheep of either ARQ/AHQ (lane 1), ARQ/ARQ (lane 2) or AHQ/AHQ (lanes 3–7) PRNP genotypes. Membrane was probed with ROS-BC6 (0.3 µg/ml) simultaneously with anti-tubulin (T, 0.01 µg/ml). ROS-BC6 binds specifically to mature-length and C1 PrP in brain from ARQ/AHQ and ARQ/ARQ sheep but not from AHQ/AHQ sheep. Molecular weight markers are shown in kDa, exposure time was 10 minutes.</p