Julia Tait Lathrop

Reduction in infectivity of endogenous transmissible spongiform encephalopathies present in blood by adsorption to selective affinity resins

BACKGROUND Transmissible spongiform encephalopathies (TSE) can be contracted through blood transfusion. Selective adsorption of the causative agent from donated blood might be one of the best ways of managing this risk. In our study, affinity resin L13, which reduces brain-derived infectivity spiked into human red blood cell concentrate by around 4 log(10)ID(50), and its equivalent, L13A, produced on a manufacturing scale, were assessed for their ability to remove TSE infectivity endogenously present in blood. METHODS 500 mL of scrapie-infected hamster whole blood was leucoreduced at full scale before passage through the affinity resins. Infectivity of whole blood, leucoreduced whole blood (challenge), and the recovered blood from each flow-through was measured by limiting dilution titration. FINDINGS Leucoreduction removed 72% of input infectivity. 15 of 99 animals were infected by the challenge, whereas none of the 96 or 100 animals inoculated with the final flow-throughs from either resin developed the disease after 540 days. The limit of detection of the bioassay was 0.2 infectious doses per mL. The overall reduction of the challenge infectivity was more than 1.22 log10ID. The results showed removal of endogenous TSE infectivity from leucoreduced whole blood by affinity ligands. The same resins adsorb normal and abnormal prion protein from human infections with variant, sporadic, and familial Creutzfeldt-Jakob disease, in the presence of blood components. INTERPRETATION TSE affinity ligands, when incorporated into appropriate devices, can be used to mitigate the risks from TSE-infected blood, blood products, and other materials exposed to TSE infectivity.

Reduction of transmissible spongiform encephalopathy infectivity from human red blood cells with prion protein affinity ligands

BACKGROUND:  There is a demonstrated risk of infection by transmissible spongiform encephalopathies (TSEs) through transfusion from asymptomatic donors. Currently, blood‐borne TSE infectivity cannot be detected with a diagnostic test, nor is it likely to be amenable to inactivation; however, its depletion with specific adsorp‐tive ligand resins is possible.

Rarity gives a charm: evaluation of trace proteins in plasma and serum

Since plasma potentially contacts every cell as it circulates through the body, it may carry clues both to diagnosis and treatment of disease. It is commonly expected that the growing ability to detect and characterize trace proteins will result in discovery of novel therapeutics and biomarkers; however, the familiar, super-abundant plasma proteins remain a fundamental stumbling block. Furthermore, robust validation of proteomic data is a sometimes overlooked but always necessary component for the eventual development of clinical reagents. This review surveys some of the uses of typical and atypical low-abundance proteins, current analytical methods, existing impediments to discovery, and some innovations that are overcoming the challenges to evaluation of trace proteins in plasma and serum.

The Bead blot: a method for selecting small molecule ligands for protein capture and purification.

We present a new method for selecting peptide ligands that are useful for protein purification, protein targeting and exploring protein–ligand interactions, and which requires no prior protein purification or derivatization. In the Bead blot, a complex mixture containing the target protein, for example, plasma, is incubated with a combinatorial library of peptide ligands synthesized on beads. The proteins are fractionated and purified on their respective ligands and the beads with their bound proteins are immobilized in a gel. The proteins are eluted from the ligands by capillary action and captured on a membrane so that their position on the membrane corresponds to the position of the beads in the gel. The protein is detected on the membrane, generating spots on an autoradiography film, the spots on the film are aligned with the beads in the gel, and the beads that bound the protein are recovered. The ligand on the bead(s) can be sequenced and synthesized at large scale for protein purification. The Bead blot can be completed in several hours with overnight pause steps if desired. On average, 5 prospective ligands are selected per 50,000 beads screened using this method. Unlike other ligand identification methods, the target protein does not have to be purified or labeled, and the Bead blot allows ligands for multiple proteins to be selected in a single experiment.

P30 Removal of the Endogenous TSE Infectivity From Blood Using PRDT TSE Affinity Resin And Integration Of The Resin Into The Macopharma P‐CAPT™ Filter

Background  To date, there have been three transfusion transmitted cases of vCJD among 19 recipients that are known to have received blood from persons that later died of vCJD and lived long enough themselves to have developed detectable disease. This is a transmission rate of ∼15%. A survey of surgically removed tissues concluded that the number of incubating cases of vCJD in the UK was at least 4000. Seven percent of this group would on average be blood donors.