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- Kalyoncu, Sibel, et al.
(författare)
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Process development for an effective COVID-19 vaccine candidate harboring recombinant SARS-CoV-2 delta plus receptor binding domain produced by Pichia pastoris
- 2023
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Recombinant protein-based SARS-CoV-2 vaccines are needed to fill the vaccine equity gap. Because protein-subunit based vaccines are easier and cheaper to produce and do not require special storage/transportation conditions, they are suitable for low-/middle-income countries. Here, we report our vaccine development studies with the receptor binding domain of the SARS-CoV-2 Delta Plus strain (RBD-DP) which caused increased hospitalizations compared to other variants. First, we expressed RBD-DP in the Pichia pastoris yeast system and upscaled it to a 5-L fermenter for production. After three-step purification, we obtained RBD-DP with > 95% purity from a protein yield of > 1 g/L of supernatant. Several biophysical and biochemical characterizations were performed to confirm its identity, stability, and functionality. Then, it was formulated in different contents with Alum and CpG for mice immunization. After three doses of immunization, IgG titers from sera reached to > 106 and most importantly it showed high T-cell responses which are required for an effective vaccine to prevent severe COVID-19 disease. A live neutralization test was performed with both the Wuhan strain (B.1.1.7) and Delta strain (B.1.617.2) and it showed high neutralization antibody content for both strains. A challenge study with SARS-CoV-2 infected K18-hACE2 transgenic mice showed good immunoprotective activity with no viruses in the lungs and no lung inflammation for all immunized mice.
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- Hansson, Oskar, et al.
(författare)
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Pre-analytical protocol for measuring Alzheimer's disease biomarkers in fresh CSF
- 2020
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Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: We aimed to establish a standardized, routine-use pre-analytical protocol for measuring Alzheimer's disease (AD) biomarkers in cerebrospinal fluid (CSF). Methods: The effect of pre-analytical factors (sample collection/handling/storage/transportation) on biomarker levels was assessed using freshly collected CSF. Tube type/sterilization was assessed using previously frozen samples. A low-bind false-bottom tube (FBT, Sarstedt) was used for all experiments, except tube types/sterilization experiments. Biomarkers were measured using Elecsys CSF assays. Results: Amyloid beta (Aβ)1-42 levels varied by tube type, using a low-bind FBT reduced variation. Aβ1-42 levels were higher with no mixing versus roller/inversion mixing. Aβ1-42 levels were lower with horizontal versus upright transportation; this was resolved by maximal tube filling and storage at 2°C to 8°C. Aβ1-40 levels were less strongly affected. Phospho-tau and total-tau levels were largely unaffected. Discussion: We propose an easy-to-use, standardized, routine-use pre-analytical protocol, using low-bind FBTs, for measuring AD CSF biomarkers in clinical practice.
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