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Upstream processing for viral vaccines–General aspects
Published in Amine Kamen, Laura Cervera, Bioprocessing of Viral Vaccines, 2023
Lars Pelz, Sven Göbel, Karim Jaen, Udo Reichl, Yvonne Genzel
In order to determine the optimal harvest time point, the ratio of total virus titer to contaminants should be considered. For attenuated vaccines and viral vectors, a high infectious titer is necessary to achieve high potency, hence, an early harvest time point should be targeted. Certain viruses show a low stability, which is characterized by a steep decrease in infectivity over time. One possible countermeasure is a multiple harvest strategy, in which the virus is harvested and stored at lower temperature and new medium is added to the bioreactor. This strategy is often used for adherent cells and slowly propagating lytic viruses. Moreover, continuous harvesting with subsequent cooling to prevent degradation could also be applied (see chapter 6).
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Published in Raj Bawa, János Szebeni, Thomas J. Webster, Gerald F. Audette, Immune Aspects of Biopharmaceuticals and Nanomedicines, 2019
Raj Bawa, János Szebeni, Thomas J. Webster, Gerald F. Audette
Titers are defined as the maximal dilution where a sample gives a value above the screening cut point. Titers are often informative and can be linked to clinical impact of the ADA. Titering assays can be particularly informative when patients have pre-existing antibodies. Titering assays most often are performed using the same platform as the screening assay. Sera are tested in sequential dilutions. Alternatively, titer may be determined by extrapolating the dilution to the assay cut point using the linear portion of the dose response curve.
Hematopoietic Stem Cell Transplantation in Patients with Autoimmune Bullous Skin Disorders
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Patients have circulating IgG 1 and 4 autoantibodies that react to desmoglein 3 (Dsg-3).7-9 Most studies suggest a correlation between disease activity and antibody titer. Transplacental transfer of maternal pemphigus vulgaris antibodies may cause transient blisters in neonates. Purified pemphigus vulgaris IgG injected into neonatal mice causes intraepidermal acantholysis .
Effects of various pine needle extracts on Chinese hamster ovary cell growth and monoclonal antibody quality
Published in Preparative Biochemistry & Biotechnology, 2023
Dingyue Zhang, Jinshu Qiu, Qing-Tian Niu, Tingting Liu, Rulin Gu, Xiaoying Zhang, Shun Luo
An e2695 HPLC system (Waters, USA) with a TSKgel Protein A-5PW affinity chromatography column (TOSOH, Japan) was used to determine the mAb titer concentration in the supernatant. The mobile phase A was a 20 mmol/L phosphate buffer (NaH2PO4·H2O + Na2HPO4) at pH 7.0, and the mobile phase B was 20 mmol/L phosphate buffer at pH 2.5. The standard and samples were diluted with the mobile phase A before analysis. The chromatographic conditions were as follows: the sample chamber temperature at 10 °C, the column temperature at 25 °C, and the flow rate at 2 mL/min. The sample was separated by the pH gradient from 0% B to 100% B in 2 min. The eluted titer was detected at a wavelength of 280 nm and the titer concentration was calculated using the standard curve ranging from 0.2 to 4.0 mg/mL.