293 Cells high-titer concentration

Bums, J.C. (1993). Vesicular stomatitis virus G glycoprotein pseudotyped retroviral vectors concentration to very high titer and efficient gene transfer into mammalian and nonmammalian cells. Proc. Natl. Acad. Sci. U.S.A., 90, 8033-8037. 

Passive transfer of allo-antibodies present in donor plasma can also cause hemolytic transfusion reactions. Low-titer erythrocjde antibodies in donor blood are considered to be relatively harmless, especially when plasma-reduced or concentrated eiythrocytes are transfused in a recipient whose cells carry the relevant antigen. A comphcation of this type provoked by high-titer anti-E antibody has been described (90). Likewise, a hemolytic transfusion reaction occurred in a Kell-negative adult when anti-KeU contained in the plasma of a unit of whole blood reacted with Kell-positive cells transfused 4 weeks before (91). 

Stable protein Intracellular protein Non-toxic protein Known infection kinetics/cell growth rate Only low-titer/limited virus stocks available Bioreactor operation at high infection cell densities at or beyond 1-2x10 cells mL (fed-batch processes) Unstable protein Secreted protein Toxic/growth-retarding protein Unknown infection kinetics/cell growth rate Concentrated virus stocks available Bioreactor operation at medium to low cell densities (batch processes)... 

Recombinant adenoviruses have a number of properties that make them a useful alternative to recombinant retroviruses for human gene transfer. Recombinant adenoviruses are well characterized, relatively easy to manipulate, can be grown and concentrated to very high titers (up to lO infectious particles/ml), are stable particles, and can transduce a wide variety of cell types [37,38]. Furthermore, genes transferred by recombinant adenoviruses do not integrate, eliminating the risk of insertional mutagenesis of the... 

The following protocols are not optimized procedures for EIA, but they are suitable for screening, e.g., for antibody titers of sera or mAb cell culture supernatants. A high-performance EIA has to be evaluated with respect to selection of type of microtiter plates, coating concentration, coating conditions, analyte dilution, sample buffer, washing buffer, incubation times and temperatures, conjugate dilution, and substrate composition. 

The visualization method also worked with a 500-L perfusion reactor system for production of recombinant human coagulation factor VIII (hFVIII) in Chinese hamster ovary (CHO) cells [36,37]. Despite the diluted concentration of CHO cells and low titer of hFVIII in the medium, the nose could differentiate between the batch phase, medium replacement phase, and the high and low productivity phases during the five-week long cultivations (Fig. 10). The low concentration of hFVIII makes it credible to believe that there are other components associated with the product formation that the electronic nose responds to. 

Fed-Batch. Fed-batch processes start out as batch cultures after a few days of growth— when a crucial nutrient is depleted—a concentrated solution of nutrients is added to the media. Fed-batch cultures persist for one to two weeks and may produce high cell density and product titers, typically greater than 10 x 106 cells/mL and 1.5 g/L, respectively.43... 

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