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Rapid and Scalable Transient Transfection Technology
Poster: Rapid and Scalable Transient Transfection Technology for High Titer Protein Production in HEK, CHO and Other Cell Types.

Advancing Drug Discovery with the MaxCyte® STX™ Scalable Transient Transfection System
Poster: Advancing Drug Discovery with the MaxCyte® STX™ Scalable Transient Transfection System: Expression of Intracellular, Membrane-Bound and Secreted Proteins in Physiologically Relevant Cell Lines, Primary Cells and Stem Cells

Applications > Protein Production > Antibody Production

MaxCyte flow electroporation offers a viable alternative to stable cell lines for antibody production. Flow electroporation is a high efficiency method for transfection of cells commonly used in protein production including CHO cells. This enables production of antibodies in the quantities needed for most pre-clinical product development, in the same cellular background as stable cell lines used for antibody production during clinical studies. Thus the MaxCyte system allows for rapid production of antibodies during pre-clinical development phases followed by streamlined development of stable cell lines for specific antibodies of interest.


MaxCyte Electroporation for Antibody Production:

Antibody Expression in Transfected CHO Cells

CHO cells are commonly used to create stable cell lines for production of antibodies. Stable cell lines are labor-, time- and cost-intensive to create. To improve efficiency, MaxCyte flow electroporation of CHO cells can be used to rapidly express a variety of antibodies for screening and other applications. After appropriate antibody candidates are identified for migration to clinical trials, expression systems can subsequently be moved to creation of stable cell lines for only those antibodies identified to be of interest.

The data in Figure 1 summarize cell growth and antibody production following the transient transfection of CHO cells using the MaxCyte® STX™ Scalable Transfection System. Transfected cells exhibited a high level of viability and growth for the 3 day period post transfection. The effects of DNA toxicity at the highest 400μg/mL DNA concentration were observed on Day 3 post electroporation in which cell numbers were significantly lower than on Day 2. Despite the decrease in cell number, the 400µg/mL population of transfected cells still produced high titers of antibody for the 10 day observation period. The optimum DNA concentration was 300μg/mL, which lead to the highest levels of sustained cell viability and growth as well as the highest titers of antibody production throughout the 10 day study.

Extended Production of Antibodies from MaxCyte Transfected CHO Cells
Figure 1: Extended Production of Antibodies from MaxCyte Transfected CHO Cells. Cells were transfected with an equimolar mixture of heavy and light chain expression plasmids with a total DNA concentration of 200, 300, or 400μg/mL on day 0. Cell number and viability was measured on days 1, 2, & 3 following electroporation. Total IgG concentration in cell supernatant was measured using an ELISA on days 1, 3, 6, & 10.

Increased Protein Expression with Optimized Electroporation Parameters.

The MaxCyte STX instrument comes pre-loaded with specialized electroporation (EP) protocols for individual cell types. Standard MaxCyte protocols provide an optimal blend of loading efficiency and cell viability, which are ideally suited for generating cells for use in cell-based assays. MaxCyte has developed additional EP protocols for CHO and HEK cells that are designed specifically for high level protein expression. These protocols are used for transfecting cells both in small scale (5x105 to 4x107 cells in seconds) and large scale formats (up to 1x1010 cells in less than thirty minutes). After identifying a DNA concentration that yields optimal assay results at small scale, the EP process can be scaled up without impacting transfection efficiency or cell viability.

Figure 2 illustrates the relative effects of electroporation energy and DNA concentration on cell viability and protein expression in CHO cells. The increased electroporation energy of the CHO Protein Expression protocol resulted in the ability to load cells with greater quantities of pGFP DNA and in turn, lead to an increase in average GFP expression per cell when compared with the standard CHO protocol. Note that in the absence of DNA, electroporation had little impact on viability, even when using the higher energy protocol. The average cell viability was reduced due to DNA toxicity, and correlated directly with the amount of DNA loaded into the cell. Additionally, there was a further reduction in viability at higher DNA concentrations when using higher electroporation energy. The MaxCyte CHO and HEK protein expression protocols are optimized for higher level protein production rather than cell viability which is in contrast to the general electroporation protocols which balance transgene expression and cell viability levels.

ncreased Cell Loading with Protein Expression Protocols
Figure 2: Increased Cell Loading with Protein Expression Protocols. CHO cells were electroporated (EP) with 0, 200 or 400 μg/mL pGFP in small scale format (OC-100 processing assemblies) using either MaxCyte's standard CHO protocol or a CHO-specific protocol optimized for protein expression. Cells were seeded in shake flasks at approximately 1x106 cells/mL and assayed by FACS ~20 hrs post electroporation. Data are expressed for % cell viability, % GFP+ cells and the mean fluorescence intensity (MFI).