ISSN:
0006-3592
Keywords:
antibody integrity
;
human monoclonal antibodies
;
insect cells
;
mammalian cell culture
;
proteolytic activity
;
protein microheterogeneity
;
serum-free media
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
To investigate the effects of factors secreted by different cell lines on human monoclonal antibody (MAb) integrity, 600 mg of a human MAb, which specifically binds to human erythrocytes, were produced in a perfusion process. After purification by protein A affinity chromatography, the MAb was used for integrity testing in supernatants of several cell lines to investigate their potential to degrade the antibody in the extracellular environment. One insect cell line (IPLB-SF-21 AE) and four mammalian cell lines [CHO K1, BHK-21 (C13), C1271, P3-X63-Ag8.653], all of them commonly used for the production of recombinant proteins, and the human-human-mouse heterohybridoma cell line itself (H-CB-hahE), were adapted to serum-free culture media. For integrity testing all cell lines were cultivated in spinner flasks using serum-free media supplemented with 30 μg mL-1 of purified MAb. MAb integrity was assayed by SDS polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing, both followed by Western blotting, and an antigen binding assay. None of the mammalian cells showed any detectable effects on antibody stability and integrity during exponential growth, whereas isoelectric focusing of monoclonal antibody taken from IPLB-SF-21 AE culture supernatants revealed a new band indicating a partial modification of the MAb by secreted factors of these cells. This observation did not correlate with the total proteolytic activity, which was measured in all supernatants and found to be lowest in the insest cell cultures. For mammalian cell cultures, it could be concluded from these findings that shifts of the antibody microheterogeneity pattern, which can be found normally as a result of variations in different production parameters, are not caused by extracellular factors once the product has been secreted into the supernatant. In addition to their well-known advantages in posttranslational modifications (e.g., formation of complex type N-glycans), mammalian cells appear to be more suitable as expression systems for human monoclonal antibodies to be used in vivo when compared with baculovirus-infected insect cells. © 1995 John Wiley & Sons, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260450202
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