Q.20 Which one of the following hosts is used in mammalian cell culture
for the production of glycosylated recombinant therapeutic proteins?
(A) Pichia pastoris
(B) Sf9 cells
(C) Escherichia coli
(D) Chinese hamster ovary cells
Chinese hamster ovary (CHO) cells serve as the primary host in mammalian cell culture for producing glycosylated recombinant therapeutic proteins, making option (D) the correct answer. This multiple-choice question tests knowledge of bioprocessing in biotechnology, particularly for biologics like monoclonal antibodies. Understanding why CHO cells outperform other hosts ensures accurate production of functional, human-like glycoproteins.
Correct Answer
Chinese hamster ovary cells (D) are the gold standard for mammalian cell culture in recombinant therapeutic protein production. These cells perform complex N-linked and O-linked glycosylation matching human patterns, essential for protein stability, efficacy, and immunogenicity avoidance in therapeutics. Over 70% of approved biologics use CHO cells due to their scalability and post-translational modification fidelity.
Option Breakdown
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(A) Pichia pastoris: This methylotrophic yeast excels in high-yield protein secretion but produces high-mannose glycosylation differing from mammals, often requiring engineering for humanization. Not suitable for standard mammalian cell culture.
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(B) Sf9 cells: Derived from fall armyworm ovaries, Sf9 insect cells support baculovirus expression systems (BEVS) with some glycosylation but yield simpler, paucimannose structures incompatible with full mammalian complexity.
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(C) Escherichia coli: Prokaryotic bacteria lack glycosylation machinery entirely, producing unglycosylated proteins prone to misfolding for therapeutics needing glycan functions.
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(D) Chinese hamster ovary cells: Mammalian origin enables authentic glycosylation, folding, and assembly in suspension cultures optimized for bioreactors.
Why Mammalian Hosts Excel
Glycosylation impacts half-life, receptor binding, and ADCC in drugs like etanercept or rituximab. CHO cells’ human-like Golgi processing ensures regulatory approval, unlike microbial or insect alternatives needing glycoengineering. For biotech exams like GATE BT, this highlights mammalian systems’ dominance in GMP manufacturing.
