rDNA & Hybridoma in Drug Discovery: biotechnology-derived pharmaceuticals MCQs With Answer

Introduction: rDNA & Hybridoma in Drug Discovery: biotechnology-derived pharmaceuticals MCQs With Answer is a concise collection tailored for M.Pharm students preparing for advanced courses and examinations. This set focuses on recombinant DNA technologies and hybridoma methods that underpin modern biologics development—covering cloning strategies, expression systems, antibody production, humanization, downstream processing, and regulatory considerations. The questions probe conceptual understanding and practical nuances such as vector selection, promoter choice, glycosylation effects, monoclonal antibody mechanisms, and stability of hybridoma lines. Use these MCQs to deepen critical thinking, reinforce lab-to-clinic translation, and prepare for research or industry roles involving biotechnology-derived therapeutics.

Q1. Which promoter is commonly used for high-level inducible expression of recombinant proteins in E. coli and is driven by T7 RNA polymerase?

• lac promoter
• T7 promoter
• CMV promoter
• gal1 promoter

Correct Answer: T7 promoter

Q2. In recombinant protein production, what is the primary advantage of using a eukaryotic mammalian expression system (e.g., CHO cells) over E. coli?

• Lower production cost per gram
• Faster doubling time for culture expansion
• Capability for complex post-translational modifications such as human-like glycosylation
• Easier plasmid maintenance without selection markers

Correct Answer: Capability for complex post-translational modifications such as human-like glycosylation

Q3. Which selection system is typically used to isolate hybridoma cells that have successfully fused with myeloma cells producing HPRT-negative phenotype?

• Ampicillin selection
• HAT medium
• Kanamycin selection
• G418 selection

Correct Answer: HAT medium

Q4. In hybridoma production, polyethylene glycol (PEG) is used primarily for what purpose?

• To select fused cells in HAT medium
• To induce antibody secretion from myeloma cells
• To fuse B lymphocytes with myeloma cells
• To transfect hybridomas with expression plasmids

Correct Answer: To fuse B lymphocytes with myeloma cells

Q5. When expressing a recombinant secreted protein in mammalian cells, which element is essential to direct the protein into the secretory pathway?

• Antibiotic resistance gene
• N-terminal signal peptide (signal sequence)
• Internal ribosome entry site (IRES)
• Polyadenylation signal only

Correct Answer: N-terminal signal peptide (signal sequence)

Q6. Which method is most appropriate for early screening of hybridoma supernatants for antigen-specific antibody production?

• ELISA
• SDS-PAGE under reducing conditions
• Mass spectrometry glycan profiling
• Size-exclusion chromatography

Correct Answer: ELISA

Q7. What is the main reason inclusion bodies form during recombinant protein expression in E. coli?

• Excessive glycosylation
• Rapid folding into native conformation
• High-level expression leading to misfolding and aggregation
• Efficient secretion into periplasm

Correct Answer: High-level expression leading to misfolding and aggregation

Q8. Which purification method is the gold standard for initial capture of IgG-class monoclonal antibodies from culture supernatant?

• Ion exchange chromatography
• Protein A affinity chromatography
• Hydrophobic interaction chromatography
• Size-exclusion chromatography

Correct Answer: Protein A affinity chromatography

Q9. CDR grafting is a technique used in antibody engineering to achieve which outcome?

• Convert an antibody to a single-chain Fv format
• Reduce antibody affinity to antigen
• Humanize a non-human antibody by transferring complementarity-determining regions into a human framework
• Create bispecific antibodies by linking two heavy chains

Correct Answer: Humanize a non-human antibody by transferring complementarity-determining regions into a human framework

Q10. Which glycan feature on the Fc region of an IgG antibody most directly influences antibody-dependent cellular cytotoxicity (ADCC)?

• Presence of core fucose
• Terminal sialylation only
• Mannose trimming in the light chain
• Phosphorylation of N-linked glycans

Correct Answer: Presence of core fucose

Q11. Which vector feature is most important to ensure strong transcription in mammalian expression vectors?

• Origin of replication for E. coli
• Antibiotic resistance for bacterial selection
• Strong mammalian promoter such as CMV
• Multiple cloning site (MCS) only

Correct Answer: Strong mammalian promoter such as CMV

Q12. In rDNA-based protein engineering, site-directed mutagenesis is used primarily to:

• Integrate plasmids into the host genome
• Create precise amino acid substitutions to alter activity, stability, or pharmacokinetics
• Increase plasmid copy number non-specifically
• Remove all post-translational modifications

Correct Answer: Create precise amino acid substitutions to alter activity, stability, or pharmacokinetics

Q13. What is a critical regulatory concern specific to biologics derived from rDNA/hybridoma processes compared to small molecules?

• Bulk chemical impurity profiling
• Batch-to-batch consistency with respect to glycosylation, potency and impurity profile
• Patentability of synthetic routes
• Volatility limits in formulation

Correct Answer: Batch-to-batch consistency with respect to glycosylation, potency and impurity profile

Q14. Which of the following is a common myeloma fusion partner cell line used to make hybridomas?

• HEK293
• CHO-K1
• SP2/0
• Pichia pastoris

Correct Answer: SP2/0

Q15. A major cause of immunogenicity in therapeutic recombinant proteins is:

• Perfectly human glycosylation patterns
• Presence of non-human sequences, aggregates, or neo-epitopes created during rDNA manipulation
• High purity and monodispersity
• Use of human cell lines for production

Correct Answer: Presence of non-human sequences, aggregates, or neo-epitopes created during rDNA manipulation

Q16. Which technique can rapidly identify the variable region sequences from a single hybridoma clone for recombinant antibody expression?

• Southern blotting
• RT-PCR of mRNA followed by sequencing
• ELISA titering only
• Western blot with anti-mouse Fc

Correct Answer: RT-PCR of mRNA followed by sequencing

Q17. In upstream process optimization for recombinant biologics, codon optimization is performed to:

• Improve mRNA stability and translation efficiency in the chosen host species
• Remove signal peptides to retain protein intracellularly
• Add glycosylation sites indiscriminately
• Increase plasmid size beyond host capacity

Correct Answer: Improve mRNA stability and translation efficiency in the chosen host species

Q18. Which approach is commonly used to generate fully human monoclonal antibodies without hybridoma technology?

• Mouse hybridoma using mouse spleen cells only
• Phage display libraries or transgenic humanized mice
• E. coli expression of murine antibodies
• Random chemical conjugation of small molecules to IgG

Correct Answer: Phage display libraries or transgenic humanized mice

Q19. During downstream processing, which analytical test is essential to assess whether a recombinant therapeutic antibody retains its Fc effector function?

• Peptide mapping by trypsin digest alone
• ADCC bioassay or FcγR binding assay
• UV absorbance at 260 nm
• GC-MS of volatile impurities

Correct Answer: ADCC bioassay or FcγR binding assay

Q20. Which statement best describes why hybridoma-derived monoclonal antibodies may require humanization before therapeutic use in humans?

• Mouse antibodies are always too small to be effective in humans
• Mouse constant regions prevent antigen binding in humans
• Murine variable and constant regions can provoke human anti-mouse antibody (HAMA) responses, reducing efficacy and causing adverse reactions
• Humanization increases the non-human glycan content to improve half-life

Correct Answer: Murine variable and constant regions can provoke human anti-mouse antibody (HAMA) responses, reducing efficacy and causing adverse reactions

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