Cell culture — Which of the following is a semi-continuous human diploid cell line commonly used in virology?
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AHeLa
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BHEp-2
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CWI-38
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DKB
Answer
Correct Answer: WI-38
Explanation
Introduction:Human cell lines are categorized as primary, semi-continuous (diploid), or continuous (immortalized). This question assesses knowledge of classic lines used for viral isolation and vaccine research.
Given Data / Assumptions:
- HeLa, HEp-2, and KB are well-known continuous lines.
- WI-38 is a human diploid fibroblast strain.
- Semi-continuous lines retain finite lifespan and normal karyotype features.
Concept / Approach:Diploid strains such as WI-38 and MRC-5 are finite lines with limited passages and near-diploid chromosomes, making them suitable for certain vaccine production steps and for maintaining differentiated properties relative to immortalized lines.
Step-by-Step Solution:
Identify which option is human diploid: WI-38.Exclude HeLa (immortal cervical carcinoma).Exclude HEp-2 (carcinoma-derived, continuous).Exclude KB (epithelial carcinoma line).Verification / Alternative check:Standard virology references list WI-38 and MRC-5 as semi-continuous diploid fibroblasts with finite passage numbers, used historically for certain vaccines.
Why Other Options Are Wrong:
- HeLa: continuous, aneuploid, immortal.
- HEp-2: continuous human epithelial line.
- KB: continuous carcinoma line.
Common Pitfalls:Assuming all frequently used lines are diploid; many popular lines are immortalized and continuous.
Final Answer:WI-38