Cell culture — Which of the following are continuous (immortal) human cell lines used in virology labs?
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AHeLa
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BHEp-2
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CKB
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DAll of these
Answer
Correct Answer: All of these
Explanation
Introduction / Context:Choosing the right cell line is critical for virus isolation and research. Continuous (immortal) lines divide indefinitely under culture, unlike primary or semi-continuous diploid strains that senesce after limited passages.
Given Data / Assumptions:
- HeLa (cervical carcinoma), HEp-2 (laryngeal/epithelial carcinoma), and KB (epithelial carcinoma) are widely cited.
- Continuous lines are aneuploid and immortal.
Concept / Approach:HeLa, HEp-2, and KB are classic continuous human lines, commonly permissive for a range of human viruses. In contrast, semi-continuous diploid lines include WI-38 and MRC-5, which have finite lifespans and near-diploid karyotypes.
Step-by-Step Solution:
Identify each listed line as continuous/immortal.Note broad laboratory use for cytopathic-effect assays and neutralization tests.Therefore, select “All of these.”Verification / Alternative check:Standard virology manuals categorize these three as continuous lines used for viral culture and research.
Why Other Options Are Wrong:
- HeLa alone, HEp-2 alone, or KB alone: each is true but incomplete; the grouping answer captures all correct cases.
Common Pitfalls:Confusing continuous lines with human diploid strains like WI-38/MRC-5; the latter are not immortal.
Final Answer:All of these