Permissivity and lytic infection in SV40 In which cell type does a lytic infection by SV40 fail to occur?

Introduction / Context:Small DNA tumor viruses such as SV40 show host-range and cell-type specificity. Whether infection proceeds to lytic replication or is abortive depends on availability of host factors and compatibility for viral gene expression. This concept underlies the use of permissive cell lines and transformation studies.

Given Data / Assumptions:

• SV40 requires specific host machinery and temperature/condition suitability for productive replication.
• Permissive cells support full lytic cycle and virion production.
• Non-permissive cells restrict productive replication.

Concept / Approach:By definition, permissive cells allow productive viral replication and lytic infection. Non-permissive cells do not permit the complete lytic cycle; infection may result in limited gene expression, integration, or transformation-like outcomes without virion production. Therefore, lytic infection does not occur in non-permissive cells.

Step-by-Step Solution:

Verification / Alternative check:Classic SV40 studies distinguish permissive monkey cells (productive lytic replication) from non-permissive rodent cells (abortive replication and transformation).

Why Other Options Are Wrong:

• Permissive cells: by definition support lytic growth.
• Both/none: contradict core definitions.
• Large T overexpression: tends to enhance early functions; not a category where lytic infection is absent by definition.

Common Pitfalls:Equating viral entry with successful lytic replication; entry can occur without permissive replication.

Final Answer:Non-permissive cells