Vaccine production substrate: The standard mumps vaccine (e.g., Jeryl Lynn strain) is propagated in which type of cell culture for mass production?

Introduction / Context:
Live attenuated viral vaccines are grown in specific cell substrates to ensure safety, yield, and regulatory compliance. Mumps vaccine, part of the MMR formulation, has a well-established production history.

Given Data / Assumptions:

• Focus is on the routine production substrate for licensed mumps vaccine strains.
• Options list several animal cell sources.

Concept / Approach:
The Jeryl Lynn mumps strain is classically manufactured in chick embryo fibroblast cultures. This substrate supports viral replication and meets safety standards; it is also used for other licensed vaccines. While some older vaccines used primate cells, current standard mumps vaccine production uses chick embryo fibroblasts rather than monkey or mammalian livestock tissues.

Step-by-Step Solution:
Identify licensed mumps vaccine strain: Jeryl Lynn and derivatives. Recall standard substrate: chick embryo fibroblasts. Exclude primate and livestock options not used for routine mumps vaccine production. Select chick fibroblasts.

Verification / Alternative check:
Regulatory documents and manufacturer product information list chick embryo fibroblast culture as the substrate for many MMR components including mumps.

Why Other Options Are Wrong:

• African green monkey cells: used historically for some vaccines, but not the standard for mumps.
• Healthy calves and sheep: not used as primary cell substrates for the licensed mumps vaccine.

Common Pitfalls:
Assuming all live vaccines are grown in the same primate lines; substrates vary by virus and by regulatory approvals.

Final Answer:
chick fibroblasts