Cell fusion propensity: When deriving monoclonal antibodies, lymphocytes from lymph nodes or tonsils are especially valuable if their fusion tendencies are at what level?

Introduction / Context:
Hybridoma formation depends on the efficiency with which primary lymphocytes fuse with immortal partner cells. Tissues rich in activated B cells, such as tonsils or draining lymph nodes after antigen exposure, can yield higher fusion efficiencies, improving chances of obtaining antigen-specific clones.

Given Data / Assumptions:

• Fusion frequency is a limiting factor in hybridoma workflows.
• Activated, proliferating lymphocytes tend to fuse more readily than resting cells.
• Higher fusion rates directly translate to more hybridoma candidates.

Concept / Approach:
When screening for successful fusions in selective media, starting with lymphocytes that exhibit high fusion frequencies maximizes recovery of desired clones. Hence, lymph node or tonsil-derived B cells, often enriched for antigen-experienced cells, are preferred tissue sources.

Step-by-Step Solution:

Verification / Alternative check:
Empirical lab experience shows antigen-stimulated tissues produce more successful fusions than peripheral blood with resting lymphocytes.

Why Other Options Are Wrong:

Common Pitfalls:
Underestimating the importance of starting cell source and activation status on fusion outcomes.

Final Answer:
High frequencies (fuse readily).