11.2.2—Hybridoma method

A hybridoma is a fused cell line used to produce large quantities of one monoclonal antibody. It combines an antibody-producing B-cell lineage with a tumour-cell lineage that can continue dividing.

1. Stimulate antibody production: Inject an animal with the relevant antigen so specific antibody-producing B lymphocytes, including plasma-cell descendants, are generated.
2. Isolate antibody-producing cells: Remove the stimulated B-cell population from the animal.
3. Fuse cell types: Fuse the B cells with tumour cells to form hybridoma cells. The fused cell combines antibody specificity from the B-cell lineage with the capacity for continued mitotic division from the tumour-cell lineage.
4. Select and screen: Grow the fusion products in selective medium, then test the surviving hybrid cells for production of the desired antibody. Selection alone does not prove the antibody has the required specificity.
5. Clone and expand: Isolate a hybridoma producing the desired antibody, clone that line, and culture it to produce large quantities of identical monoclonal antibody.

The sequence matters: antigen stimulation supplies specificity; fusion supplies a hybrid cell with both antibody production and sustained division; selection removes unsuitable fusion products; screening identifies the required specificity; cloning preserves one antibody-producing cell line for expansion.

This card explains how monoclonal antibodies are made. Their diagnostic and therapeutic uses belong to the next objective; the broader primary immune-response sequence belongs to the neighbouring immune-response card.