Describe the steps used to produce monoclonal antibodies in a laboratory.

Eduqas A-Level Biology — 3.3 Microbiology · Describe · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (5 marks)

1. A specific antigen is injected into an animal, usually a mouse.
2. The animal mounts an immune response; B‑cell lymphocytes that recognise the antigen are harvested.
3. The harvested lymphocytes are fused with tumour (myeloma) cells to create hybridoma cells.
4. Hybridoma cells inherit the ability to divide indefinitely from the tumour cells and the antibody‑producing ability from the lymphocytes.
5. Hybridomas that secrete the desired antibody are selected and cultured to produce large quantities of monoclonal antibodies.

Examiner tips

  • Use the exact sequence of steps; include both fusion and selection stages.
  • Show that hybridomas combine unlimited growth with specific antibody production.
  • Mention the animal and antigen injection as the starting point.
  • Keep the answer concise and use the terminology "hybridoma" and "monoclonal antibodies".

Common mistakes

  • Omitting the fusion with tumour cells or the selection of correct hybridomas.
  • Confusing polyclonal with monoclonal antibodies.
  • Using vague terms like "immune cells" instead of "B‑cell lymphocytes".

Mark scheme (5 marks)

  1. A specific antigen is injected into an animal (e.g. a mouse)
  2. The animal produces an immune response and lymphocyte cells are removed from the animal
  3. The lymphocyte cells are fused with tumour cells to produce hybridoma cells
  4. Hybridoma cells can both divide continuously (indefinitely) AND produce antibodies
  5. Hybridoma cells producing the correct antibody are selected and cultured to produce large quantities of monoclonal antibodies

Key terms in this question

monoclonal antibodies

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