A student investigating immunity injects a mouse with a specific antigen. The mouse produces lymphocyte cells that make antibodies complementary to that antigen. The student then fuses the lymphocyte cells with tumour cells to produce hybridoma cells. Explain why the student fuses the lymphocyte cells with tumour cells, and describe what happens next to produce large numbers of monoclonal antibodies.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Monoclonal antibodies are used in diagnostic tests for diseases such as HIV and Chlamydia. They are produced in a laboratory using hybridoma cells.
Model answer (5 marks)
Lymphocyte cells alone cannot divide continuously and will die out.
Tumour cells divide continuously and indefinitely.
Fusion creates hybridoma cells that both divide continuously and produce the specific antibody.
Hybridoma cells producing the correct antibody are selected.
Selected hybridoma cells are cultured to produce large numbers of identical (monoclonal) antibodies.
Tumour cells divide continuously and indefinitely.
Fusion creates hybridoma cells that both divide continuously and produce the specific antibody.
Hybridoma cells producing the correct antibody are selected.
Selected hybridoma cells are cultured to produce large numbers of identical (monoclonal) antibodies.
Examiner tips
- Use the exact terms ‘lymphocyte’, ‘tumour’, ‘hybridoma’, ‘monoclonal antibodies’.
- Show the logical sequence: lack of division → fusion → continuous division + antibody production → selection → large‑scale culture.
- Keep each point brief and to the point to match the 5‑mark structure.
Common mistakes
- Confusing ‘tumour’ with ‘tumor’ (UK spelling required).
- Failing to mention that lymphocytes alone cannot divide continuously.
- Not specifying that the selected hybridoma cells are cultured to produce large numbers of identical antibodies.
Mark scheme (5 marks)
- Lymphocyte cells alone cannot divide continuously / will die out
- Tumour cells divide continuously / indefinitely
- Hybridoma cells both divide continuously AND produce the specific antibody
- Hybridoma cells producing the correct antibody are selected
- Selected hybridoma cells are cultured to produce large numbers of identical / monoclonal antibodies
Key terms in this question
monoclonal antibodies · hybridoma cells · lymphocyte · antigen
Related
- All WJEC A-Level Biology (Wales) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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