Summary
Innate lymphocytes that destroy virus-infected and tumour cells lacking normal MHC markers.
In depth
They use activating and inhibitory receptors; cells missing MHC I (the 'missing self' state) are killed by perforin and granzymes. They also kill antibody-coated cells (ADCC).
NK cells need no prior sensitisation. They are important early against viruses and tumours. Cytokine (IL-2, IL-15) activation increases cytotoxicity.
Key idea: they detect altered self rather than specific antigens.
Frequently asked questions
What is Natural Killer Cells?
Innate lymphocytes that destroy virus-infected and tumour cells lacking normal MHC markers.
Which area of biology covers Natural Killer Cells, and how advanced is it?
Natural Killer Cells is one of the 52 topics in Immunology & Disease. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Adaptive Immunity, Innate Immunity, Innate Lymphoid Cells.
Can you give an example of Natural Killer Cells?
Some viruses downregulate MHC I to evade T cells but become vulnerable to NK cells.
What should I learn before Natural Killer Cells?
Work through the Beginner topics in Immunology & Disease first, such as Immune System, Viruses, Innate Immunity, then return to Natural Killer Cells. Intermediate topics assume the Beginner vocabulary.
What topics are related to Natural Killer Cells?
The closest topics to Natural Killer Cells are Adaptive Immunity, Innate Immunity, Innate Lymphoid Cells, Complement System. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Natural Killer Cells?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Natural Killer Cells. To practise the whole of Immunology & Disease, use the Immunology & Disease quiz.
How is Natural Killer Cells different from Adaptive Immunity?
Natural Killer Cells: Innate lymphocytes that destroy virus-infected and tumour cells lacking normal MHC markers. Adaptive Immunity: Slower, specific defence involving lymphocytes that remember pathogens. Read both side by side and note what each one explains.
How should I study Natural Killer Cells step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Adaptive Immunity and explain the difference aloud. Finally, take the Immunology & Disease quiz and come back to this page for any question you miss.