killer cell
Low (in general use); High (in medical/biological contexts)Technical, Medical, Scientific
Definition
Meaning
A type of white blood cell (lymphocyte) that can destroy infected or abnormal cells in the body.
Primarily refers to two main types: natural killer (NK) cells, which are part of the innate immune system, and cytotoxic T cells (killer T cells), which are part of the adaptive immune system. They induce apoptosis (programmed cell death) in target cells such as virus-infected cells or cancer cells.
Linguistics
Semantic Notes
Often used as a general term, but in precise contexts, the specific type (e.g., natural killer cell, cytotoxic T cell) is specified. The term 'killer' is a functional metaphor.
Dialectal Variation
British vs American Usage
Differences
No significant orthographic or pronunciation differences. The term is used identically in both varieties.
Connotations
Identical technical and neutral connotations in both varieties.
Frequency
Equally common in medical and scientific discourse in both the UK and US.
Vocabulary
Collocations
Grammar
Valency Patterns
[Adjective] + killer cell (e.g., activated killer cell)killer cell + [of/against] + [noun] (e.g., killer cells of the immune system)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Almost never used, except in biotech/pharma company reports.
Academic
Common in immunology, biology, and medical textbooks and research papers.
Everyday
Rare; might appear in simplified health news articles about cancer or immunity.
Technical
The primary register. Precisely defined in immunology contexts.
Examples
By Part of Speech
adjective
British English
- The killer-cell response was measured.
- killer-cell activity
American English
- The killer cell response was measured.
- killer cell activity
Examples
By CEFR Level
- Doctors say our bodies have cells that fight germs.
- Killer cells are an important part of the body's defence system.
- Natural killer cells can attack virus-infected cells without prior exposure.
- The research focused on enhancing cytotoxic T killer cell activity against solid tumours.
Learning
Memory Aids
Mnemonic
Imagine a tiny 'cell' in your body that is a trained 'killer' of sick or dangerous cells, like a microscopic security guard.
Conceptual Metaphor
THE IMMUNE SYSTEM IS AN ARMY (where killer cells are soldiers/assassins).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not translate 'killer' as 'убийца' in isolation, as it carries a criminal connotation. The established biological term is 'киллерная клетка' or 'естественный киллер' (for NK cell).
- Avoid confusion with the loanword 'киллер' (hitman); the biological metaphor is the same, but the context is entirely scientific.
Common Mistakes
- Using 'killer cell' as a general term for any harmful cell (e.g., a cancer cell) rather than for the immune cell that kills it.
- Confusing 'killer T cells' (adaptive immunity) with 'natural killer cells' (innate immunity).
Practice
Quiz
What is the primary function of a 'killer cell'?
FAQ
Frequently Asked Questions
No, they are distinct. Killer T cells (cytotoxic T lymphocytes) are part of the adaptive immune system and require prior exposure to a specific antigen. Natural killer (NK) cells are part of the innate immune system and can act more immediately against a wider range of threats.
Yes, an overactive or misdirected killer cell response can contribute to autoimmune diseases, where the immune system attacks the body's own healthy tissues.
It is a standard and formal term in immunology, though in precise writing, scientists often use the more specific terms 'cytotoxic T cell' or 'natural killer (NK) cell'.
They use complex receptor systems to detect signals on the surface of other cells. For example, they look for the absence of 'self' markers (MHC class I molecules) or the presence of 'stress' signals, which indicate infection or abnormality.