What does cytolytic mean?
"Cytolytic" is a technical adjective describing something that destroys cells by lysis — the rupture of the cell's outer membrane, causing the cell to burst and its contents to spill out. The term appears most often in immunology, where cytolytic T cells and natural killer cells are credited with eliminating virus-infected or cancerous cells by punching lethal holes in their targets. It also features in virology, where some viruses are described as cytolytic because they kill host cells as they replicate, and in medicine, where a "cytolytic" pattern of elevated liver enzymes signals direct hepatocyte injury. Because it refers specifically to destructive, membrane-breaking cell death, it contrasts with terms like "cytotoxic," a broader label for anything harmful to cells. Precise and evocative, the word captures the immune system's most aggressive mode of action and remains essential vocabulary in biomedical science.
adjectiveRelating to or causing the destruction or dissolution of cells, especially through rupture of their outer membrane. In immunology, it describes agents — such as certain T cells, natural killer cells, antibodies, or drugs — that kill target cells in this way.
- Relating to or causing the lysis (rupture and dissolution) of cells; used chiefly of immune cells, antibodies, viruses, or substances that destroy cells this way.
"Cytolytic T cells eliminate virus-infected cells by releasing perforin and granzymes that puncture their membranes."
"The assay measured the cytolytic activity of natural killer cells against tumor targets."
"Elevated liver enzymes suggested a cytolytic pattern of drug-induced injury."
A single cytolytic T cell can serially kill multiple infected targets in a matter of hours — your immune system's own precision assassins at work.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cytolytic
Cytolytic derives from Greek roots: "kytos" meaning hollow vessel or cell, combined with "lysis," meaning loosening or dissolution. The compound reflects nineteenth-century scientific Greek, assembled as microscopy revealed cellular structure and biologists needed precise vocabulary for cell breakdown. It shares these elements with a family of biomedical terms built on the same roots, such as cytoplasm and lysosome, and belongs to the wider class of "-lytic" adjectives describing dissolving or destroying agents.
Related word forms
How cytolytic is actually used
Strictly technical register: found almost exclusively in immunology, virology, pathology, and pharmacology literature rather than everyday speech. In hepatology, "cytolytic" often describes a laboratory injury pattern (marked transaminase elevation), which differs subtly from its immunological use.
Easily confused with cytolytic
Cytotoxic broadly means toxic to cells (including by metabolic damage or apoptosis), whereas cytolytic specifically denotes destruction by physical rupture or lysis of the cell membrane.
Apoptotic describes orderly programmed cell death with the cell breaking into contained fragments, while cytolytic death is a more violent bursting of the membrane that releases contents.