Cell lysis refers to the breaking down or destruction of a cell by an external force or condition. It can happen through natural means such as a viral infection or through artificial means for research purposes. The resulting fluid containing the contents of the lysed cells is called a lysate. Lysin is a substance that causes lysis.
Osmosis is one of the most common causes of cell lysis in animal and plants. In cytolysis, the concentration of salt within the cell is higher than its surroundings, so water flows into the cell through osmosis causing the cell to burst. On the other hand, in plasmolysis, water flows out of the cell due to evaporation or a high salt concentration outside of the cell. Eventually the cell undergoes lysis as it shrivels and dies. Plasmolysis is particularly common in plant cells which often lose significant amounts of water because of hot, dry conditions.
Another case of cell lysis may be due to a direct toxin or animmune mechanism, such as antibody reacting with antigen on the surface of a target cell, usually by binding and activation of a series of proteins in the blood with enzymatic activity.
Other examples of cell lysis include haemolysis, bacteriolysis and nephrolysis.