A unit of weight equal to 2,000 pounds (0.907 metric ton or 907.18 kilograms). Also called net ton, short ton. 2. A unit of weight equal to 2,240 pounds (1.016 metric tons or 1,016.05 kilograms). Also called long ton.
Cellular immunity is a protective immune process that involves the activation of phagocytes, antigen-sensitized cytotoxic T cells and the release of cytokines and chemokines in response to antigen. Cellular immunity is most effective against cells infected with viruses, intracellular bacteria, fungi and protozoans, and cancerous cells.
It is part of the adaptive immune system, which is activated in response to a specific threat, as opposed to the innate immune system, which is continually active but less effective. The other part of the adaptive system is cellular, or cell-mediated, immunity, in which cells release toxins to kill invaders or attack them directly, without the involvement of antibodies.