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.
Humoral immunity is called active when the organism generates its own antibodies, and passive when antibodies are transferred between individuals or species. Similarly, cell mediated immunity is active when the organismsâ own T-cells are stimulated, and passive when T cells come from another organism.