Our body has cells that control immunity or eat up germs to protect the body against pathogens, foreign materials or viruses. These are called immune cells or immunocytes.
Functions of Natural Killer Cell (NK Cell)
When recognizing tumor-specific antigens, activated natural killer cells (NK cell) either engulf cancer cells or release cytotoxic materials by forming pores in the membrane of the target cancelr cells, inducing cell killing. By doing so, NK cells selectively target and destroy cancer cells while sparing normal cells in our body.
When attacking abnormal cells such as cancer cells, NK cells release protein, called perforin, to form pores in the membrane of the cancer cell through which the granzymes can enter, inducing apoptosis.
Types of Immunocytes
There are a variety of immune cells, including NK cells, T cells, B cells, dendritic cells and so forth. NK cells are capable of identifying and selectively destroying cancer cells. B-cells coordinate the forming of antibodies against specific pathogens. T cells facilitate the forming of antibodies in response to specific infection by remembering information on the immune response. Dendritic cells, named after their shape resembling a finger or dendrite, present antigens to T cells for activating the immune system. These immune cells protect our body from outside invaders through active immune responses.
NK cell plays an important role in the innate immune system. They are known to attack virus-infected cells or tumor cells. When detecting abnormal cells, they release perforin on the membrane of the target cell to form pores by melting the membrane, And then, they secrete granzymes on the membrane to dissolve cytoplasm or inject water and salinity inside the cell for inducing apoptosis. When they identify cancer cells, they can directly attack the cancer cells or activate cytotoxic T cells or B cells to indirectly attack the cancer cells by releasing cytokines.
T cell or T lymphocyte is a type of lymphocyte specific for particular antigens, playing a key role in the adaptive immune system. They directly kill abnormal cells or help B cells to produce antibodies, orchestrating the immune response. When T cell loses it functions, Acquired Immune Deficiency Syndrome (AIDS) might develop.
B cell is a type of lymphocyte making antibodies. They produce antibodies in response to invading antigens.
Dendritic cell is a type of antigen-presenting cells, protecting the body from invading viruses. The name of dendritic cell is based on its shape that resembles a branch. They are major antigen-presenting cells spread beneath the skin and induce T-cell differentiation in thymus.
Macrophage is a cell involved in the immune system, residing in every tissue of the body.
They engulf and digest invaders such as germs, and present antigens to lymphocytes.