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Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.. A cytotoxic T cell (also known as T C, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8 + T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracellular pathogens such as viruses or bacteria, or ...
They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infected with viruses or bacteria. [1] Granzymes also kill bacteria [2] and inhibit viral replication. In NK cells and T cells, granzymes are packaged in cytotoxic granules along with perforin. Granzymes can also be ...
Activated effector T cells can be placed into three functioning classes, detecting peptide antigens originating from various types of pathogen: The first class being 1) Cytotoxic T cells, which kill infected target cells by apoptosis without using cytokines, 2) T h 1 cells, which primarily function to activate macrophages, and 3) T h 2 cells ...
Natural killer cells, also known as NK cells, are a type of cytotoxic lymphocyte critical to the innate immune system.They are a kind of large granular lymphocytes [1] [2] (LGL), and belong to the rapidly expanding family of known innate lymphoid cells (ILC) and represent 5–20% of all circulating lymphocytes in humans. [3]
Once the Fc receptor binds to the Fc region of the antibody, the NK cell releases cytotoxic factors that cause the death of the target cell. During replication of a virus, some of the viral proteins are expressed on the cell surface membrane of the infected cell. Antibodies can then bind to these viral proteins.
Upon fusing with the cancer cell, the macrophages (smaller white cells) inject toxins that kill the tumor cell. Immunotherapy for the treatment of cancer is an active area of medical research. [141] The main response of the immune system to tumors is to destroy the abnormal cells using killer T cells, sometimes with the assistance of helper T ...
CD8 + T cells, also known as "killer T cells", are cytotoxic – this means that they are able to directly kill virus-infected cells, as well as cancer cells. CD8 + T cells are also able to use small signalling proteins, known as cytokines , to recruit other types of cells when mounting an immune response.
In addition to activating M1 macrophages, T H 1 cells express Fas ligand (FasL) and lymphotoxin beta (LT-β) to help kill chronically infected macrophages that can no longer kill pathogens. [34] The killing of chronically infected macrophages release pathogens to the extracellular space that can then be killed by other activated macrophages. [34]