Examples of Natural killer cells (or NK cells) in the following topics:
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- Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
- Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
- NK cells differ from Natural Killer T cells (NKT) phenotypically, by origin, and by respective effector functions.
- Natural killer cells are not only effectors of innate immunity; recent research has also uncovered information on both activating and inhibitory NK cell receptors, which play roles in maintaining self-tolerance and sustaining NK cell activity.
- Natural killer cell activation is determined by the balance of inhibitory and activating receptor stimulation—for example, if the inhibitory receptor signaling is more prominent, then NK cell activity will be inhibited.
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- Natural killer cells are part of the innate immune response that recognize abnormal MHC I molecules on infected/tumor cells and kill them.
- After a pathogen enters the body, infected cells are identified and destroyed by natural killer (NK) cells, which are a type of lymphocyte that can kill cells infected with viruses or tumor cells (abnormal cells that uncontrollably divide and invade other tissue).
- This process can deplete host MHC I molecules on the cell surface, which prevents T-cells from recognizing them, but which NK cells detect as "unhealthy" or "abnormal" while searching for cellular MHC I molecules.
- After the NK cell detects an infected or tumor cell, its cytoplasm secretes granules comprised of perforin: a destructive protein that creates a pore in the target cell.
- Describe the role of natural killer cells in the immune response
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- Natural Killer (NK) cells are cytotoxic lymphocytes critical for the innate immune system.
- Natural killer cells (NK cells) are cytotoxic lymphocyte critical to the innate immune system.
- They were named "natural killers" because they were originally thought to not require cytokine or chemokine activation to be work, however later research proved that cytokines play a role in guiding NK cells to stressed cells that may need to be destroyed.
- NK cells are activated in response to interferons or macrophage-derived cytokines.
- Describe the role of natural killer cells in the innate immune system
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- The three major types of lymphocyte are T cells, B cells, and natural killer cells.
- Natural killer (NK) cells are part of the innate immune system and play a major role in defending the host from both tumors and virus-infected cells.
- Normal cells express MHC class I on their cell membranes, while infected or cancerous cells do not express or express reduced amounts of the molecule.
- Activated NK cells release cytotoxic (cell-killing) granules that contain perforin and granzyme, which can lyse (break down) cell membranes and induce apoptosis to kill infected or abnormal cells.
- If cancer cells evade NK cell detection for long enough, however, they can grow into tumors that are more resistant to NK cell activity.
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- T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes.
- These two cell types can function independently or cooperatively to defend the body against pathogens.
- T-lymphocytes can be distinguished from other lymphocytes like B cells and natural killer cells (NK cells) by the presence of a T cell receptor (TCR) on the cell surface.
- Alternatively, B-cells can be distinguished from other lymphocytes like T cells and natural killer cells (NK cells) by the presence of a protein on the B-cell's outer surface called a B-cell receptor (BCR).
- T-lymphocytes express CD3, CD4, CD8, or CD25 markers.
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- It also refers to NK cells of the innate immune system as well.
- There are two main types of T cells, that express either CD4 or CD8 depending on signals that occur during T cell maturation, but there are other subdivisions of T cells that are less common.
- They function similarly to natural killer cells by binding to
MHC class I and releasing perforin, granzymes, and proteases to induce apoptosis in a pathogen.
- They are different from NK cells because they will only bind to
cells that express the antigen that they are specific to, and they are not large or granular like NK cells are.
- Besides antibody production, B cells may also function in antigen presentation, though not to the degree of macrophages or dendritic cells.
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- Cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
- Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or serum) and cellular immunity, for which the protective function of immunization was associated with cells.
- CD4 cells or helper T cells provide protection against different pathogens.
- 2. activating macrophages and natural killer cells, enabling them to destroy pathogens
- If a person has had a history of a positive tuberculin skin test, or had a recent tuberculin skin test (within one year), another skin test should be used.
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- First, an antigen-presenting cell (APC, such as a dendritic cell or a macrophage) detects, engulfs (via phagocytosis in the case of macrophages or by entry of the pathogen of its own accord in the case of dendritic cells), and digests pathogens into hundreds or thousands of antigen fragments.
- After a virus or bacteria enters a cell, it can no longer be detected by the humoral immune response.
- TC cells also support NK lymphocytes to destroy early cancers.
- Cytokines are signaling molecules secreted by a TH cell in response to a pathogen-infected cell; they stimulate natural killer cells and phagocytes such as macrophages.
- Depending on the cytokines released, this activates either the humoral or the cell-mediated immune response.
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- T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in the cell-mediated branch of the adaptive immune system.
- They can be distinguished from other lymphocytes, such as B cells and natural killer cells (NK cells), by the presence of a T cell receptor (TCR) on the cell surface.
- T cells can be either helper T cells or cytoxic T cells based on whether they express CD4 (helper) or CD8 (cytotoxic) glycoprotein.
- A thymocyte's differentiation into helper or cytotoxic versions is also determined during positive selection.
- This process is an important component of central tolerance, or the ability for immune cells to not attack parts of the "self", and serves to prevent the formation of self-reactive T cells that are capable of inducing autoimmune diseases in the host.
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- This involves immune cells such as the natural killer cells (NK cells), lymphokine-activated killer cells (LAK cells), cytotoxic T lymphocytes (CTLs), and dendritic cells (DC).
- In spite of this fact, however, many kinds of tumor cells display unusual antigens that are inappropriate for either the cell type or its environment or that are only normally present during the organism's development (e.g. fetal antigens).
- Adoptive cell-based immunotherapy involves isolating either allogenic or autologous immune cells, enriching them outside the body, and transfusing them back to the patient.
- Topical immunotherapy utilizes an immune enhancement cream (imiquimod), which is an interferon producer, causing the patient's own killer T cells to destroy warts, actinic keratoses, basal cell carcinoma, squamous cell carcinoma, cutaneous T cell lymphoma, and superficial spreading melanoma.
- The relatively tumor-specific expression of GD2 makes it a suitable target for immunotherapy with monoclonal antibodies or with artificial T-cell receptors.