In cell biology, an effector cell is any of various types of

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

that actively responds to a

stimulus A stimulus is something that causes a physiological response. It may refer to: *Stimulation **Stimulus (physiology), something external that influences an activity **Stimulus (psychology), a concept in behaviorism and perception *Stimulus (economi ...

and effects some change (brings it about). Examples of effector cells include: * The muscle, gland or organ cell capable of responding to a stimulus at the terminal end of an

efferent nerve fiber Efferent nerve fibers refer to axonal projections that ''exit'' a particular region; as opposed to afferent projections that ''arrive'' at the region. These terms have a slightly different meaning in the context of the peripheral nervous syste ...

* Plasma cell, an effector B cell in the immune system *

Effector T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell re ...

s, T cells that actively respond to a stimulus * Cytokine-induced killer cells, strongly productive cytotoxic effector cells that are capable of lysing tumor cells * Microglia, a glial effector cell that reconstructs the

Central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

after a bone marrow transplant * Fibroblast, a cell that is most commonly found within connective tissue *

Mast cell A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a par ...

, the primary effector cell involved in the development of asthma

Cytokine-induced killer cells as effector cells

As an effector cell, cytokine-induced killer cells can recognize infected or

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

cells even when antibodies and major histocompatibility complex (MHC) are not available. This allows a quick immune reaction to take place. Cytokine-Induced killer (CIK) cells are important because harmful cells that do not contain MHC cannot be traced and removed by other immune cells. CIK cells are being studied intensely as a possible therapy treatment for cancer and other types of viral infections. CIK cells respond to lymphokines by lysing tumorous cells that are resistant to NK cells or LAK cell activity. CIK cells show a large amount of cytotoxic potential against various types of tumors. Side effects of CIK cells are also considered very minor. In a few cases, CIK cell treatment lead to the complete disappearance of tumor burdens, extended periods of survival, and improved quality of life, even if the cancerous tumor cells were in advanced stages. At the moment, the exact mechanism of tumor recognition in CIK cells are not completely understood.

Fibroblast as effector cells

Fibroblast are types of cells that form the extracellular matrix and collagen. Fibroblasts are the most common connective tissues in animals. They have branched cytoplasm surrounding their nucleus, which contain two or more nucleoli. Fibroblasts play a key role when responding to tissue injury. They initiate inflammation in the presence of foreign microorganisms. Receptors found on the surface of fibroblasts regulate hematopoietic cells, start chemokine synthesis, and provide a pathway that allows immune cells to regulate the fibroblast cells. Fibroblasts are also known as tumor mediators. They suppress the tumor as an inflammatory response.

Microglia as effector cells

Microglia are located throughout the brain and spinal cord. They are the first line of immune defense in the CNS. Microglia are of utmost importance in brain maintenance. They constantly search around the CNS for any type of plaques, damaged neurons, and infections. Microglia are extremely sensitive forms of effector cells, because they must be alert enough to address possible life-threatening damage. This sensitivity is caused by unique forms of potassium channels. Microglia must always be capable of recognizing any foreign bodies, engulf them, and activate T-cells. Microglia can be found under a variety of different shapes and sizes, based on the location where they are found. The vast amount of shapes are required for the microglia to carry out their primary function. Microglia are distinguishable from macrophages because of their ability to transform, which allows them to protect the CNS under relatively short amounts of time. Microglia take on a unique phenotype when they detect local chemical signals. Microglia have a variety of different functions required to maintain homeostasis in the host body.

Mast cells as effector cells

A mast cell is a white blood cell. Mast cells are protective cells that are involved in wound healing and blood-brain barrier function. Mast cells are very similar to basophils, and mast cells once were mistaken for them. It is proven that the two cells have different lineages.{{Cite journal, last1=Franco, first1=Christopher B., last2=Chen, first2=Ching-Cheng, last3=Drukker, first3=Micha, last4=Weissman, first4=Irving L., last5=Galli, first5=Stephen J., date=2010-04-02, title=Distinguishing mast cell and granulocyte differentiation at the single cell level, journal=Cell Stem Cell, volume=6, issue=4, pages=361–368, doi=10.1016/j.stem.2010.02.013, issn=1934-5909, pmc=2852254, pmid=20362540 Mast cells respond to pathogenic parasites through Immunoglobin E signaling. These cells play a role in the inflammatory process. They can either release selective amounts or rapid amounts of compounds that induce inflammation from granules. Mast cells are inactive during allergic reactions unless an allergen binds to Immunoglobin E.

References

Cellular processes Cell signaling