Cell, T-4

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Cell, T-4

Cell, T-4

A type of T cell that has CD4 markers on its surface and participates in the immune response by recognizing foreign antigens and secreting substances called cytokines that activate T and B cells. T-helper cells fall into two main classes: those that activate other T cells to achieve cellular inflammatory responses; and those that drive B cells to produce antibodies in the humoral immune response. These two classes of response are generally incompatible with one another and require coordination by substances called cytokines to promote one response while dampening the other.

RELATED TERMS
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Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.

Immune
Resistant to a particular disease.

Antigens
Substances that cause an immune response in the body. The body "sees" the antigens as harmful or foreign. To fight them, the body produces antibodies, which attack and try to eliminate the antigens.

Cytokines
Peptides which regulate cellular growth, differentiation and activation.

Drive
Basic urge, instinct, motivation; a term used to avoid confusion with the more purely biological concept of instinct.

Antibodies
Proteins produced by white blood cells. They confer immunity.

SIMILAR TERMS
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Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.

Cell cloning
The process of producing a group of cells (clones), all genetically identical, from a single ancestral cell.

Cell cycle
The reproductive stages of a cell leading to cell division (mitosis).

Cell fusion
The melding of two or more cells into one cell called a heterokaryon. A heterokaryon may reproduce itself for at least several generations. Cell fusion provides a method for assigning specific genes to specific chromosomes.

Cell line
A general term applied to a defined population of cells that has been maintained in culture for an extended period and usually has undergone a spontaneous process, called transformation, that allows the cells to continue dividing (replicating) in culture indefinitely.

Cell lineage
A genealogic pedigree of cells related through mitotic division.

Cell memory
If foreign substances (e.g. bacteria) enter the body, the immune system reacts by attacking and killing them. At the same time, T-cells and B-cells produce a population of memory cells. If you are subsequently exposed to the same bacteria, the immune system reacts much more quickly. In allergy, this mechanism is called "priming". You do not experience an allergic reaction the first time you are exposed to a particular allergen, but your body registers the allergen and, over time, you may develop an allergy to it.

Cell nucleus
An organelle, found in most eukaryotic cells, which contains most of the cell's genetic material. Nuclei have two primary functions: to control chemical reactions within the cytoplasm and to store information needed for cellular division. Plural: nuclei.

Cell sorter, fluorescence-activated
A flow cytometer (a scientific instrument used to measure the characteristics of individual cells) that is modified for the purpose of separating (sorting) cells based on the amount of light (fluorescence) emitted by each cell.

Cell therapy
Treatment with cells. A technology that relies on replacing diseased or dysfunctional cells with healthy, functioning ones.

Cell, alpha (pancreatic)
A type of cell in the pancreas (the organ of the digestive system located behind the stomach). Within the pancreas, the alpha cells are located in areas called the islets of Langerhans. Alpha cells make and release glucagon which raises the level of glucose (sugar) in the blood.

Cell, antigen-presenting
A cell that can "present" antigen in a form that T cells can recognize it. The cells that can "present" antigen include B cells and cells of the monocyte lineage (including macrophages).

Cell, beta (pancreatic)
A type of cell in the pancreas (the organ of the digestive system located behind the stomach). Within the pancreas, the beta cells are located in areas called the islets of Langerhans. They constitute the predominant type of cell in the islets. The beta cells are important because they make insulin. Degeneration of the beta cells is the main cause of type I (insulin-dependent) diabetes mellitus.

Cell, cone
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provide sharp central vision and color vision.

Cell, delta (pancreatic)
A type of cell in the pancreas (the organ of the digestive system located behind the stomach). Within the pancreas, the delta cells are located in areas called the islets of Langerhans. The delta cells make somatostatin, a hormone that inhibits the release of numerous hormones in the body.

Cell, fat
A cell containing fat. Also called an adipocyte.

Cell, helper
A type of T cell that participates in the immune response by recognizing foreign antigens and secreting substances called cytokines that activate T and B cells. Helper cells fall into two main classes: those that activate other T cells to achieve cellular inflammatory responses; and those that drive B cells to produce antibodies in the humoral immune response. These two classes of response are generally incompatible with one another and require coordination by substances called cytokines to promote one response while dampening the other.

Cell, plasma
A type of white blood cell that produces and secretes antibodies. A plasma cell is a fully differentiated lymphocyte in the B-cell (not the T-cell) lineage. As with most cell types, plasma cells can mutate to give rise to cancer. Plasma cell malignancies include multiple myeloma, Waldenstrom macroglobulinemia, and plasma cell leukemia.

Cell, rod
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides side vision and the ability to see objects in dim light (night vision).

Cell, stem
An ancestral cell, the most primitive type of cell.

Cell, totipotent
A cell with the capacity to form an entire organism.

Cell-mediated cytotoxicity (CMC)
Killing (lysis) of a target cell by an effector lymphocyte.

Cell-mediated immunity (CMI)
Immune reaction mediated by T cells; in contrast to humoral immunity, which is antibody mediated. Also referred to as delayed-type hypersensitivity.

Cellcept
Cellcept is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): mycophenolate mofetil.

Cells, germ
The eggs and sperm are the germ cells: the reproductive cells. Each mature germ cell is haploid in that it has a single set of 23 chromosomes containing half the usual amount of DNA and half the usual number of genes.

Cells, reproductive
The eggs and sperm are the reproductive cells. Each mature reproductive cell is haploid in that it has a single set of 23 chromosomes containing half the usual amount of DNA.

Cellulite
An inflammation of the connective tissue underlying the skin that can be caused by a bacterial infection. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, burns, insect bites, surgical wounds, or sites of intravenous catheter insertion.

Cellulitis
An inflammation of the connective tissue underlying the skin that can be caused by a bacterial infection. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, burns, insect bites, surgical wounds, or sites of intravenous catheter insertion.

PREVIOUS AND NEXT TERMS
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Cell, fat
A cell containing fat. Also called an adipocyte.

Cell, helper
A type of T cell that participates in the immune response by recognizing foreign antigens and secreting substances called cytokines that activate T and B cells. Helper cells fall into two main classes: those that activate other T cells to achieve cellular inflammatory responses; and those that drive B cells to produce antibodies in the humoral immune response. These two classes of response are generally incompatible with one another and require coordination by substances called cytokines to promote one response while dampening the other.

Cell, plasma
A type of white blood cell that produces and secretes antibodies. A plasma cell is a fully differentiated lymphocyte in the B-cell (not the T-cell) lineage. As with most cell types, plasma cells can mutate to give rise to cancer. Plasma cell malignancies include multiple myeloma, Waldenstrom macroglobulinemia, and plasma cell leukemia.

Cell, rod
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides side vision and the ability to see objects in dim light (night vision).

Cell, stem
An ancestral cell, the most primitive type of cell.

Cell, T-4

Cell, totipotent
A cell with the capacity to form an entire organism.

Cells, germ
The eggs and sperm are the germ cells: the reproductive cells. Each mature germ cell is haploid in that it has a single set of 23 chromosomes containing half the usual amount of DNA and half the usual number of genes.

Cells, reproductive
The eggs and sperm are the reproductive cells. Each mature reproductive cell is haploid in that it has a single set of 23 chromosomes containing half the usual amount of DNA.

Cemento-ossifying fibroma
A hard fibrous growth that continues to enlarge, sometimes to very significant size, unless treated, most frequently seen in the jaw or mouth, sometimes in connection with a fracture or another type of injury. Treatment is by surgery.

Centenarian
Someone who is 100 or more years old. Someone 110 years old and over (no upper limit) may also be referred to as a supercentenarian.

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This dictionary contains 25007 terms.

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