FACTOID # 24: Looking for table makers? Head to Mississippi, with an overwhlemingly large number of employees in furniture manufacturing.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Cluster of differentiation


The CD cell surface molecules are recognized by specific sets of antibodies. Cells are the fundamental unit of life and an extraordinary array of specialized cells have evolved to accomplish the many different tasks required of organisms in their environments. ... Schematic of antibody binding to an antigen An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ...


Cells are the fundamental unit of life and an extraordinary array of specialized cells have evolved to accomplish the many different tasks required of organisms in their environments. In order for specialized cells to interact with each other and their environments, they must bring things in, release other things, sense pressure, and, in some cases, recognize other cells and present markers that allow other cells to recognize them. All of these functions require cells to have lots of unique moleculess on their surfaces. In fact, imagine a pin cushion with thousands and thousands of pins. Some are big, some are small. Some are green, some are blue. Some are sticky. Some have flat heads, some have round heads, some are pushed all the way in, some are sticking way out. Some of the pins are needles, little pipes, channels that let things into and out of the cell. Cluster of differentiation (CD) molecules are one kind of cell surface molecule. They are found on the surfaces of various cells and can be recognized by specific sets of antibodies. These antibodies can be used to identify the cell type, stage of differentiation and activity of a cell. Unlike many of the descriptive words used for biological molecules, like transporters, receptors, the CD nomenclature was developed empirically by immunology researchers. To understand the CD nomenclature, one should first learn about a bit about antibodies. In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... Schematic of antibody binding to an antigen An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... Embryonic stem cells differentiate into cells in various body organs. ... Wikipedia does not yet have an article with this exact name. ...

Contents


Nomenclature

The CD nomenclature was proposed and established in the 1st International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), which was held in Paris in 1982. This system was intended for the classification of the many monoclonal antibodies (mAbs), generated by different laboratories around the world, against various cell surface molecules (antigens) on leukocytes (white blood cells). Since then, the use has expanded to many other cell types, and more than 250 CD clusters and subclusters have been identified. The HLDA workshops assign each CD based on the same reactivity to one human antigen by at least two mAbs; the provisional indicator "w" (as in "CDw186") is sometimes given to a cluster not well characterized or represented by only one mAb. The Eiffel Tower has become the symbol of Paris throughout the world. ... 1982 (MCMLXXXII) was a common year starting on Friday of the Gregorian calendar. ... Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell, all clones of a single parent cell. ... Cells are the fundamental unit of life and an extraordinary array of specialized cells have evolved to accomplish the many different tasks required of organisms in their environments. ... An antigen is a substance that stimulates an immune response, especially the production of antibodies. ... White blood cells (a. ...


Uses

  • CD molecules are often referred to when sorting cells by flow cytometry. A '+' or a '–' symbol is used to indicate if a certain fraction of cells possesses or lacks a CD molecule; for example, a "CD34+, CD31–" cell is one that expresses CD34, but not CD31. This would typically correspond to a stem cell, rather than a fully differentiated endothelial cell.
  • The most commonly referred to CD molecules are CD4 and CD8, which are markers for two different subtypes of T-lymphocytes, for the most part (dendritic cells also express CD8). CD4 is specifically recognized and bound by HIV, leading to viral infection and destruction of CD4+ T cells. The relative abundance of CD4+ and CD8+ T cells is often used to monitor the progression of an HIV infection.
  • CD molecules are not merely markers on the cell surface. Not every CD molecule has been thoroughly characterised, but most of them bring important features to the cells that carry them. In the example of CD4 & CD8, these molecules are critical in the antigen recognition pathway.

Flow cytometry is a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... Dendritic cells (DC) are immune cells and form part of the mammal immune system. ... Human immunodeficiency virus (commonly known as HIV, and formerly known as HTLV-III and lymphadenopathy-associated virus) is a retrovirus that primarily infects vital components of the human immune system such as CD4+ T cells, macrophages and dendritic cells. ...

See also

This list includes Cluster of Differentiation or CD molecules. ...

External links

  • A list of CD molecules, at ebioscience.com
  • Another list of CD molecules, at Expasy.org
  • Another list of CD molecules, at Sciencegateway.org
  • Yet another list of CD molecules, at PathologyOutlines.com
  • Catalogue of some CD-factors, as R&D Systems.

  Results from FactBites:
 
Cluster of differentiation - Wikipedia, the free encyclopedia (652 words)
Cluster of differentiation (CD) molecules are one kind of cell surface molecule.
These antibodies can be used to identify the cell type, stage of differentiation and activity of a cell.
The CD nomenclature was proposed and established in the 1st International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), which was held in Paris in 1982.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m