FACTOID # 18: Alaska spends more money per capita on elementary and secondary education than any other state.
 
 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 > Major histocompatibility complex
Protein images comparing the MHC I (1hsa) and MHC II (1dlh) molecules. (more details...)
Protein images comparing the MHC I (1hsa) and MHC II (1dlh) molecules. (more details...)

The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. It is the most gene-dense region of the mammalian genome and plays an important role in the immune system, autoimmunity, and reproductive success. The proteins encoded by the MHC are expressed on the surface of cells in all jawed vertebrates, and display both self antigens (peptide fragments from the cell itself) and nonself antigens (e.g. fragments of invading microorganisms) to a type of white blood cell called a T cell that has the capacity to kill or co-ordinate the killing of pathogens, infected or malfunctioning cells. Image File history File links MHC_I_vs_MHC_II.png‎ File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Major histocompatibility complex ... Image File history File links MHC_I_vs_MHC_II.png‎ File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Major histocompatibility complex ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... A gene family is a set of genes defined by presumed homology, i. ... This article does not cite any references or sources. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... Autoimmunity is the failure of an organism to recognize its own constituent parts (down to the sub-molecular levels) as self, which results in an immune response against its own cells and tissues. ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Classes Placodermi Chondrichthyes Acanthodii Osteichthyes Gnathostomata is the group of vertebrates with jaws. ... An antigen is any molecule that is recognized by antibodies. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... White Blood Cells redirects here. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... A pathogen (literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ...

Contents

Classification

In humans, the 3.6-Mb (3 600 000 base pairs) MHC region on chromosome 6 contains 140 genes between flanking genetic markers MOG and COL11A2.[1] About half have known immunological functions (see human leukocyte antigen). The same markers in the marsupial Monodelphis domestica (gray short-tailed opossum) span 3.95 Mb and contain 114 genes, 87 shared with humans.[2] This article is about modern humans. ... Base pairs, of a DNA molecule. ... A genetic marker is a known DNA sequences (e. ... HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ... Binomial name (Wagner, 1842) The Gray Short-tailed Opossum (Monodelphis domestica) is a small member of the Didelphidae family of opossums. ... Genera Several; see text Opossum fur is quite soft. ...


Subgroups

The MHC region is divided into three subgroups called MHC class I, MHC class II, and MHC class III.

Name Function Expression
MHC class I Encodes heterodimeric peptide-binding proteins, as well as antigen-processing molecules such as TAP and Tapasin. All nucleated cells. MHC class I proteins contain an a chain & b2-micro-globulin b chain. They present antigen fragments to cytotoxic T-cells cells and will bind to CD8 on cytotoxic T-cells.
MHC class II Encodes heterodimeric peptide-binding proteins and proteins that modulate antigen loading onto MHC class II proteins in the lysosomal compartment such as MHC II DM, MHC II DQ, MHC II DR, and MHC II DP. On antigen-presenting cells MHC class II proteins contain a & b chains and they present antigen fragments to T-helper cells by binding to the CD4 receptor on the T-helper cells.
MHC class III region Encodes for other immune components, such as complement components (e.g., C2, C4, factor B) and some that encode cytokines (e.g., TNF-α) and also hsp. Variable (see below)

Class III has a very different function than do class I and class II, but it has a locus between the other two (on chromosome 6 in humans), so they are frequently discussed together. MHC class I molecules are cell surface proteins found on most cells of the body. ... Sucrose, or common table sugar, is composed of glucose and fructose. ... Transporter associated with antigen processing (TAP) is a member of the ATP-binding-cassette transporter family (ABC transporter). ... Tapasin is a MHC class I antigen processing molecule present in the lumen of the endoplasmic reticulum. ... CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. ... Lysosomes are organelles in animal cells that contain digestive enzymes (acid hydrolases) to digest macromolecules. ... HLA-DM is an intracellular protein involved in peptide presentation by MHC class II. It is encoded by the genes HLA-DMA and HLA-DMB. HLA-DM functions by promoting the dissociation of the CLIP peptide (a place holder peptide) from MHC class II, and stabilizes MHC class II allowing... HLA-DQ (DQ) is a cell surface type protein found on antigen presenting cells. ... HLA-DR is a major histocompatibility complex, MHC class II, cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21. ... HLA-DP is a protein/peptide-antigen receptor and graft-versus-host disease antigen that is composed of 2 subunits, DPα and DPβ. DPα and DPβ are encoded by two loci, HLA-DPA1 and HLA-DPB1, that are found in the MHC Class II (or HLA-D) region in the... An antigen presenting cell (APC) is a cell that displays foreign antigen complexed with MHC on its surface. ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... A T helper cell, or (or TH) cell, is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class II MHC molecules found on professional antigen-presenting cells (APCs). ... A complement protein attacking an invader. ... Complement component 2 is a protein involved in the complement system. ... Complement component 4 is a protein involved in the complement system. ... Cytokines are a category of less-widely-known signalling proteins and glycoproteins that, like hormones and neurotransmitters, are used extensively in cellular communication. ... In medicine, tumor necrosis factor alpha (TNFα, cachexin or cachectin) is an important cytokine involved in systemic inflammation and the acute phase response. ... Heat shock proteins (HSP) are a group of proteins whose expression is increased when the cells are exposed to elevated temperatures. ... Chromosome 6 is one of the 23 pairs of chromosomes in humans. ...


Responses

The MHC proteins act as "signposts" that display fragmented pieces of an antigen on the host cell's surface. These antigens may be self or nonself. If they are nonself, there are two ways by which the foreign protein can be processed and recognized as being "nonself". An antigen or immunogen is a molecule that stimulates an immune response. ...

  • If the host is a leukocyte, such as a monocyte or neutrophil, it may have engulfed the particle (be it bacterial, viral, or particulate matter), broken it apart using lysozymes, and displayed the fragments on Class II MHC molecules.
  • On the other hand, if a host cell was infected by a bacterium or virus, or was cancerous, it may have displayed the antigens on its surface with a Class I MHC molecule. In particular, cancerous cells and cells infected by a virus have a tendency to display unusual, nonself antigens on their surface. These nonself antigens, regardless of which type of MHC molecule they are displayed on, will initiate the specific immunity of the host's body.

It is important to note that cells constantly process endogenous proteins and present them within the context of MHC I. Immune effector cells are trained not to react to self peptides within MHC, and as such are able to recognize when foreign peptides are being presented during an infection/cancer. White Blood Cells redirects here. ... Monocyte A monocyte is a leukocyte, part of the human bodys immune system that protects against blood-borne pathogens and moves quickly (aprox. ... Neutrophil granulocytes (commonly referred to as neutrophils) are a class of white blood cells and are part of the immune system. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... This article is about biological infectious particles. ... For other uses, see Cancer (disambiguation). ... The combination of humoral immunity and cell-mediated immunity. ...


HLA genes

The best-known genes in the MHC region are the subset that encodes cell-surface antigen-presenting proteins. In humans, these genes are referred to as human leukocyte antigen (HLA) genes, although people often use the abbreviation MHC to refer to HLA gene products. To clarify the usage, some of the biomedical literature uses HLA to refer specifically to the HLA protein molecules and reserves MHC for the region of the genome that encodes for this molecule; however this convention is not consistently adhered to. HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ... HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ...


The most intensely-studied HLA genes are the nine so-called classical MHC genes: HLA-A, HLA-B, HLA-C, HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQB1, HLA-DRA, and HLA-DRB1. In humans, the MHC is divided into three regions: Class I, II, and III. The A, B, and C genes belong to MHC class I, whereas the six D genes belong to class II. HLA-B (major histocompatibility complex, class I, B) is a human gene that provides instructions for making a protein that plays a critical role in the immune system. ...


Besides being scrutinized by immunologists for its pivotal role in the immune system, the MHC has also attracted the attention of many evolutionary biologists, due to the high levels of allelic diversity found within many of its genes. Indeed, much theory has been devoted to explaining why this particular region of the genome harbors so much diversity, especially in light of its immunological importance. This article is about evolution in biology. ... An allele (pronounced , ) (from the Greek αλληλος, meaning each other) is one member of a pair or series of different forms of a gene. ...


Molecular biology of MHC proteins

The classical MHC molecules (also referred to as HLA molecules in humans) have a vital role in the complex immunological dialogue that must occur between T cells and other cells of the body. At maturity, MHC molecules are anchored in the cell membrane, where they display short polypeptides to T cells, via the T cell receptors (TCRs). The polypeptides may be "self," that is, originating from a protein created by the organism itself, or they may be foreign ("nonself"), originating from bacteria, viruses, pollen, etc. The overarching design of the MHC-TCR interaction is that T cells should ignore self peptides while reacting appropriately to the foreign peptides. T cells are a subset of lymphocytes that play a large role in the immune response. ... Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ...


The immune system has another and equally important method for identifying an antigen: B cells with their membrane-bound antibodies, also known as B cell receptors (BCRs). However, whereas the BCRs of B cells can bind to antigens without much outside help, the TCRs of T cells require "presentation" of the antigen: this is the job of MHC. It is important to realize that, during the vast majority of the time, MHC are kept busy presenting self-peptides, which the T cells should appropriately ignore. A full-force immune response usually requires the activation of B cells via BCRs and T cells via the MHC-TCR interaction. This duplicity creates a system of "checks and balances" and underscores the immune system's potential for running amok and causing harm to the body (see autoimmune disorders). B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ...


All MHC molecules receive polypeptides from inside the cells they are part of and display them on the cell's exterior surface for recognition by T cells. However, there are major differences between MHC class I and MHC class II in the method and outcome of peptide presentation. T cells are a subset of lymphocytes that play a large role in the immune response. ... MHC class I molecules are cell surface proteins found on most cells of the body. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. ...


MHC evolution and allelic diversity

MHC gene families are found in essentially all vertebrates, though the gene composition and genomic arrangement vary widely. Chickens, for instance, have one of the smallest known MHC regions (19 genes), though most mammals have an MHC structure and composition fairly similar to that of humans. Gene duplication is almost certainly responsible for much of the genetic diversity. In humans, the MHC is littered with many pseudogenes. This article does not cite any references or sources. ... This article or section does not adequately cite its references or sources. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria For the folk-rock band see The Mammals. ... Schematic of a region of a chromosome before and after a duplication event Gene duplication occurs when an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome leads to the duplication of a region of DNA containing a gene [1]. The significance of this process for... A pseudogene is a nucleotide sequences that is similar to a normal gene, but is not expressed as a functional protein. ...


One of the most striking features of the MHC, particularly in humans, is the astounding allelic diversity found therein, and especially among the nine classical genes. In humans, the most conspicuously-diverse loci, HLA-A, HLA-B, and HLA-DRB1, have roughly 250, 500, and 300 known alleles respectively -- diversity truly exceptional in the human genome. The MHC gene is the most polymorphic in the genome. Population surveys of the other classical loci routinely find tens to a hundred alleles -- still highly diverse. Many of these alleles are quite ancient: it is often the case that an allele from a particular HLA gene is more closely related to an allele found in chimpanzees than it is to another human allele from the same gene. The gene pool of a species or a population is the complete set of unique alleles that would be found by inspecting the genetic material of every living member of that species or population. ...


Phylogenetically the marsupial MHC lies between eutherian mammals and the minimal essential MHC of birds, although it is closer in organization to non-mammals. Its Class I genes have amplified within the Class II region, resulting in a unique Class I/II region.[2]


The allelic diversity of MHC genes has created fertile grounds for evolutionary biologists. The most important task for theoreticians is to explain the evolutionary forces that have created and maintained such diversity. Most explanations invoke balancing selection (see polymorphism (biology)), a broad term that identifies any kind of natural selection in which no single allele is absolutely most fit. Frequency-dependent selection and heterozygote advantage are two types of balancing selection that have been suggested to explain MHC allelic diversity. However, recent models suggest that a high number of alleles is not plausibly achievable through heterozygote advantage alone. Pathogenic co-evolution, a counter-hypothesis has recently emerged; it theorizes that the most common alleles will be placed under the greatest pathogenic pressure, thus there will always be a tendency for the least common alleles to be positively selected for. This creates a "moving target" for pathogen evolution. As the pathogenic pressure decreases on the previously common alleles, their concentrations in the population will stabilize, and they will usually not go extinct if the population is large enough, and a large number of alleles will remain in the population as a whole. This explains the high degree of MHC polymorphism found in the population, although an individual can have a maximum of 18 MHC I or II alleles. Sickle-shaped red blood cells Balancing selection refers to forms of natural selection which work to maintain genetic polymorphisms (or multiple alleles) within a population. ... In biology, polymorphism can be defined as the occurrence in the same habitat of two or more forms of a trait in such frequencies that the rarer cannot be maintained by recurrent mutation alone. ... For other uses, see Natural selection (disambiguation). ... Frequency dependent selection is the term given to an evolutionary process where the fitness of a phenotype is dependent on the relative frequency of other phenotypes in a given population. ... A heterozygote advantage (heterozygous advantage or overdominance) describes the case in which the heterozygote genotype has a higher relative fitness than either the homozygote dominant or homozygote recessive genotype. ...


MHC and sexual selection

It has been suggested that MHC plays a role in the selection of potential mates, via olfaction. MHC genes make molecules that enable the immune system to recognise invaders; generally, the more diverse the MHC genes of the parents, the stronger the immune system of the offspring. It would obviously be beneficial, therefore, to have evolved systems of recognizing individuals with different MHC genes and preferentially selecting them to breed with. Image File history File links Mergefrom. ... Claus Wedekind is a Swiss biological researcher famous for his 1995 study that determined a major histocompatibility complex dependent mate preference in humans. ... Olfaction (also known as olfactics) refers to the sense of smell. ...


Yamazaki et al. (1976) showed this to be the case for male mice, who show such a preference for females of different MHC. Similar results have been obtained with fish.[3]


In 1995, Swiss biologist Claus Wedekind determined MHC-dissimilar mate selection tendencies in humans. In the experiment, a group of female college students smelled t-shirts that had been worn by male students for two nights, without deodorant, cologne or scented soaps. Overwhelmingly, the women preferred the odors of men with dissimilar MHCs to their own. However, their preference was reversed if they were taking oral contraceptives.[4] The hypothesis is that MHCs affect mate choice and that oral contraceptives can interfere with this. A study in 2005 on 58 test subjects showed similar results.[5] Claus Wedekind is a Swiss biological researcher famous for his 1995 study that determined a major histocompatibility complex dependent mate preference in humans. ...


References

  1. ^ MHC Sequencing Consortium (1999). "Complete sequence and gene map of a human major histocompatibility complex". Nature 401: 921–923. 
  2. ^ a b Belov, Katherine; Janine E. Deakin, Anthony T. Papenfuss, et. al (March 2006). "Reconstructing an Ancestral Mammalian Immune Supercomplex from a Marsupial Major Histocompatibility Complex". PLoS Biol 4(3) (e46). 
  3. ^ Boehm T, Zufall F. "MHC peptides and the sensory evaluation of genotype." Trends Neurosci. 2006 Feb;29(2):100-7. PMID 16337283
  4. ^ Wedekind, C.; Seebeck, T., Bettens, F. and Paepke, A. J. (1995). "MHC-dependent mate preferences in humans". Proc Biol Sci 260 (1359): 245-249. PMID 7630893. 
  5. ^ Santos PS, Schinemann JA, Gabardo J, Bicalho Mda G. "New evidence that the MHC influences odor perception in humans: a study with 58 Southern Brazilian students." Horm Behav. 2005 Apr;47(4):384-8. PMID 15777804

Additional images

See also

Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages and NK-cells, the production of antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. ... Disassortative sexual selection is a form of sexual selection in which one sex chooses the other, in such a way that the offspring benefits from the diversity of the parental genotypes. ... Humoral immunity is the aspect of immunity that is mediated by secreted antibodies, produced in the cells of the B lymphocyte lineage (B cell). ... Transplant rejection occurs when the immune system of the recipient of a transplant attacks the transplanted organ or tissue. ...

External links

Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. ... The immune system is the collection of organs and tissues involved in the adaptive defense of a body against foreign biological material. ... The innate immune system comprises the cells and mechanisms that defend the host from infection by other organisms, in a non-specific manner. ... Humoral immunity is the aspect of immunity that is mediated by secreted antibodies, produced in the cells of the B lymphocyte lineage (B cell). ... Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages and NK-cells, the production of antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. ... A complement protein attacking an invader. ... Anaphylatoxins, or anaphylotoxins, are fragments (C3a, C4a or C5a) that are produced during the pathways of the complement system. ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ... // Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell and are all clones of a single parent cell. ... Polyclonal antibodies are antibodies that are derived from different B-cell lines. ... An autoantibody is an antibody (a type of protein) manufactured by the immune system that is directed against one or more of the individuals own proteins. ... The allotype affects the constant region (labeled CL and CH1-3 in the diagram. ... In immunology, the immunoglobulin isotype refers to the type of chain. ... The idiotype affects the variable region (labeled VL and VH in the diagram. ... An antigen or immunogen is a molecule that stimulates an immune response. ... SEB, A typical bacterial superantigen (PDB:3SEB) The β-grasp domain is shown in red, and the β-barrel in green: The disulphide loop is shown in yellow SEC3 (yellow) complexed with an MHC-II molecule (green & cyan): The SAgs binds adjacent to the antigen (purple) presentation cleft in the MHC-II... White Blood Cells redirects here. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Natural killer cells (NK) are a type of lymphocyte (a white blood cell) and a component of nonspecific immune defense. ... Mast cells A mast cell (or mastocyte) is a resident cell of areolar connective tissue (loose connective tissue) that contains many granules rich in histamine and heparin. ... Categories: Wikipedia cleanup | Biology stubs | Blood and immune system cells ... Eosinophils are white blood cells that are responsible for combating infection by parasites in the body. ... A phagocyte is a cell that ingests and destroys foreign matter such as microorganisms or debris via a process known as phagocytosis. ... Neutrophil granulocytes (commonly referred to as neutrophils) are a class of white blood cells and are part of the immune system. ... A macrophage of a mouse stretching its arms to engulf two particles, possibly pathogens Macrophages (Greek: big eaters, from makros large + phagein eat) are cells within the tissues that originate from specific white blood cells called monocytes. ... Dendritic cells (DC) are immune cells and form part of the mammal immune system. ... An antigen-presenting cell (APC) is a cell that displays foreign antigen complexed with MHC on its surface. ... The reticuloendothelial system (RES), part of the immune system, consists of the phagocytic cells located in reticular connective tissue, primarily monocytes and macrophages. ... Immunity is a medical term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. ... Autoimmunity is the failure of an organism to recognize its own constituent parts (down to the sub-molecular levels) as self, which results in an immune response against its own cells and tissues. ... Allergy is an abnormal reaction to a substance foreign to the body that is acquired, predictable and rapid. ... Immune or immunological tolerance is the process by which the immune system does not attack an antigen. ... Central tolerance is a condition caused by tumor cells caused by tumor antigens inhibiting the immune system which has no reaction. ... In medicine, immunodeficiency (or immune deficiency) is a state in which the immune systems ability to fight infectious disease is compromised or entirely absent. ... Immunogenetics is the branch of medical research that explores the relationship between the immune system and genetics. ... This article needs to be cleaned up to conform to a higher standard of quality. ... V(D)J recombination is a mechanism of DNA recombination used by humans and other vertebrates for immunological protection against attacks by bacterial, viral, and parasitic invaders. ... Immunoglobulin class switching (or isotype switching) is a mechanism by which the constant region of a heavy chain changes. ... HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ... Cytokines are a category of less-widely-known signalling proteins and glycoproteins that, like hormones and neurotransmitters, are used extensively in cellular communication. ... An opsonin is any molecule that acts as a binding enhancer for the process of phagocytosis, for example, by coating the negatively-charged molecules on the membrane. ... Cytolysin refers to the substance or antibody elaborated by microorganisms, plants or animals that is specifically toxic to individual cells [1], in many cases causing their dissolution through lysis. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ... An epitope is the part of a macromolecule that is recognized by the immune system, specifically by antibodies, B cells, or cytotoxic T cells. ... A hapten is a small molecule which can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one which also does not elicit an immune response by itself. ... Cross-reactivity is the reaction between an antigen and an antibody that was generated against a different but similar antigen. ... An antigen or immunogen is a molecule that stimulates an immune response. ... This article or section does not adequately cite its references or sources. ... HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ... MHC class I molecules are cell surface proteins found on most cells of the body. ... HLA-A belongs to the MHC (human leukocyte antigen= HLA) class I heavy chain receptors. ... HLA-B (major histocompatibility complex, class I, B) is a human gene that provides instructions for making a protein that plays a critical role in the immune system. ... HLA-C belongs to the MHC (human = HLA) class I heavy chain receptors. ... HLA-E is one of a family of molecules known as MHC class 1B. It has a very specialized role in cell recognition by NK cells (Natural Killer). ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. ... HLA-DP is a protein/peptide-antigen receptor and graft-versus-host disease antigen that is composed of 2 subunits, DPα and DPβ. DPα and DPβ are encoded by two loci, HLA-DPA1 and HLA-DPB1, that are found in the MHC Class II (or HLA-D) region in the... HLA DQ is a protein/peptide-antigen receptor and graft-versus-host disease antigen that is composed of 2 subunits DQα and DQβ. DQα and DQβ are encoded by two loci, HLA-DQA1 and HLA-DQB1 which are found in the MHC Class II (or HLA-D) region in the... HLA-DR is a major histocompatibility complex, class II, cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21. ... Minor histocompatibility antigen is a histocompatibility antigen which is occasionally an obstacle in suppressing an immune response,[1], though less frequently than those of the major histocompatibility complex. ... This article or section does not cite any references or sources. ... There are very few or no other articles that link to this one. ... The International Society of Blood Transfusion (ISBT) currently recognises 29 major blood group systems (including the ABO and Rh systems). ... Cell Adhesion Molecules (CAMs) are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix (ECM) in the process called cell adhesion. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Antigen presentation stimulates T cells to become either cytotoxic CD8+ cells or helper CD4+ cells. ... Antigen presentation stimulates T cells to become either cytotoxic CD8+ cells or helper CD4+ cells. ... The T-cell receptor complex with TCR-α and TCR-β chains, CD3 and ζ-chain accessory molecules and the co-receptor CD4 In immunology, the CD3 antigen (CD stands for cluster of differentiation) is a protein complex composed of four distinct chains (CD3γ, CD3δ and two times CD3ε) in mammals, that associate... CD3 or CD-3 may be: CD3 receptor Ford CD3 platform MediaMax CD-3, copy protection scheme MiniCD, a 3-inch CD CD3, Color Developing Agent 3, the color developer for E6 process Category: ... CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ... CD8 (cluster of differentiation 8) is a transmembrane glycoprotein which serves as a co-receptor for the T cell receptor (TCR). ... CD8 (cluster of differentiation 8) is a transmembrane glycoprotein which serves as a co-receptor for the T cell receptor (TCR). ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... MHC class I molecules are cell surface proteins found on most cells of the body. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. ...

 
 

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