|
Major Histocompatibility Complex, Class II, DQ Alpha 1
Major histocompatibility complex, class II, DQ alpha 1, also known as HLA-DQA1, is a human gene present on short arm of chromosome 6 (6p21.3) and also denotes the genetic locus which contains this gene. The protein encoded by this gene is one of two proteins that are required to form the DQ heterodimer, a cell surface receptor essential to the function of the immune system. Function HLA-DQA1 belongs to the HLA class II alpha chain paralogues. This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages). Gene structure and polymorphisms The alpha chain contains 5 exons. Exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular protein domains, exon 4 encodes the transmembrane doma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphism (biology)
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major Histocompatibility Complex
The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules. This locus got its name because it was discovered via the study of transplanted tissue compatibility. Later studies revealed that tissue rejection due to incompatibility is only a facet of the full function of MHC molecules: binding an antigen derived from self-proteins, or from pathogens, and bringing the antigen presentation to the cell surface for recognition by the appropriate T-cells. MHC molecules mediate the interactions of leukocytes, also called white blood cells (WBCs), with other leukocytes or with body cells. The MHC determines donor compatibility for organ transplant, as well as one's susceptibility to autoimmune diseases. In a cell, protein molecules of the host's own phenotype or of other biologic entities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ4
HLA-DQ4 (DQ4) is a serotype subgroup within HLA-DQ(DQ) serotypes. The serotype is determined by the antibody recognition of β4 subset of DQ β-chains. The β-chain of DQ is encoded by HLA-DQB1 locus and DQ4 are encoded by the HLA-DQB1 allele group. This group currently contains 2 common alleles, DQB1 and DQB1. HLA-DQ4 and HLA-DQB1*04 are almost synonymous in meaning. DQ4 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. These isoforms, nicknamed DQ4.3 and DQ4.4, are also encoded by the DQA1 and DQA1 genes, respectively. Serotype Alleles DQB1*0401 DQB1*0402 Haplotypes DQ4.3 DQA1*0303:DQB1*0401 is linked to DRB1*0405 and is common on the west Pacific rim, from Indonesia to Japan and inland areas of Eastern Asia. In Japan it confers susceptibility to juvenile diabetes likely via the DR4 gene. DQA1*0303:DQB1*0402 is primarily found in Northeastern Asia and the west Pacific rim. It is similar to DQA1*03 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ7
HLA-DQ7 (DQ7) is an HLA- DQ serotype that recognizes the common HLA DQB1*0301 and the less common HLA DQB1*0304 gene products. DQ7 is a form of 'split antigen' of the broad antigen group DQ3 which also contains DQ8 and DQ9. DQ7 is linked by haplotype to a number of DQA1 (DQ alpha chain) genes, producing in cis-haplotype form, a large number of DQ αβ isoforms. These DQ alpha chains are also known to form transhaplotype isomers with other HLA-DQ. DQ7 is linked to the following alpha chains genes (DQA1*) * 03 – *0301, *0302, *0303 * 0401 * 0505 * 0601 Serology Serotyping efficiency. The serotyping efficiency of DQ7 toward DQB1*0301 is reasonably good, but still results in some false negatives, for *0304 the typing efficiency is poor and cross-reaction with DQ8 is relatively high. Alleles DQB1*0301 DQB1*0301 is the major DQ7 allele DQB1*0301 appears to be associated with lupus anticoagulant. DQB1*0304 DQB1*0304 is the minor DQ7 allele Haplotypes DQ haplotypes of this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ8
HLA-DQ8 (DQ8) is a human leukocyte antigen serotype within the HLA-DQ (DQ) serotype group. DQ8 is a split antigen of the DQ3 broad antigen. DQ8 is determined by the antibody recognition of β8 and this generally detects the gene product of DQB1 *0302. DQ8 is commonly linked to autoimmune disease in the human population. DQ8 is the second most predominant isoform linked to coeliac disease and the DQ most linked to Type 1 Diabetes. DQ8 increases the risk for rheumatoid arthritis and is linked to the primary risk locus for RA, HLA-DR4. DR4 also plays an important role in Type 1 Diabetes. While the DQ8.1 haplotype is associated with disease, there is no known association with the DQB1*0305, DQ8.4 or DQ8.5 haplotypes (see infobox) with autoimmune disease; however, this may be the result of lack of study in populations that carry these and the very low frequency. DQ8.1 also differs from other HLA in population frequencies. Typically for MHC Class II antigens in humans, haplotype fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ9
HLA-DQ9 (DQ9) is a human leukocyte antigen serotype within the HLA-DQ (DQ) serotype group. DQ9 is a split antigen of the DQ3 broad antigen. DQ9 is determined by the antibody recognition of β9 and this generally detects the gene product of DQB1 *0303. Serology The serotyping efficiency of DQ9 is poor. The recognition of DQB1*0303 by DQ9 and or DQ3 is poorest, DQ2 which recognizes a different DQB1 subgroup recognizes DQB1*0303 as efficiently as DQ3. For this reason DQ9 serotyping is a poor method of typing for transplantation or disease association prediction or study. DQB1*0303 (DQ9) is associated with nasal polyps, gestational diabetes, microscopic polyangiitis (Japanese). Primary linkage is with DRB1*0901-DQB1*0303 Haplotypes and disease DQ9.2 DQA1*0201:DQB1*0303 is associated with type I psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ2
HLA-DQ3 (DQ3) is a serotype group within HLA-DQ (DQ) serotyping system. The serotype is determined by the antibody recognition of β2 subset of DQ β-chains. The β-chain of DQ is encoded by HLA-DQB1 locus and DQ2 are encoded by the HLA-DQB1 allele group. This group currently contains two common alleles, DQB1 and DQB1. HLA-DQ2 and HLA-DQB1*02 are almost synonymous in meaning. DQ2 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. These isoforms, nicknamed DQ2.2 and DQ2.5, are also encoded by the DQA1 and DQA1 genes, respectively. DQ2 is most common in Western Europe, North Africa and East Africa. Highest frequencies are observed in parts of Spain and Ireland; this distribution correlates with the frequency of two of the most prevalent autoimmune diseases. There is also an increase in DQB1 in Central Asia, peaking in Kazakhstan and declining slowly west to east into China and finally Southeast Asia. DQA1 : DQB1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ1
HLA-DQ1 is a serotype that covers a broad range of HLA-DQ haplotypes. Historically it was identified as a DR-like alpha chain called DC1; later, it was among 3 types DQw1 (later DQ1, and split into DQ5 and DQ6), DQw2 and DQw3. Of these three serotyping specificities only DQw1 recognized DQ alpha chain. The serotype is positive in individuals who bear the DQA1*01 alleles. The most frequently found within this group are: DQA1*0101, *0102, *0103, and *0104. In the illustration on the right, DQ1 serotyping antibodies recognizes the DQ α (magenta), where antibodies to DQA1* gene products bind variable regions close to the peptide binding pocket. Serotypes The serotyping efficiency of DQ1 recognition relative to DQ5 and DQ6 is listed below. Since DQ1 recognizes alpha, the DQ5 and DQ6 recognition are to beta chain. Meaning that DQ1 is corecognized with DQ5 and DQ6. The table to the left shows some of the serotyping efficiencies. Efficient recognition of a genotyped allele approa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ6
HLA-DQ6 (DQ6) is a human leukocyte antigen serotype within HLA-DQ (DQ) serotype group. The serotype is determined by the antibody recognition of β6 subset of DQ β-chains. The β-chain of DQ isoforms are encoded by HLA-DQB1 locus and DQ6 are encoded by the HLA-DQB1 allele group. This group currently contains many common alleles, DQB1 is the most common. HLA-DQ6 and DQB1 are almost synonymous in meaning. DQ6 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. For DQ6, however, cis-isoform pairing only occurs with DQ1 α-chains. There are many haplotypes of DQ6. Serology Alleles DQB1*0601 DQB1*0601 is generally linked to DQA1*0103 as 6.1 haplotype. This haplotype is more common in Japan and other parts of East Asia. DQB1*0602 DQB1*0602 is commonly linked to DQA1*0102 to form 6.2 haplotype. DQ6.2 and is common from Central Asia into Western Europe, *0602 is also linked to DQA1*0103 in parts of Asia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DQ5
HLA-DQ5 (DQ5) is a human leukocyte antigen serotype subgroup within HLA-DQ(DQ) serotypes. The serotype is determined by the antibody recognition of β5.x subset of DQ β-chains. The β-chain of DQ is encoded by HLA-DQB1 locus and DQ5 are encoded by the HLA-DQB1 allele group. This group currently contains 4 common alleles, DQB1, , , and . HLA-DQ5 and HLA-DQB1*05 are almost synonymous in meaning. DQ5 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. These isoforms, are all HLA-DQ1 encoded by the DQA1 allele group. Serology The efficiency of DQ1 recognition relative to DQ5 and DQ6 is listed above. Since DQ1 recognizes alpha, the DQ5 and DQ6 recognition are to beta chain. Meaning that DQ1 is corecognized with DQ5 and DQ6. Efficient recognition of a genotyped allele approaches 100%. Compared to DQ2 serotyping of DQB1*0201 positive individuals (98%), the efficiency of DQ5 recognition is relatively low and error pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoietic Stem Cell Transplantation
Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce additional normal blood cells. It may be autologous (the patient's own stem cells are used), allogeneic (the stem cells come from a donor) or syngeneic (from an identical twin). It is most often performed for patients with certain cancers of the blood or bone marrow, such as multiple myeloma or leukemia. In these cases, the recipient's immune system is usually destroyed with radiation or chemotherapy before the transplantation. Infection and graft-versus-host disease are major complications of allogeneic HSCT. HSCT remains a dangerous procedure with many possible complications; it is reserved for patients with life-threatening diseases. As survival following the procedure has increased, its use has expanded beyond cancer to autoimmun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
