| human normal immunoglobulin | A preparation of the proteins of liquid human plasma, containing the antibodies of normal adults; it is obtained from pooled liquid human plasma from a number of donors and may be prepared by precipitation with organic solvents under controlled conditions of pH, ionic strength, and temperature. Synonym: human normal immunoglobulin. (05 Mar 2000) |
|---|---|
| serum immunoglobulin electrophoresis | A test that detects and measures the various immunoglobulins in the blood. In the normal assay no monoclonal antibodies are detected. In multiple myeloma and chronic lymphocytic leukaemia a single clone of lymphocytes can produce one type of immunoglobulin that is detected in the electrophoresis as monoclonal (made by one cell clone). (27 Sep 1997) |
| immunoglobulin | <immunology> A specific protein substance that is produced by plasma cells to aid in fighting infection. Some immunoglobulins (gamma globulin) take part in various immune responses of the body to bacteria or foreign substances (allergens, tumour or transplanted tissue). Examples include IgG, IgM, IgA, IgD and IgE. (30 Mar 1998) |
| immunoglobulin A | <immunology> Major class of immunoglobulin of external secretions in mammals, also found in serum and body fluids such as tears and saliva and in the respiratory, reproductive, urinary and gastrointestinal tracts. Immunoglobulin A protects the bodys mucosal surfaces from infection and in secretions, it is found as a dimer (400 kD) joined by a short J chain and linked to a secretory portion or transport piece. In serum found as a monomer (170 kD). Immunoglobulin A is the main mechanism for providing local immunity against infections in the gut or respiratory tract and may act by reducing the binding between an immunoglobulin A coated micro organism and a host epithelial cell. Present in human colostrum but not transferred across the placenta. Have heavy chains. (30 Mar 1998) |
| immunoglobulin allotypes | Hereditary serologic types based on antigenic differences in the light and heavy chains of immunoglobulins due to allelic genes in the gene loci coding the chains. The inv system applies to the kappa light chains, the gm system applies to the heavy chains of IgG. (12 Dec 1998) |
| immunoglobulin class switching | Gene rearrangement of the b-lymphocyte which results in a substitution in the type of heavy-chain constant region that is expressed. This allows the effector response to change while the antigen binding specificity (variable region) remains the same. The majority of class switching occurs by a DNA recombination event but it also can take place at the level of RNA processing. (12 Dec 1998) |
| immunoglobulin constant region | That region of the immunoglobulin (antibody) molecule that is invariable in its amino acid sequence within any class of immunoglobulins. It confers the biological specificity to the ig and is grossly species specific. It comprises the c-terminus half of the light chains and three quarters or more of the heavy chains, all of the fc fragment, and the c-terminus half of the fab fragment. (12 Dec 1998) |
| immunoglobulin D | <immunology> This immunoglobulin (184 kD) is present at a low level (3-400 mcg/ml) but is a major immunoglobulin on the surface of B lymphocytes where it may play a role in antigen recognition. Its structure resembles that of immunoglobulin G but the heavy chains are of the delta type. (30 Mar 1998) |
| immunoglobulin domains | Structural units of immunoglobulin heavy or light chains that are composed of approximately 110 amino acids. Light chains of an immunoglobulin are composed of one constant domain and one variable domain. Heavy chains are composed of either three or four constant domains and one variable domain. (05 Mar 2000) |
| immunoglobulin E | <immunology> Class of immunoglobulin (188 kD) associated with immediate type hypersensitivity reactions and helminth infections. Present in very low amounts in serum and mostly bound to mast cells and basophils that have an immunoglobulin E specific Fc receptor (FceR). Immunoglobulin E has a high carbohydrate content and is also present in external secretions. Heavy chain of epsilon type. (30 Mar 1998) |
| immunoglobulin electrophoresis | <immunology, investigation> A test that detects and measures the various immunoglobulins in the blood. In the normal assay no monoclonal antibodies are detected but in multiple myeloma and chronic lymphocytic leukaemia a single clone of lymphocytes can produce one type of immunoglobulin that is detected in the electrophoresis as monoclonal (made by one cell clone). (30 Mar 1998) |
| immunoglobulin G | <immunology> The classical immunoglobulin class also called 7S IgG (150 kD). Composed of two identical light and two identical heavy chains, the constant region sequence of the heavy chains being of the type. The molecule can be described in another way as being composed of two Fab and an Fc fragment. The Fabs include the antigen combining sites, the Fc region consists of the remaining constant sequence domains of the heavy chains and contains cell binding and complement binding sites. Immunoglobulin Gs act on pathogens by agglutinating them, by opsonising them, by activating complement mediated reactions against cellular pathogens and by neutralising toxins. They can pass across the placenta to the foetus as maternal antibodies, unlike other Ig classes. In humans four main subclasses are known, IgG2 differs from the rest in not being transferred across the placenta and IgG4 does not fix complement. Immunoglobulin G is present at 8-16 mg/ml in serum. Synonym: gamma globulin. (30 Mar 1998) |
| immunoglobulin gm allotypes | Hereditary allotypic markers associated with the heavy chain of IgG. (12 Dec 1998) |
| immunoglobulin G subclass deficiency | A rare inherited disorder in which there are reduced levels of one or more IgG subclasses resulting from defective heavy chain genes or an abnormality in the regulation of immunoglobulin isotype switching. (05 Mar 2000) |
| immunoglobulin idiotypes | Unique, genetically controlled determinants present on antibodies whose specificity is limited to a single group of proteins (e.g., another antibody molecule or an individual myeloma protein). The idiotype appears to represent the antigenicity of the antigen-binding site of the antibody and to be genetically codetermined with it. The idiotypic determinants have been precisely located to the variable regions of both immunoglobin polypeptide chains. (12 Dec 1998) |