Immunoglobulin M

Last updated
Immunoglobulin M
(pentamer)
IgM scheme.svg
Protein type antibody
Subunit nameGeneChromosomal locus
Immunoglobulin heavy chain μ IGH@

Immunoglobulin M (IgM) is the largest of several isotypes of antibodies (also known as immunoglobulin) that are produced by vertebrates. IgM is the first antibody to appear in the response to initial exposure to an antigen; [1] [2] causing it to also be called an acute phase antibody. In humans and other mammals that have been studied, plasmablasts in the spleen are the main source of specific IgM production. [3] [4]

Contents

History

In 1937, an antibody was observed in horses hyper-immunized with pneumococcus polysaccharide that was much larger in size than the typical rabbit γ-globulin, [5] with a molecular weight of 990,000 daltons. [6] In accordance with its larger size, the new antibody was originally referred to as γ-macroglobulin, and subsequently termed IgM—M for “macro”. The V domains of normal immunoglobulin are highly heterogeneous, reflecting their role in protecting against the great variety of infectious microbes, and this heterogeneity impeded detailed structural analysis of IgM. Two sources of homogeneous IgM were subsequently discovered. First, the high molecular weight protein produced by some multiple myeloma patients was recognized to be a tumor-produced γ-macroglobulin, and because the tumor is a clone, the IgM it produces is homogeneous. [7] In the 1960s, methods were developed for inducing immunoglobulin-producing tumors (plasmacytomas) in mice, thus providing a source of homogeneous immunoglobulins of various isotypes, including IgM (reviewed in [8] ). More recently, the expression of engineered immunoglobulin genes in tissue culture can be used to produce IgM with specific alterations and thus to identify the molecular requirements for features of interest.[ citation needed ]

Structure

Immunoglobulins are composed of light chains and heavy chains. The light chain (λ or κ) is a protein of ~220 amino acids, composed of a variable domain, VL (a segment of approximately 110 amino acids), and a constant domain, CL (also approximately 110 amino acids long). The μ heavy chain of IgM is a protein of ~576 amino acids, includes a variable domain (VH ~110 amino acids), four distinct constant region domains (Cμ1, Cμ2, Cμ3, Cμ4, each ~110 amino acids) and a "tailpiece" of ~20 amino acids. The μ heavy chain bears oligosaccharides at five asparagine residues. The oligosaccharides on mouse and human IgM have been partially characterized by a variety of techniques, including NMR, lectin binding, various chromatographic systems, and enzymatic sensitivity (reviewed in [9] ). The structure of the oligosaccharides at each site varies in detail, and the predominant oligosaccharides—biantennary, triantennary, and high mannose—differ among the sites.[ citation needed ]

Figure 1. Schematic model of IgM A) The mL heterodimer, sometimes called a halfmer, with variable (VH, VL) and constant region (Cm1, Cm2, Cm3, Cm4tp; CL) domains. The cysteines that mediate disulfide bonds between m chains are shown as red arrowheads, so that a cysteine disulfide bond appears as a red double arrowhead (red diamond). B) The IgM "monomer" (mL)2. The disulfide bonds between Cm2 domains are represented by a red double arrowhead. C, D) Two models for J chain-containing IgM pentamer that have appeared in various publications at various times. As in (B), the disulfide bonds between Cm2 domains and the disulfide bonds between Cm4tp domains are represented by a red double arrowhead; the Cm3 disulfide bonds are represented (for clarity) by long double-headed arrows. The connectivity, i.e., the inter-chain disulfide bonding of the m chains, is denoted like electrical connectivity. In (C) the Cm3 disulfide bonds join m chains in parallel with the Cm4tp disulfide bonds, and these disulfide bonds join m chains in series with the Cm2 disulfide bonds. In (D) the Cm2 and Cm4tp disulfide bonds join m chains in parallel and both types join m chains in series with the Cm3 disulfide bonds. (Figure reproduced with permission of the publisher and authors ). Schematic model of IgM.jpg
Figure 1. Schematic model of IgM
A) The μL heterodimer, sometimes called a halfmer, with variable (VH, VL) and constant region (Cμ1, Cμ2, Cμ3, Cμ4tp; CL) domains. The cysteines that mediate disulfide bonds between μ chains are shown as red arrowheads, so that a cysteine disulfide bond appears as a red double arrowhead (red diamond).
B) The IgM “monomer” (μL)2. The disulfide bonds between Cμ2 domains are represented by a red double arrowhead.
C, D) Two models for J chain-containing IgM pentamer that have appeared in various publications at various times. As in (B), the disulfide bonds between Cμ2 domains and the disulfide bonds between Cμ4tp domains are represented by a red double arrowhead; the Cμ3 disulfide bonds are represented (for clarity) by long double-headed arrows. The connectivity, i.e., the inter-chain disulfide bonding of the μ chains, is denoted like electrical connectivity. In (C) the Cμ3 disulfide bonds join μ chains in parallel with the Cμ4tp disulfide bonds, and these disulfide bonds join μ chains in series with the Cμ2 disulfide bonds. In (D) the Cμ2 and Cμ4tp disulfide bonds join μ chains in parallel and both types join μ chains in series with the Cμ3 disulfide bonds. (Figure reproduced with permission of the publisher and authors ).

The multimeric structure of IgM is shown schematically in Figure 1. Figure 1A shows the "heterodimer" composed of one light chain, denoted L, and one heavy chain, denoted μ. The heavy and light chains are held together both by disulfide bonds (depicted as red triangles) and by non-covalent interactions.

Figure 1B shows two μL units linked by a disulfide bond in the Cμ2 domains; this (μL)2 structure is often referred to as the IgM "monomer", as it is analogous in some ways to the structure of immunoglobulin G (IgG).

On the basis of its sedimentation velocity and appearance in electron micrographs, it was inferred that IgM usually occurs as a "pentamer", i.e., a polymer composed of five “monomers” [(μL)2]5, and was originally depicted by the models in Figures 1C and 1D, with disulfide bonds between the Cμ3 domains and between the tail pieces. [11] [12] Also shown is that pentameric IgM includes a third protein, the J chain. J chain (J for joining) was discovered as a covalently bonded component of polymeric IgA and IgM. [13] [14] The J chain is a small (~137 amino acids), acidic protein. As shown, the J chain joins two μ chains via disulfide bonds involving cysteines in the tailpieces. [15]

Molecular requirements for forming polymeric IgM

It was initially expected that the J chain would be important for forming the polymeric immunoglobulins, and indeed polymerization of IgA depends strongly (but not absolutely) on the J chain. [16] [17] In contrast, polymeric IgM forms efficiently in the absence of the J chain. [18] [19]

The predominant form of human and mouse IgM is the pentamer. By way of comparison, the structure of IgM from frogs (Xenopus) is predominantly hexameric, [20] [21] IgM from bony fish is predominantly tetrameric, and IgM from cartilaginous fish (mainly sharks) is predominantly pentameric. [22] [23] Although the pentameric form predominates in mice and humans, the hexameric form has also been observed. [24] [25] Subsequent studies using recombinant DNA expression systems indicated that a hexamer is a major form of mouse IgM when the IgM is produced under conditions where the incorporation of the J chain is prevented, either by producing IgM in cells that lack the J chain [18] or by producing IgM with a μ heavy chain that lacks the cysteine in the tailpiece. [26] [27] In summary, hexameric IgM never contains the J chain; pentameric IgM can be formed so as to include or not include the J chain. [28]

An important difference between the μ and γ heavy chains is the availability of cysteines for forming disulfide bonds between heavy chains. In the case of the γ heavy chain, the only inter-γ bonds are formed by cysteines in the hinge, and accordingly, each γ chain binds to only one other γ chain. By contrast, the Cμ2 and Cμ3 domains and the tailpiece each include a cysteine that form a disulfide bond with another μ chain. The cysteines in the Cμ2 domains mediate the formation of monomeric IgM (μL)2. The tailpiece along with the included cysteine is necessary and sufficient for the formation of polymeric immunoglobulins. That is, deleting the tailpiece from the μ heavy chain prevents the formation of polymeric IgM. [29] Conversely, cells expressing a γ heavy chain that has been modified to include the tailpiece produce polymeric IgG. [30] [31] [32]

The role of the cysteine in the Cμ3 domain is more subtle. Figures 1C and 1D represent possible models for pentameric IgM. In these models, each μ chain is envisaged to bind two other μ chains. However, neither model alone can fully account for the structure of polymeric IgM. For example, the model in Figure 1C predicts that the disulfide bond between the Cμ2 domains is essential for making disulfide-bonded polymeric IgM. The model in Figure 1D predicts that the disulfide bond between the Cμ3 domains is essential. Disulfide bonded, polymeric, IgM can still be made if any one of the three cysteines is absent. In the context of models in which each μ chain interacts with only two other μ chains, these results suggest that some molecules are like Figure 1C and some like Figure 1D. However, the availability of three cysteines for inter-μ chain bonding suggests that the μ chains might each bind three other μ chains, as illustrated in Figure 2. In the same spirit, Figure 2C presents a model for a J chain-containing pentamer that reflects evidence that the J chain joins μ chains that are not joined to other μ chains by the cysteines in the Cμ3 domains. These and other models, both regular and irregular are discussed elsewhere. [27] [33]

Figure 2. Some alternative ways of linking m chains A, B) These figures depict two of many possible models of inter-m chain disulfide bonding in hexameric IgM. As in Figure 1, the Cm2 disulfide bonds and the Cm4tp disulfide bonds are represented by a red double arrowhead, and the Cm3 disulfide bonds are represented by the long double-headed arrows. In both models A and B each type of disulfide bond (Cm2-Cm2; Cm3-Cm3; Cm4tp-Cm4tp) joins m chains eries with each of the others. Methods for distinguishing these and other models are discussed in reference [28]. C) This representation of pentameric IgM illustrates how the J chain might be bonded to m chains that are not linked via Cm3 disulfide bonds Some alternative ways of linking u chains.jpg
Figure 2. Some alternative ways of linking μ chains
A, B) These figures depict two of many possible models of inter-μ chain disulfide bonding in hexameric IgM. As in Figure 1, the Cμ2 disulfide bonds and the Cμ4tp disulfide bonds are represented by a red double arrowhead, and the Cμ3 disulfide bonds are represented by the long double-headed arrows. In both models A and B each type of disulfide bond (Cμ2-Cμ2; Cμ3-Cμ3; Cμ4tp-Cμ4tp) joins μ chains eries with each of the others. Methods for distinguishing these and other models are discussed in reference [28].
C) This representation of pentameric IgM illustrates how the J chain might be bonded to μ chains that are not linked via Cμ3 disulfide bonds

Pentameric IgM is typically represented as containing a single J chain per polymer, but in actuality the measurements of J chain stoichiometry have ranged from one J molecule per polymer to three J molecules per polymer. [34] [35] [36] [37] The wide range might be due to technical problems, such as incomplete radiolabeling or imprecisely quantitating an Ouchterlony line. However, the variation might also be due to heterogeneity in the IgM preparations, i.e., the various preparations might have differed substantially in their content of J-containing and J-deficient polymers.

Tertiary and quaternary structure of the μ constant region

Individual C2, C3, and C4tp domains were generated independently in E. coli and then studied using a range of approaches, including sedimentation rate, X-ray crystallography, and NMR spectroscopy, to obtain insight into the detailed three-dimensional structure of the chain. The domains of the heavy chain, like those of other immunoglobulins, have the distinctive overlaying -sheets of seven strands, which are stabilized by intra-domain disulfide linkages. Overall, the IgM constant region has a "mushroom-like" shape, with the C2-C3 domains forming a disk similar to the mushroom's head and the C4tp domains protruding like a short stem. [38]

Function

IgM interacts with several other physiological molecules:

  1. IgM can bind complement component C1 and activate the classical pathway, leading to opsonization of antigens and cytolysis.
  2. IgM binds to the polyimmunoglobulin receptor (pIgR) in a process that brings IgM to mucosal surfaces, such as the gut lumen and into breast milk. This binding depends on the J chain. [39]
  3. Two other Fc receptors that bind IgM—Fcα/μ-R and Fcμ-R -- have been detected. Fcα/μ-R, like pIgR, binds polymeric IgM and IgA. Fcα/μ-R can mediate endocytosis, and its expression in the gut suggests a role in mucosal immunity. Fcμ-R (formerly known as Toso/Faim3) binds IgM exclusively and can mediate cellular uptake of IgM-conjugated antigen. [40] Inactivation of the corresponding genes in knock-out mice produces a phenotype, but the physiological functions of these receptors are still uncertain [41]

Regulation of the immune response

Specific immunoglobulins that are injected into animals together with their antigen can influence the antibody response to this same antigen. [42] Endogenous antibodies produced after a primary immunization can also affect the antibody response to a booster immunization, suggesting that similar effects occur during physiological conditions. The ”regulatory” effects can be either positive or negative. That is, depending on the type of antigen and the isotype of the antibody, the effect can be suppression or enhancement of the antibody response. Such effects are well illustrated by experiments involving immunization with xenogenic (foreign) erythrocytes (red blood cells). For example, when IgG is administered together with xenogenic erythrocytes, this combination causes almost complete suppression of the erythrocyte-specific antibody response. This effect is used clinically to prevent Rh-negative mothers from becoming immunized against fetal Rh-positive erythrocytes, and its use has dramatically decreased the incidence of hemolytic disease in newborns. [43] In contrast to the effect of IgG, antigen-specific IgM can greatly enhance the antibody response, especially in the case of large antigens. [44] Thus, when IgM specific for erythrocytes is injected into animals (including humans) together with erythrocytes, a much stronger antibody response to the erythrocytes is induced than when erythrocytes are administered alone. Several lines of evidence indicate that the ability of IgM to activate complement is required for its enhancing effect. That is, IgM-mediated enhancement does not occur in animals that have been depleted for complement component C3, nor in mutant animals lacking complement receptors 1 and 2. Similarly, mutant IgM that cannot activate complement does not enhance the immune response. A possible explanation for IgM-mediated enhancement is that B lymphocytes capture IgM-antigen-complement complexes and transport the complexes into areas in the spleen where efficient immune responses are generated. Because IgM is produced early in an immune response, this might be important in the initiation of antibody responses.[ citation needed ]

Synthesis

In germ-line cells (sperm and ova) the genes that will eventually encode immunoglobulins are not in a functional form (see V(D)J recombination). In the case of the heavy chain, three germ-line segments denoted V, D and J are ligated together and adjoined to the DNA encoding the μ heavy chain constant region. Early in ontogeny, B cells express both the μ and the δ heavy chains; co-expression of these two heavy chains, each bearing the same V domain depends on alternative splicing and alternative poly-A addition sites. The expression of the other isotypes (γ, ε and α) is affected by another type of DNA rearrangement, a process called Immunoglobulin class switching. [45]

Clinical significance

IgM is the first immunoglobulin expressed in the human fetus (around 20 weeks) [46] and phylogenetically the earliest antibody to develop. [47]

IgM antibodies appear early in the course of an infection and usually reappear, to a lesser extent, after further exposure. IgM antibodies do not pass across the human placenta (only isotype IgG). [48]

These two biological properties of IgM make it useful in the diagnosis of infectious diseases. Demonstrating IgM antibodies in a patient's serum indicates recent infection, or in a neonate's serum indicates intrauterine infection (e.g. congenital rubella syndrome).

The development of anti-donor IgM after organ transplantation is not associated with graft rejection but it may have a protective effect. [49]

IgM in normal serum is often found to bind to specific antigens, even in the absence of prior immunization. [50] For this reason, IgM has sometimes been called a "natural antibody". This phenomenon is probably due to the high avidity of IgM that allows it to bind detectably even to weakly cross-reacting antigens that are naturally occurring. For example, the IgM antibodies that bind to the red blood cell A and B antigens might be formed in early life as a result of exposure to A- and B-like substances that are present in bacteria or perhaps also in plant materials.

IgM antibodies are mainly responsible for the clumping (agglutination) of red blood cells if the recipient of a blood transfusion receives blood that is not compatible with their blood type.

A mutation of the mu chain within IgM causes autosomal recessive agammaglobulinemia. [51]

The presence of IgM or, rarely, IgG is one of the obligate criteria for a diagnosis of Schnitzler's syndrome. [52] [53]

See also

Related Research Articles

<span class="mw-page-title-main">Antibody</span> Protein(s) forming a major part of an organisms immune system

An antibody (Ab) is the secreted form of a B cell receptor; the term immunoglobulin (Ig) can refer to either the membrane-bound form or the secreted form of the B cell receptor, but they are, broadly speaking, the same protein, and so the terms are often treated as synonymous. Antibodies are large, Y-shaped proteins belonging to the immunoglobulin superfamily which are used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that cause disease. Antibodies can recognize virtually any size antigen with diverse chemical compositions from molecules. Each antibody recognizes one or more specific antigens. Antigen literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each tip of the "Y" of an antibody contains a paratope that specifically binds to one particular epitope on an antigen, allowing the two molecules to bind together with precision. Using this mechanism, antibodies can effectively "tag" a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly.

<span class="mw-page-title-main">Immunoglobulin G</span> Antibody isotype

Immunoglobulin G (IgG) is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. Each IgG antibody has two paratopes.

<span class="mw-page-title-main">Immunoglobulin A</span> Antibody that plays a crucial role in the immune function of mucous membranes

Immunoglobulin A is an antibody that plays a role in the immune function of mucous membranes. The amount of IgA produced in association with mucosal membranes is greater than all other types of antibody combined. In absolute terms, between three and five grams are secreted into the intestinal lumen each day. This represents up to 15% of total immunoglobulins produced throughout the body.

<span class="mw-page-title-main">Immunoglobulin D</span> Antibody isotype

Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually co-expressed with another cell surface antibody called IgM. IgD is also produced in a secreted form that is found in very small amounts in blood serum, representing 0.25% of immunoglobulins in serum. The relative molecular mass and half-life of secreted IgD is 185 kDa and 2.8 days, respectively. Secreted IgD is produced as a monomeric antibody with two heavy chains of the delta (δ) class, and two Ig light chains.

<span class="mw-page-title-main">CD4</span> Marker on immune cells

In molecular biology, CD4 is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as helper T cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984. In humans, the CD4 protein is encoded by the CD4 gene.

<span class="mw-page-title-main">T-cell receptor</span> Protein complex on the surface of T cells that recognizes antigens

The T-cell receptor (TCR) is a protein complex found on the surface of T cells, or T lymphocytes, that is responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. The binding between TCR and antigen peptides is of relatively low affinity and is degenerate: that is, many TCRs recognize the same antigen peptide and many antigen peptides are recognized by the same TCR.

<span class="mw-page-title-main">Immunoglobulin heavy chain</span> Large polypeptide subunit of an antibody

The immunoglobulin heavy chain (IgH) is the large polypeptide subunit of an antibody (immunoglobulin). In human genome, the IgH gene loci are on chromosome 14.

<span class="mw-page-title-main">Fc receptor</span> Surface protein important to the immune system

In immunology, an Fc receptor is a protein found on the surface of certain cells – including, among others, B lymphocytes, follicular dendritic cells, natural killer cells, macrophages, neutrophils, eosinophils, basophils, human platelets, and mast cells – that contribute to the protective functions of the immune system. Its name is derived from its binding specificity for a part of an antibody known as the Fc region. Fc receptors bind to antibodies that are attached to infected cells or invading pathogens. Their activity stimulates phagocytic or cytotoxic cells to destroy microbes, or infected cells by antibody-mediated phagocytosis or antibody-dependent cell-mediated cytotoxicity. Some viruses such as flaviviruses use Fc receptors to help them infect cells, by a mechanism known as antibody-dependent enhancement of infection.

<span class="mw-page-title-main">B-cell receptor</span> Transmembrane protein on the surface of a B cell

The B-cell receptor (BCR) is a transmembrane protein on the surface of a B cell. A B-cell receptor is composed of a membrane-bound immunoglobulin molecule and a signal transduction moiety. The former forms a type 1 transmembrane receptor protein, and is typically located on the outer surface of these lymphocyte cells. Through biochemical signaling and by physically acquiring antigens from the immune synapses, the BCR controls the activation of the B cell. B cells are able to gather and grab antigens by engaging biochemical modules for receptor clustering, cell spreading, generation of pulling forces, and receptor transport, which eventually culminates in endocytosis and antigen presentation. B cells' mechanical activity adheres to a pattern of negative and positive feedbacks that regulate the quantity of removed antigen by manipulating the dynamic of BCR–antigen bonds directly. Particularly, grouping and spreading increase the relation of antigen with BCR, thereby proving sensitivity and amplification. On the other hand, pulling forces delinks the antigen from the BCR, thus testing the quality of antigen binding.

<span class="mw-page-title-main">Protein A</span>

Protein A is a 42 kDa surface protein originally found in the cell wall of the bacteria Staphylococcus aureus. It is encoded by the spa gene and its regulation is controlled by DNA topology, cellular osmolarity, and a two-component system called ArlS-ArlR. It has found use in biochemical research because of its ability to bind immunoglobulins. It is composed of five homologous Ig-binding domains that fold into a three-helix bundle. Each domain is able to bind proteins from many mammalian species, most notably IgGs. It binds the heavy chain within the Fc region of most immunoglobulins and also within the Fab region in the case of the human VH3 family. Through these interactions in serum, where IgG molecules are bound in the wrong orientation, the bacteria disrupts opsonization and phagocytosis.

<span class="mw-page-title-main">Immunoglobulin superfamily</span> Large protein superfamily of cell surface and soluble proteins

The immunoglobulin superfamily (IgSF) is a large protein superfamily of cell surface and soluble proteins that are involved in the recognition, binding, or adhesion processes of cells. Molecules are categorized as members of this superfamily based on shared structural features with immunoglobulins ; they all possess a domain known as an immunoglobulin domain or fold. Members of the IgSF include cell surface antigen receptors, co-receptors and co-stimulatory molecules of the immune system, molecules involved in antigen presentation to lymphocytes, cell adhesion molecules, certain cytokine receptors and intracellular muscle proteins. They are commonly associated with roles in the immune system. Otherwise, the sperm-specific protein IZUMO1, a member of the immunoglobulin superfamily, has also been identified as the only sperm membrane protein essential for sperm-egg fusion.

<span class="mw-page-title-main">Complementarity-determining region</span> Part of the variable chains in immunoglobulins and T cell receptors

Complementarity-determining regions (CDRs) are polypeptide segments of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively. CDRs are where these molecules bind to their specific antigen and their structure/sequence determines the binding activity of the respective antibody. A set of CDRs constitutes a paratope, or the antigen-binding site. As the most variable parts of the molecules, CDRs are crucial to the diversity of antigen specificities generated by lymphocytes.

<span class="mw-page-title-main">Immunoglobulin class switching</span> Biological mechanism

Immunoglobulin class switching, also known as isotype switching, isotypic commutation or class-switch recombination (CSR), is a biological mechanism that changes a B cell's production of immunoglobulin from one type to another, such as from the isotype IgM to the isotype IgG. During this process, the constant-region portion of the antibody heavy chain is changed, but the variable region of the heavy chain stays the same. Since the variable region does not change, class switching does not affect antigen specificity. Instead, the antibody retains affinity for the same antigens, but can interact with different effector molecules.

<span class="mw-page-title-main">Isotype (immunology)</span>

In immunology, antibodies are classified into several types called isotypes or classes. The variable (V) regions near the tip of the antibody can differ from molecule to molecule in countless ways, allowing it to specifically target an antigen . In contrast, the constant (C) regions only occur in a few variants, which define the antibody's class. Antibodies of different classes activate distinct effector mechanisms in response to an antigen . They appear at different stages of an immune response, differ in structural features, and in their location around the body.

<span class="mw-page-title-main">J chain</span> Protein-coding gene in the species Homo sapiens

The Joining (J) chain is a protein component that links monomers of antibodies IgM and IgA to form polymeric antibodies capable of secretion. The J chain is well conserved in the animal kingdom, but its specific functions are yet to be fully understood. It is a 137 residue polypeptide, encoded by the IGJ gene.

<span class="mw-page-title-main">Polymeric immunoglobulin receptor</span> Protein-coding gene in the species Homo sapiens

Polymeric immunoglobulin receptor (pIgR) is a transmembrane protein that in humans is encoded by the PIGR gene. It is an Fc receptor which facilitates the transcytosis of the soluble polymeric isoforms of immunoglobulin A and immunoglobulin M (pIg) and immune complexes. pIgRs are mainly located on the epithelial lining of mucosal surfaces of the gastrointestinal tract. The composition of the receptor is complex, including 6 immunoglobulin-like domains, a transmembrane region, and an intracellular domain. pIgR expression is under the strong regulation of cytokines, hormones, and pathogenic stimuli.

<span class="mw-page-title-main">IGHE</span>

Ig epsilon chain C region is a protein that in humans is encoded by the IGHE gene.

<span class="mw-page-title-main">CD79A</span> Mammalian protein found in Homo sapiens

Cluster of differentiation CD79A also known as B-cell antigen receptor complex-associated protein alpha chain and MB-1 membrane glycoprotein, is a protein that in humans is encoded by the CD79A gene.

<span class="mw-page-title-main">FCAR</span> Mammalian protein found in Homo sapiens

Fc fragment of IgA receptor (FCAR) is a human gene that codes for the transmembrane receptor FcαRI, also known as CD89. FcαRI binds the heavy-chain constant region of Immunoglobulin A (IgA) antibodies. FcαRI is present on the cell surface of myeloid lineage cells, including neutrophils, monocytes, macrophages, and eosinophils, though it is notably absent from intestinal macrophages and does not appear on mast cells. FcαRI plays a role in both pro- and anti-inflammatory responses depending on the state of IgA bound. Inside-out signaling primes FcαRI in order for it to bind its ligand, while outside-in signaling caused by ligand binding depends on FcαRI association with the Fc receptor gamma chain.

A heavy-chain antibody is an antibody which consists only of two heavy chains and lacks the two light chains usually found in antibodies.

References

  1. ↑ "Immunoglobulin M". The American Heritage Dictionary of the English Language (Fourth ed.). Houghton Mifflin Company. 2004. ISBN   978-0618082308.
  2. ↑ Alberts, B.; Johnson, A.; Lewis, J.; Walter, P.; Raff, M.; Roberts, K. (2002). "Chapter 24". Molecular Biology of the Cell (4th ed.). Routledge. ISBN   978-0-8153-3288-6.
  3. ↑ Capolunghi, F.; Rosado, M. M.; Sinibaldi, M.; Aranburu, A.; Carsetti, R. (2013). "Why do we need IgM memory B cells?". Immunology Letters . 152 (2): 114–20. doi:10.1016/j.imlet.2013.04.007. PMID   23660557.
  4. ↑ Williams, N.; O'Connell, P. R. (2008). "Chapter 62". Bailey & Love's Short Practice of Surgery (25th ed.). CRC Press. p. 1102. ISBN   9780340939321.
  5. ↑ Heidelberger, M.; Pedersen, K. O. (1937). "The molecular weight of antibodies". Journal of Experimental Medicine . 65 (3): 393–414. doi:10.1084/jem.65.3.393. PMC   2133497 . PMID   19870608.
  6. ↑ Kabat, E. A. (1939). "The molecular weight of antibodies". Journal of Experimental Medicine . 69 (1): 103–118. doi:10.1084/jem.69.1.103. PMC   2133729 . PMID   19870830.
  7. ↑ Waldenström, J. (1943). "Incipient myelomatisis or "essential" hyoerglobulinemis with fibrinogenopenia—a new syndrome?". Acta Medica Scandinavica . 142 (3–4): 216–247. doi:10.1111/j.0954-6820.1944.tb03955.x.
  8. ↑ Potter, M. (2007). The early history of plasma cell tumors in mice, 1954-1976. Vol. 98. pp. 17–51. doi:10.1016/S0065-230X(06)98002-6. ISBN   9780123738967. PMID   17433907.{{cite book}}: |journal= ignored (help)
  9. ↑ Monica, T. J.; Williams, S. B.; Goochee, C. F.; Maiorella, B. L. (1995). "Characterization of the glycosylation of a human IgM produced by a human-mouse hybridoma". Glycobiology . 5 (2): 175–185. doi:10.1093/glycob/5.2.175. PMID   7780192.
  10. ↑ Heyman, B.; Shulman, M. J. (2016). "Structure, Function, and Production of Immunoglobulin M (IgM)". In Ratcliffe, M. (ed.). Encyclopedia of Immunobiology. Vol. 2. Elsevier. pp. 1–14. doi:10.1016/B978-0-12-374279-7.05001-3. ISBN   978-0-12-374279-7.
  11. ↑ Beale, D.; Feinstein, A. (1969). "Studies on the Reduction of a Human 19S Immunoglobulin M". Biochemical Journal . 112 (2): 187–194. doi:10.1042/bj1120187. PMC   1187691 . PMID   4979347.
  12. ↑ Milstein, C.P.; et al. (1975). "Interchain disulfide bridges of mouse Immunoglobulin M". Biochemical Journal . 151 (3): 615–624. doi:10.1042/bj1510615. PMC   1172409 . PMID   766753.
  13. ↑ Halpern, M. S.; Koshland, M. E. (1970). "Novel subunit of secretory IgA". Nature . 228 (5278): 1276–1278. Bibcode:1970Natur.228.1276H. doi:10.1038/2281276a0. PMID   5530654. S2CID   36189290.
  14. ↑ Mestecky, J.; Zikin, J.; Butler, W. T. (1971). "Immunoglobulin M an secretory immunoglobulin A: presence of common polypeptide chain different from light chains". Science . 171 (3976): 1163–1165. Bibcode:1971Sci...171.1163M. doi:10.1126/science.171.3976.1163. PMID   5544873. S2CID   6834561.
  15. ↑ Frutiger, S.; et al. (1992). "Disulfide bond assignment in human J chain and its covalent pairing with immunoglobulin M". Biochemistry . 31 (50): 12643–12647. doi:10.1021/bi00165a014. PMID   1472500.
  16. ↑ Johansen, F. E.; Braathen, R.; Brandtzaeg, P. (2000). "Role of J chain in secretory immunoglobulin formation". Scandinavian Journal of Immunology . 52 (3): 240–8. doi: 10.1046/j.1365-3083.2000.00790.x . PMID   10972899.
  17. ↑ Sørensen, V.; et al. (2000). "Structural requirements for incorporation of J chain into human IgM and IgA". International Immunology . 12 (1): 19–27. doi: 10.1093/intimm/12.1.19 . PMID   10607746.
  18. 1 2 Cattaneo, A.; Neuberger, M. S. (1987). "Polymeric immunoglobulin M is secreted by transfectants of non-lymphoid cells in the absence of immunoglobulin J chain". The EMBO Journal . 6 (9): 2753–2758. doi:10.1002/j.1460-2075.1987.tb02569.x. PMC   553699 . PMID   3119328.
  19. ↑ Fazel, S.; Wiersma, E. J.; Shulman, M. J. (1997). "Interplay of J chain and disulfide bonding in assembly of polymeric IgM". International Immunology . 9 (8): 1149–1158. doi: 10.1093/intimm/9.8.1149 . hdl: 1807/11898 . PMID   9263012.
  20. ↑ Parkhouse, R.; Askonas, B. A.; Dourmashkin, R. R. (1970). "Electron microscopic studies of mouse immunoglobulin M; structure and reconstitution following reduction". Immunology . 18 (4): 575–584. PMC   1455497 . PMID   5421036.
  21. ↑ Schwager, J.; Hadji-Azlmi, I. (1984). "Mitogen-induced B-cell differentiation in Xenopus laevis". Differentiation . 27 (3): 182–188. doi:10.1111/j.1432-0436.1984.tb01426.x. PMID   6334001.
  22. ↑ Fillatreau, S.; et al. (2013). "The astonishing diversity of Ig classes and B cell repertoires in teleost fish". Frontiers in Immunology . 4: 1–14. doi: 10.3389/fimmu.2013.00028 . PMC   3570791 . PMID   23408183.
  23. ↑ Getahun, A.; et al. (1999). "Influence of the μ-chain C-terminal sequence on polymerization of immunoglobulin M". Immunology . 97 (3): 408–413. doi:10.1046/j.1365-2567.1999.00797.x. PMC   2326861 . PMID   10447761.
  24. ↑ Dolder, F. (1971). "Occurrence, Isolation and Interchain Bridges of Natural 7-S Immunoglobulin M in Human Serum". Biochimica et Biophysica Acta . 236 (3): 675–685. PMID   4997811.
  25. ↑ Eskeland, T.; Christensen, T. B. (1975). "IgM molecules with and without J chain in serum and after purification, studied by ultracentrifugation, electrophoresis, and electron microsopy". Scandinavian Journal of Immunology . 4 (3): 217–228. doi:10.1111/j.1365-3083.1975.tb02620.x. PMID   807966. S2CID   8246173.
  26. ↑ Davis, A. C.; Roux, K. H.; Shulman, M. J. (1988). "On the structure of polymeric IgM". European Journal of Immunology . 18 (7): 1001–1008. doi:10.1002/eji.1830180705. PMID   3136022. S2CID   34679165.
  27. 1 2 Davis, A. C.; et al. (1989). "Intermolecular disulfide bonding in IgM: effects of replacing cysteine residues in the μ heavy chain". The EMBO Journal . 8 (9): 2519–2526. doi:10.1002/j.1460-2075.1989.tb08389.x. PMC   401247 . PMID   2511005.
  28. ↑ Collins, C.; Tsui, F. W.; Shulman, M. J. (2002). "Differential activation of human and guinea pig complement by pentameric and hexameric IgM". European Journal of Immunology . 32 (6): 1802–1810. doi: 10.1002/1521-4141(200206)32:6<1802::AID-IMMU1802>3.0.CO;2-C . PMID   12115664.
  29. ↑ Davis, A. C.; et al. (1989). "Mutations of the mouse m H chain which prevent polymer assembly". Journal of Immunology . 43 (4): 1352–1357. doi: 10.4049/jimmunol.143.4.1352 . PMID   2501393. S2CID   40558731.
  30. ↑ Smith, R. I. F.; Coloma, M. J.; Morrison, S. L. (1995). "Addition of a mu-tailpiece to IgG results in polymeric antibodies with enhanced effector functions including complement-mediated cytolysis by IgG4". Journal of Immunology . 154 (5): 2226–2236. doi: 10.4049/jimmunol.154.5.2226 . PMID   7868896. S2CID   10506582.
  31. ↑ Sørensen, V.; et al. (1996). "Effect of the IgM and IgA secretory tailpieces on polymerization and secretion of IgM and IgG". Journal of Immunology . 156 (8): 2858–2865. doi: 10.4049/jimmunol.156.8.2858 . PMID   8609405. S2CID   23601980.
  32. ↑ Smith, R.; Morrison, S. L. (1994). "Recombinant polymeric IgG: An approach to engineering more potent antibodies". Nature Biotechnology . 12 (7): 683–688. doi:10.1038/nbt0794-683. PMID   7764912. S2CID   19055205.
  33. ↑ Wiersma, E. J.; Shulman, M. J. (1995). "Assembly of IgM: role of disulfide bonding and noncovalent interactions". Journal of Immunology . 154 (10): 5265–5272. doi: 10.4049/jimmunol.154.10.5265 . PMID   7730630. S2CID   22148157.
  34. ↑ Chapuis, R. M.; Koshland, M. E. (1974). "Mechanism of IgM polymerization". Proc. Natl. Acad. Sci. U.S.A. 71 (3): 657–661. Bibcode:1974PNAS...71..657C. doi: 10.1073/pnas.71.3.657 . PMC   388071 . PMID   4207070.
  35. ↑ Mihaesco, C.; Mihaesco, E.; Metzger, H. (1973). "Variable J-chain content in human IgM". FEBS Letters . 37 (2): 303–306. doi: 10.1016/0014-5793(73)80483-1 . PMID   4202824. S2CID   41601548.
  36. ↑ Brandtzaeg, P. (1976). "Complex formation between secretory component and human immunoglobulin related to their content of J chain". Scandinavian Journal of Immunology . 5 (4): 411–419. doi:10.1111/j.1365-3083.1976.tb00295.x. PMID   821140. S2CID   39847718.
  37. ↑ Grubb, A. O. (1978). "Quantitation of J chain in human biological fluids by a simple immunochemical procedure". Acta Medica Scandinavica . 204 (1–6): 453–465. doi:10.1111/j.0954-6820.1978.tb08473.x. PMID   104551.
  38. ↑ Müller, R.; et al. (2013). "High-resolutiion structures of the IgM Fc domainsreveal principles of its hexamer formation". Proc. Natl. Acad. Sci. U.S.A. 110 (25): 10183–10188. Bibcode:2013PNAS..11010183M. doi: 10.1073/pnas.1300547110 . PMC   3690842 . PMID   23733956.
  39. ↑ Johansen, F. E.; Braathen, R.; Brandtzaeg, P. (2000). "Role of J chain in secretory immunoglobulin formation". Scandinavian Journal of Immunology . 52 (3): 240–8. doi: 10.1046/j.1365-3083.2000.00790.x . PMID   10972899.
  40. ↑ Shima, H.; et al. (2010). "Identification of TOSO/FAIM3 as an Fc receptor for IgM". Int. Immunol. 22 (3): 149–56. doi: 10.1093/intimm/dxp121 . PMID   20042454.
  41. ↑ Ouchida, R.; et al. (2012). "Critical role of the IgM Fc receptor in IgM homeostasis, B-cell survival, and humoral immune responses". Proc. Natl. Acad. Sci. U.S.A. 109 (40): E2699–706. Bibcode:2012PNAS..109E2699O. doi: 10.1073/pnas.1210706109 . PMC   3479561 . PMID   22988094.
  42. ↑ Heyman, B (2013). Antibody mediated regulation of humoral immunity. in Nimmerjahn, F. (ed.) Molecular and cellular mechanisms of antibody activity: Springer.
  43. ↑ Urbaniak, S. J. & Greiss, M. A. (2000). "RhD haemolytic disease of the fetus and the newborn". Blood Rev. 14 (1): 33–61. doi:10.1054/blre.1999.0123. PMID   10805260.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  44. ↑ Sörman A, Zhang L, Ding Z, Heyman, B. (2014). "How antibodies use complement to regulate antibody responses". Mol. Immunol. 61 (2): 79–88. doi: 10.1016/j.molimm.2014.06.010 . PMID   25001046.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  45. ↑ Murphy, K.; Weaver, C. (2016). Janeway's Immunobiology. New York, NY: Garland Science/Taylor and Francis. p. 195. ISBN   9780815345053.
  46. ↑ van Furth, R.; Schuit, H. R.; Hijmans, W. (1965). "The immunological development of the human fetus". Journal of Experimental Medicine . 122 (6): 1173–88. doi:10.1084/jem.122.6.1173. PMC   2138097 . PMID   4159036.
  47. ↑ Review of Medical Physiology by William Francis Ganong
  48. ↑ Matthews, T. G.; O'Herlihy, C. (November 1978). "Significance of raised immunoglobulin M levels in cord blood of small-for-gestational-age infants". Archives of Disease in Childhood. 53 (11): 895–898. doi:10.1136/adc.53.11.895. ISSN   1468-2044. PMC   1545275 . PMID   727813.
  49. ↑ McAlister, C. C.; et al. (2004). "Protective anti-donor IgM production after crossmatch positive liver-kidney transplantation". Liver Transplantation . 10 (2): 315–9. doi: 10.1002/lt.20062 . PMID   14762873.
  50. ↑ Jayasekera, J. P.; Moseman, E. A.; Carroll, M. C. (2007). "Natural antibody and complement mediate neutralization of influenza virus in the absence of prior immunity". Journal of Virology . 81 (7): 3487–94. doi:10.1128/JVI.02128-06. PMC   1866020 . PMID   17202212.
  51. ↑ "OMIM Entry - # 601495 - AGAMMAGLOBULINEMIA 1, AUTOSOMAL RECESSIVE; AGM1". omim.org. Retrieved 2021-03-25.
  52. ↑ Gusdorf, L.; Lipsker, D. (17 July 2017). "Schnitzler Syndrome: a Review". Current Rheumatology Reports. 19 (8): 46. doi:10.1007/s11926-017-0673-5. PMID   28718061. S2CID   13780498.
  53. ↑ Simon, A.; Asli, B.; Braun-Falco, M.; Koning, H. De; Fermand, J.-P.; Grattan, C.; Krause, K.; Lachmann, H.; Lenormand, C.; Martinez-Taboada, V.; Maurer, M.; Peters, M.; Rizzi, R.; Rongioletti, F.; Ruzicka, T.; Schnitzler, L.; Schubert, B.; Sibilia, J.; Lipsker, D. (2013). "Schnitzler's syndrome: diagnosis, treatment, and follow-up". Allergy. 68 (5): 562–568. doi: 10.1111/all.12129 . PMID   23480774. S2CID   12831354.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.