Immunoglobulins - Overview - Revision history

Bara at 16:03, 2 July 2012

2012-07-02T16:03:25Z

Rjfrancisrvc: /* Degranulation of mast cells/eosinophils */

2012-05-28T11:26:32Z

Degranulation of mast cells/eosinophils

Rjfrancisrvc: /* Immunoglobulin Class Switching */

2012-05-25T10:18:17Z

Immunoglobulin Class Switching

Rjfrancisrvc: /* Immunoglobulin Class Switching */

2012-05-25T10:15:16Z

Immunoglobulin Class Switching

Rjfrancisrvc: /* Immunoglobulin Class Switching */

2012-05-25T10:13:57Z

Immunoglobulin Class Switching

Rjfrancisrvc: /* Structure */

2012-05-25T08:30:28Z

Structure

Rjfrancisrvc: /* Structure */

2012-05-25T08:30:05Z

Structure

Rjfrancisrvc: /* Structure */

2012-05-25T08:29:27Z

Structure

Rjfrancisrvc: /* Degranulation of mast cells/eosinophils */

2012-05-03T11:46:35Z

Degranulation of mast cells/eosinophils

Rjfrancisrvc: /* Degranulation of mast cells/eosinophils */

2012-05-03T11:45:25Z

Degranulation of mast cells/eosinophils

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-{{review}}
+{{OpenPagesTop}}
 [[Image:LH Antibody.png|thumb|200px|right|'''Immunoglobulin''' <br>  Je_at_uwo 2006, WikiMedia Commons]]
 Also known as '''''antibodies
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 <br><br>
 {{Jim Bee 2007}}
 [[Category:Immunoglobulins|A]]
 [[Category:A&P Done]]

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 ==='''Degranulation of [[Mast Cells|mast cells]]/[[Eosinophils|eosinophils]]'''===
-Antibodies play an important role in the [[Innate Immunity Cellular Responses|innate immune response]] to parasites. The Eosinophils and Mast Cells have FcR that are specific to IgE. When the IgE are cross-linked by antigen the eosinophils and Mast cells can interact with the IgE causing the release of their granules through the process known as exocytosis (granule fusion with the plasma membrane). The causes proteolytic enzyme release from eosinophils, and vasoactive peptide and cytokine release by Mast cells which then activates the innate immune response. Interestingly, this response is also responsible for the Type I hypersensitivity reaction.
+Antibodies play an important role in the [[Innate Immunity Cellular Responses|innate immune response]] to parasites. The Eosinophils and Mast Cells have FcR that are specific to IgE. When the IgE are cross-linked by antigen the eosinophils and Mast cells can interact with the IgE causing the release of their granules through the process known as exocytosis (granule fusion with the plasma membrane). This causes proteolytic enzyme release from eosinophils, and vasoactive peptide and cytokine release by Mast cells which then activates the innate immune response. Interestingly, this response is also responsible for the Type I hypersensitivity reaction.
 ==='''[[Complement|Complement fixation]]'''===

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-The first immunoglobulin produced during an immune response is '''always [[IgM]]''' because the Cμ gene is the first constant H chain gene downstream of the variable domain. After antigenic exposure the [[IgM]]+ B-cells differentiate and begin to synthesise other classes of immunoglobulin, but only under the '''direct influence of a T-cell'''. This system is known as '''immunoglobulin heavy chain switching'''. The [[IgG]] antibodies produced in both primary and secondary responses originate from the same clones of B-cells as the [[IgM]] antibodies. The different antibody classes have the same variable domain combinations, and therefore the same antigenic specificity. Under the influence of T-cells, B-cells undergo immunoglobulin heavy chain switching and the B-cells mature from [[IgM]] to [[IgG]] producers and IgE and IgA producers can also be generated. These immunoglobulins tend to be produced within lymphoid tissue associated with mucosal surfaces.
+The first immunoglobulin produced during an immune response is '''always [[IgM]]''' because the Cμ gene is the first constant H chain gene downstream of the variable domain. After antigenic exposure the [[IgM]]<sup>+</sup> B-cells differentiate and begin to synthesise other classes of immunoglobulin, but only under the '''direct influence of a T-cell'''. This system is known as '''immunoglobulin heavy chain switching'''. The [[IgG]] antibodies produced in both primary and secondary responses originate from the same clones of B-cells as the [[IgM]] antibodies. The different antibody classes have the same variable domain combinations, and therefore the same antigenic specificity. Under the influence of T-cells, B-cells undergo immunoglobulin heavy chain switching and the B-cells mature from [[IgM]] to [[IgG]] producers, with [[IgE]] and [[IgA]] producers generated under certain immune responses. These immunoglobulins (IgA and IgE) tend to be produced within lymphoid tissue associated with mucosal surfaces.
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 * '''&alpha; chain - [[IgA]]'''
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-In humans and mice there exists a fifth Ig class, '''[[IgD]] (δ chain)'''. IgD is always expressed on B-cell membranes with [[IgM]] but is ''never secreted''. The sequence of constant region genes on the chromosome is M, G, E and A. In humans/ rodents the Cδ ([[IgD]]) is immediately downstream of the M gene and prior to antigenic stimulation, B-cells express cell membrane-associated [[IgM]]. The first immunoglobulin produced during an immune response is '''always [[IgM]]''' because the Cμ gene is the first constant H chain gene downstream of the variable domain. After antigenic exposure the [[IgM]]+ B-cells differentiate and begin to synthesise other classes of immunoglobulin, but only under the '''direct influence of a T-cell'''. This system is known as '''immunoglobulin heavy chain switching'''. The [[IgG]] antibodies produced in both primary and secondary responses originate from the same clones of B-cells as the [[IgM]] antibodies. The different antibody classes have the same variable domain combinations, and therefore the same antigenic specificity. Under the influence of T-cells, B-cells undergo immunoglobulin heavy chain switching and the B-cells mature from [[IgM]] to [[IgG]] producers and IgE and IgA producers can also be generated. These immunoglobulins tend to be produced within lymphoid tissue associated with mucosal surfaces.
+In humans and mice there exists a fifth Ig class, '''[[IgD]] (δ chain)'''. IgD is always expressed on B-cell membranes with [[IgM]] but is ''never secreted''. The sequence of constant region genes on the chromosome is M, G, E and A. In humans/ rodents the Cδ ([[IgD]]) is immediately downstream of the M gene and prior to antigenic stimulation, B-cells express cell membrane-associated [[IgM]].
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 ===Immunoglobulin Class Switching===
-Different classes of antibody differ from each other in size, charge, amino acid composition, associated carbohydrate and function. Immunoglobulin heavy and light chains are encoded by separate genes with the first 300 bases of each gene encoding the variable part of each protein chain. The combination of the VH and VL contribute to the antigenic specificity and any individual has the capability of producing over 100 million different antibody specificities. The rest of the antibody gene encodes all the constant domains. There are four different types of heavy chain constant domains - μ, γ, ε, α. Different heavy chains are associated with different classes of antibody;
+Different classes of antibody differ from each other in size, charge, amino acid composition, associated carbohydrate and function. Immunoglobulin heavy and light chains are encoded by separate genes with the first 300 bases of each gene encoding the variable part of each protein chain. The combination of the VH and VL contribute to the antigenic specificity and any individual has the capability of producing over 100 million different antibody specificities. The rest of the antibody gene encodes all the constant domains. There are five different types of heavy chain constant domains - μ, γ, ε, α. Different heavy chains are associated with different classes of antibody;
 <br />
 * '''&mu; chain - [[IgM]] '''
 * '''&gamma; chain -[[IgG]]'''
 * '''&epsilon; chain - [[IgE]]'''
 * '''&alpha; chain - [[IgA]]'''
 <br />
 In humans and mice there exists a fifth Ig class, '''[[IgD]] (δ chain)'''. IgD is always expressed on B-cell membranes with [[IgM]] but is ''never secreted''. The sequence of constant region genes on the chromosome is M, G, E and A. In humans/ rodents the Cδ ([[IgD]]) is immediately downstream of the M gene and prior to antigenic stimulation, B-cells express cell membrane-associated [[IgM]]. The first immunoglobulin produced during an immune response is '''always [[IgM]]''' because the Cμ gene is the first constant H chain gene downstream of the variable domain. After antigenic exposure the [[IgM]]+ B-cells differentiate and begin to synthesise other classes of immunoglobulin, but only under the '''direct influence of a T-cell'''. This system is known as '''immunoglobulin heavy chain switching'''. The [[IgG]] antibodies produced in both primary and secondary responses originate from the same clones of B-cells as the [[IgM]] antibodies. The different antibody classes have the same variable domain combinations, and therefore the same antigenic specificity. Under the influence of T-cells, B-cells undergo immunoglobulin heavy chain switching and the B-cells mature from [[IgM]] to [[IgG]] producers and IgE and IgA producers can also be generated. These immunoglobulins tend to be produced within lymphoid tissue associated with mucosal surfaces.

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-At the carboxyl terminus of B-cell expressed Ig is a region that holds the antibody molecule in the cell membrane. Secreted 'free' antibodies do not possess this region. The '''Fab''' fragments of the immunoglobulin is the '''antigen binding fragment''' generated from the light chains when digested by papain (proteolytic enzyme). The  '''Fc''' fragment is the fragment produced by '''papain from the heavy chains''' and this fragment '''mediates [[Phagocytosis|phagocytosis]]''', triggers '''inflammation''', activates '''[[Complement|complement]]''' and '''targets Ig''' to certain tissues.
+At the carboxyl terminus of B-cell expressed Ig is a region that holds the antibody molecule in the cell membrane. Secreted 'free' antibodies do not possess this region. The '''Fab''' fragments of the immunoglobulin is the '''antigen binding fragment''' generated from the light chains when digested by papain (proteolytic enzyme). The  '''Fc''' fragment is the fragment produced by '''papain from the heavy chains''' and this fragment '''mediates [[Phagocytosis|phagocytosis]]''', triggers '''[[Inflammation|inflammation]]''', activates '''[[Complement|complement]]''' and '''targets Ig''' to certain tissues.
 ==Function==