Immunoglobulin D: Difference between revisions

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'''Immunoglobulin D''' (IgD) is an [[antibody]] isotype that plays a complex role in the [[immune system]]. It is present on the surface of many [[B cells]] where it functions as an antigen receptor.  
== Immunoglobulin D ==
 
[[File:Immunoglobulin_D_Mono-und-Polymere.svg|thumb|right|Diagram of Immunoglobulin D structure]]
 
'''Immunoglobulin D''' (IgD) is one of the five major classes of [[immunoglobulins]] (antibodies) found in the immune system of mammals. It is primarily found on the surface of immature [[B cells]] and plays a crucial role in the initiation and regulation of immune responses.


== Structure ==
== Structure ==
Immunoglobulin D, like all [[antibodies]], is a protein structure composed of two heavy chains and two light chains. Each heavy chain has one variable domain followed by three constant domains, while each light chain has one variable domain and one constant domain. The variable domains of the heavy and light chains together form the antigen-binding site.
 
Immunoglobulin D is a monomeric antibody, meaning it consists of a single unit. The structure of IgD is similar to that of other immunoglobulins, with two heavy chains and two light chains forming a Y-shaped molecule. The heavy chains in IgD are of the delta (_) type. The constant region of the delta heavy chain is what distinguishes IgD from other classes of immunoglobulins.


== Function ==
== Function ==
The primary function of IgD is as an antigen receptor on the surface of B cells. When an antigen binds to the IgD molecule, it triggers the B cell to proliferate and differentiate into a plasma cell, which produces large amounts of antibodies to fight the invading pathogen.


== Clinical significance ==
The primary function of IgD is not completely understood, but it is known to be involved in the activation and regulation of [[B cells]]. IgD is expressed on the surface of B cells as a receptor that can bind antigens. This binding is thought to play a role in the activation of B cells and their differentiation into [[plasma cells]] and [[memory B cells]].
Abnormal levels of IgD can be indicative of various health conditions. Elevated levels of IgD may be seen in certain types of [[leukemia]] and [[lymphoma]], as well as in some autoimmune diseases. Low levels of IgD can be seen in individuals with selective IgA deficiency, a condition in which the body does not produce enough of the antibody IgA.
 
IgD is also believed to be involved in the elimination of B cells that produce self-reactive antibodies, thus contributing to the maintenance of [[immune tolerance]].


== See also ==
== Distribution ==
* [[Immunoglobulin]]
 
IgD is found in very low concentrations in the [[blood plasma]] compared to other immunoglobulins such as [[Immunoglobulin G|IgG]] and [[Immunoglobulin M|IgM]]. It is primarily located on the surface of B cells in the [[lymphoid tissues]].
 
== Clinical Significance ==
 
Although IgD is not as well-studied as other immunoglobulins, abnormalities in IgD levels can be associated with certain [[immunodeficiency]] disorders and [[autoimmune diseases]]. Elevated levels of IgD can be seen in some cases of [[chronic infections]] and [[IgD myeloma]], a rare form of [[multiple myeloma]].
 
== Related pages ==
 
* [[Immunoglobulin G]]
* [[Immunoglobulin M]]
* [[B cell]]
* [[B cell]]
* [[Antibody]]
* [[Antibody]]
* [[Immune system]]
* [[Immune system]]
== References ==
<references />
{{stub}}


[[Category:Immunology]]
[[Category:Immunology]]
[[Category:Antibodies]]
[[Category:Antibodies]]
[[Category:Proteins]]
{{dictionary-stub1}}

Revision as of 11:36, 15 February 2025

Immunoglobulin D

File:Immunoglobulin D Mono-und-Polymere.svg
Diagram of Immunoglobulin D structure

Immunoglobulin D (IgD) is one of the five major classes of immunoglobulins (antibodies) found in the immune system of mammals. It is primarily found on the surface of immature B cells and plays a crucial role in the initiation and regulation of immune responses.

Structure

Immunoglobulin D is a monomeric antibody, meaning it consists of a single unit. The structure of IgD is similar to that of other immunoglobulins, with two heavy chains and two light chains forming a Y-shaped molecule. The heavy chains in IgD are of the delta (_) type. The constant region of the delta heavy chain is what distinguishes IgD from other classes of immunoglobulins.

Function

The primary function of IgD is not completely understood, but it is known to be involved in the activation and regulation of B cells. IgD is expressed on the surface of B cells as a receptor that can bind antigens. This binding is thought to play a role in the activation of B cells and their differentiation into plasma cells and memory B cells.

IgD is also believed to be involved in the elimination of B cells that produce self-reactive antibodies, thus contributing to the maintenance of immune tolerance.

Distribution

IgD is found in very low concentrations in the blood plasma compared to other immunoglobulins such as IgG and IgM. It is primarily located on the surface of B cells in the lymphoid tissues.

Clinical Significance

Although IgD is not as well-studied as other immunoglobulins, abnormalities in IgD levels can be associated with certain immunodeficiency disorders and autoimmune diseases. Elevated levels of IgD can be seen in some cases of chronic infections and IgD myeloma, a rare form of multiple myeloma.

Related pages