Changes

[[Image:LH IgG.png|thumb|250px|right|'''IgG''']]

[[Image:LH IgG.png|thumb|150px|right|'''IgG''']]

[[Image:IgG.jpg|thumb|right|250px|IgG - B. Catchpole, RVC 2008]]

[[Image:IgG.jpg|thumb|right|150px|IgG - B. Catchpole, RVC 2008]]

 

<p>IgG is the major antibody in blood plasma and constitutes at least 80% of all antibody in the body. It is the smallest immunoglobulin so it can readily leave the blood plasma and enter tissues.</p>

 

IgG is the major antibody in blood plasma, and constitutes at least 80% of all antibodies in the body. It is the smallest immunoglobulin, so can readily leave the blood plasma and enter tissues.

 

==Structure==

==Structure==

<p>IgG is Y-shaped with three constant regions and a heavy chain subunit type γ. There are several different IgG subclasses depending on the species coded for by the IGHG gene.  

 

*Ruminants have three subclasses

IgG is Y-shaped, with three constant regions and a heavy chain subunit type γ. There are several different IgG subclasses, depending on the species coded for by the IGHG gene.  

**G1-G3

 

**IgG1 is the major antibody in ruminant mucosal secretions and colostrum

'''Ruminants'''

* Dogs, rodents (and cats?) have four subclasses

 

**Dogs: G1-G4

Have three subclasses, G1-G3. IgG1 is the major antibody in ruminant mucosal secretions and colostrum.

**Rodents: G1-G3 (G2a, G2b)

 

*Pigs have five subclasses

'''Dogs, rodents and cats'''

**G1-G4 (G2a, G2b)

 

*Horses have six subclasses  

Have four subclasses. Dogs: G1-G4; Rodents: G1-G3 (G2a, G2b). Cats are unknown.

**G1-G6</p>

 

'''Pigs'''

 

Have five subclasses, G1-G4 (G2a, G2b).

 

'''Horses'''

 

Have six subclasses, G1-G6.

 

==Production==

==Production==

<p>IgG is produced by plasma cells in the spleen, bone marrow and lymph nodes.</p>

 

IgG is produced by plasma cells in the spleen, bone marrow and lymph nodes.

 

==Function==

==Function==

 

*Some IgG subclasses can activate complement via the classical pathway

Some IgG subclasses can activate complement via the classical pathway. Some subclasses act as targets for macrophages, eosinophils and [[Neutrophils|neutrophils]]. It is therefore the major antibody in tissue fluids and lymph. IgG specifically binds to antigens on bacteria, causing agglutination and opsonisation.

*Some subclasses act as targets for macrophages, eosinophils and [[Neutrophils|neutrophils]]

 

** It is therefore the major antibody in tissue fluids and lymph

*IgG specifically binds to antigens on bacteria

 

**Causing agglutination and opsonisation</p>

[[Immunoglobulins|Immunoglobulins]]

 

[[Immunoglobulin A|Immunoglobulin A]]

<center><b>^{[[Immunoglobulins|Immunoglobulins]]: [[Immunoglobulin A|Immunoglobulin A]], [[Immunoglobulin D|Immunoglobulin D]], [[Immunoglobulin E|Immunoglobulin E]], [[Immunoglobulin G|Immunoglobulin G]] & [[Immunoglobulin M|Immunoglobulin M]]}</b></center>

 

[[Immunoglobulin D|Immunoglobulin D]]

 

[[Immunoglobulin E|Immunoglobulin E]]

 

[[Immunoglobulin M|Immunoglobulin M]]

[[Category:Immunoglobulins]]

[[Category:Immunoglobulins]]

[[Category:Image Review]]

[[Category:Image Review]]

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[[Category:To Do - AimeeHicks]]