Changes

====Primary T Cell Dependent Response====

====Primary T Cell Dependent Response====

* The first exposure of an individual to a particular antigen is referred to as '''priming'''

The first exposure of an individual to a particular antigen is referred to as '''priming'''. The measurable antibody response is called the '''primary immune response'''. The delay of 5-7 days before antibody is produced is called the '''Lag Phase''' during which time the B cells undergo clonal expansion and form plasma cells. IgM antibody is produced first and will begin to appear in the blood; this stage is called the '''Log Phase'''.

* The measurable antibody response is called the '''primary immune response'''

 

*Delay of 5-7 days before antibody is produced which is called the '''Lag Phase'''

The log phase will peak after about 10-14 days and the '''Plateau Phase''' will then occur.

*B cells undergo cloanal expansion and form plasma cells

Class switching occurs replacing decreasing levels of [[Immunoglobulin M|IgM]] with [[Immunoglobulin G|IgG]]. Antibody levels then begin to decline as plasma cells undergo apoptosis.

*IgM antibody is produced first and will begin to appear in the blood. This stage is called the '''Log Phase'''

 

*The log phase will peak after about 10-14 days

*After primary immunisation, it usually takes around 7-10 days for a measurable antibody response to become detectable. This latent period is the time necessary for the antigen to contact specific cells, for the cells involved to interact and expand, and for plasma cells to secrete antibody.

*The '''Plateau Phase''' will then occur

During the primary response, [[Immunoglobulin G|IgG]] production  lags about a week behind that of [[Immunoglobulin M|IgM]].

*[[Immunoglobulins#Immunoglobulin Class Switching|Class switching]] occurs replacing decresing levels of [[Immunoglobulin M|IgM]] with [[Immunoglobulin G|IgG]]

*Antibody levels will then begin to decline as plasma cells undergo apoptosis

*After primary immunisation, it usually takes around 7-10 days for a measurable antibody response to become detectable  

*This latent period is the time necessary for the antigen to contact specific cells, for the cells involved to interact and expand, and for plasma cells to secrete antibody

** This is because the gene that codes the constant domain of [[Immunoglobulin M|IgM]] (Cμ) is directly downstream to the genes that code the variable antibody domain

* During primary response, [[Immunoglobulin G|IgG]] production  lags about a week behind that of [[Immunoglobulin M|IgM]]

====Secondary T Cell Dependent Response====

====Secondary T Cell Dependent Response====