Changes

===Class switching===

===Class switching===

<p>Initially plasma cell produce [[Immunoglobulin M - WikiBlood|IgM]] however this is not always the most appropriate Ig to be produced and therefore stimulation by [[Lymphocytes#Helper CD4+|T cells]] and interleukins causes the plasma cells to undergo class switching to produce different classes of Ig.

<p>Initially plasma cell produce [[Immunoglobulin M|IgM]] however this is not always the most appropriate Ig to be produced and therefore stimulation by [[Lymphocytes#Helper CD4+|T cells]] and interleukins causes the plasma cells to undergo class switching to produce different classes of Ig.

*In mucosal B cells plasma cells CD40 interaction (with Th2 CD40L) and Il-10 stimulates class switching to [[Immunoglobulin A|IgA]]

*In mucosal B cells plasma cells CD40 interaction (with Th2 CD40L) and Il-10 stimulates class switching to [[Immunoglobulin A|IgA]]

*[[Eosinophils|Eosinophils]] produce Il-13 which promotes class switching to [[Immunoglobulin E - WikiBlood|IgE]]</p>

*[[Eosinophils|Eosinophils]] produce Il-13 which promotes class switching to [[Immunoglobulin E - WikiBlood|IgE]]</p>

*Does not require T cell help

*Does not require T cell help

*Activation of B cells by '''non-protinaceous antigens'''

*Activation of B cells by '''non-protinaceous antigens'''

**E.g. Activation by lipopolysaccharides only lead to [[Immunoglobulin M - WikiBlood|IgM]] production

**E.g. Activation by lipopolysaccharides only lead to [[Immunoglobulin M|IgM]] production

**Act as mitogens for the B cells by stimulating cell division

**Act as mitogens for the B cells by stimulating cell division

*Antigens only stimulate '''primary''' immune responses (production of [[Immunoglobulin M - WikiBlood|IgM]])

*Antigens only stimulate '''primary''' immune responses (production of [[Immunoglobulin M|IgM]])

*Do '''not''' stimulate memory cells

*Do '''not''' stimulate memory cells

*There is no diference between the antibody response of the first exposure compared to sunsequent eposures of antigen

*There is no diference between the antibody response of the first exposure compared to sunsequent eposures of antigen

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

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

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

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

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

*[[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

*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  

*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 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 first antibody to be produced in any immune response is [[Immunoglobulin M - WikiBlood|IgM]]

*  The first antibody to be produced in any immune response is [[Immunoglobulin M|IgM]]

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

** 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 - WikiBlood|IgM]]

* 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====

** On the surface of follicular dendritic cells

** On the surface of follicular dendritic cells

** Can stimulate the immune system for years

** Can stimulate the immune system for years

* The level of [[Immunoglobulin M - WikiBlood|IgM]] antibody production is similar to the primary response

* The level of [[Immunoglobulin M|IgM]] antibody production is similar to the primary response

* The increase in antibody production occurs with [[Immunoglobulin G|IgG]]

* The increase in antibody production occurs with [[Immunoglobulin G|IgG]]