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Once [[Lymphocytes#T Cells|T cells]] recognise antigen presence in the tissues, they go into action.  Their first response is always to recruit help, which is accomplished by returning to the nearest [[Lymph Nodes - Anatomy & Physiology|lymph node]] to carry out clonal expansion.  Daughter [[Lymphocytes#T Cells|T cells]] are created with identical TCRs in order to recognise the identified antigen.  These daughter cells are then returned to the circulation via the efferent lymph.   
 
Once [[Lymphocytes#T Cells|T cells]] recognise antigen presence in the tissues, they go into action.  Their first response is always to recruit help, which is accomplished by returning to the nearest [[Lymph Nodes - Anatomy & Physiology|lymph node]] to carry out clonal expansion.  Daughter [[Lymphocytes#T Cells|T cells]] are created with identical TCRs in order to recognise the identified antigen.  These daughter cells are then returned to the circulation via the efferent lymph.   
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[[Lymphocytes#T Cells|T cells]] can differentiate three different ways, based on their Cluster of Differentiation (CD) number.  All [[Lymphocytes#T Cells|T cells]] are CD3<sup>+</sup>, and naive circulating [[Lymphocytes#T Cells|T cells]] will differentiate upon interaction with antigen to become either [[Lymphocytes#Cytotoxic CD8+|'''CD8<sup>+</sup> (cytotoxic)''']] or [[Lymphocytes#Helper CD4+|'''CD4<sup>+</sup> (helper)''']] [[Lymphocytes#T Cells|T cells]]. [[Lymphocytes#Helper CD4+|CD4+ T-cells]] will initially become CD4-T<sub>H</sub>0 cells, and must differentiate to [[T cell differentiation#TH1 Cells|T<sub>H</sub>1]], [[T cell differentiation#TH2 Cells|T<sub>H</sub>2]] or [[T cell differentiation#TH17 Cells|T<sub>H</sub>17]] cells depending on the whim of the adaptive response.  T<sub>H</sub>1,  T<sub>H</sub>2 and T<sub>H</sub>17 cells carry out different types of responses: T<sub>H</sub>1 is responsible for enhancing the [[Macrophages|macrophage]] response, whereas T<sub>H</sub>2 cells enhance the [[Lymphocytes#B Cells|B cell]] antibody production, and T<sub>H</sub>17 cells enhance the innate immune response through increased granulocyte trafficking.  Typically, animals produce a balanced response of T<sub>H</sub> cells, though this can lead to pathology, as can a skewed response, depending on the nature of the foreign organism.  For more on [[Lymphocytes#T Cells|T cell]] differentiation, see [[T cell differentiation|here]].
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[[Lymphocytes#T Cells|T cells]] can differentiate three different ways, based on their Cluster of Differentiation (CD) number.  All [[Lymphocytes#T Cells|T cells]] are CD3<sup>+</sup>, and naive circulating [[Lymphocytes#T Cells|T cells]] will differentiate upon interaction with antigen to become either [[Lymphocytes#Cytotoxic CD8+|'''CD8<sup>+</sup> (cytotoxic)''']] or [[Lymphocytes#Helper CD4+|'''CD4<sup>+</sup> (helper)''']] [[Lymphocytes#T Cells|T cells]]. [[Lymphocytes#Helper CD4+|CD4<sup>+</sup> T-cells]] will initially become CD4-T<sub>H</sub>0 cells, and must differentiate to [[T cell differentiation#TH1 Cells|T<sub>H</sub>1]], [[T cell differentiation#TH2 Cells|T<sub>H</sub>2]] or [[T cell differentiation#TH17 Cells|T<sub>H</sub>17]] cells depending on the whim of the adaptive response.  T<sub>H</sub>1,  T<sub>H</sub>2 and T<sub>H</sub>17 cells carry out different types of responses: T<sub>H</sub>1 is responsible for enhancing the [[Macrophages|macrophage]] response, whereas T<sub>H</sub>2 cells enhance the [[Lymphocytes#B Cells|B cell]] antibody production, and T<sub>H</sub>17 cells enhance the innate immune response through increased granulocyte trafficking.  Typically, animals produce a balanced response of T<sub>H</sub> cells, though this can lead to pathology, as can a skewed response, depending on the nature of the foreign organism.  For more on [[Lymphocytes#T Cells|T cell]] differentiation, see [[T cell differentiation|here]].
    
*''[[Lymphocytes#B Cells|B cell]] response''
 
*''[[Lymphocytes#B Cells|B cell]] response''
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