Changes

===Response to Activation===

===Response to Activation===

The response of the T cells to obtaining Signals 1 and 2 is to express the receptor for the cytokine interleukin-2 (IL-2) and CD4⁺ T-cells secrete IL-2.  

The response of the T cells to obtaining Signals 1 and 2 is to express the receptor for the cytokine interleukin-2 (IL-2) and CD4⁺ T-cells secrete IL-2.  

The final trigger for clonal expansion is the engagement of IL-2R with IL-2 from any activated CD4+ T-cell. IL-2 produced by a CD4⁺ cell may also stimulate clonal expansion of the CD4⁺ cell.

The final trigger for clonal expansion is the engagement of IL-2R with IL-2 from any activated CD4⁺ T-cell. IL-2 produced by a CD4⁺ cell may also stimulate clonal expansion of the CD4⁺ cell.

==T-Helper Cell Function==

==T-Helper Cell Function==