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→Introduction
Naive T-cells have yet to encounter antigen and can only be activated by antigen presented by dendritic cells. After initial antigenic activation, naïve T-cells develop into an intermediate stage cell called the TH<sub>0</sub> cell which can then be activated by any antigen-presenting cell, e.g. Dendritic cell, macrophage or B-cell.
Naive T-cells have yet to encounter antigen and can only be activated by antigen presented by dendritic cells. After initial antigenic activation, naïve T-cells develop into an intermediate stage cell called the TH<sub>0</sub> cell which can then be activated by any antigen-presenting cell, e.g. Dendritic cell, macrophage or B-cell.
The TH<sub>0</sub> cells have the capacity to differentiate into TH<sub>1</sub> and TH<sub>2</sub> cells. The type of cell that develops depends on the antigen presenting cell. Macrophages cause the TH<sub>0</sub> cell to develop into TH<sub>1</sub> cells caused by IL-12 production following macrophage-antigen interaction. B-cells cause the TH<sub>0</sub> cell to develop into TH<sub>2</sub> cells caused by IL-10 production following B-cell-antigen interaction, on antigenic stimulation the TH<sub>1</sub> or TH<sub>2</sub> cells become activated, undergo clonal expansion and secrete a range of different cytokines.
The TH<sub>0</sub> cells have the capacity to differentiate into TH<sub>1</sub> and TH<sub>2</sub> cells. The type of cell that develops depends on the antigen presenting cell. Macrophages cause the TH<sub>0</sub> cell to develop into TH<sub>1</sub> cells caused by IL-12 production following macrophage-antigen interaction. B-cells cause the TH<sub>0</sub> cell to develop into TH<sub>2</sub> cells caused by IL-10 production following B-cell-antigen interaction. On antigenic stimulation the TH<sub>1</sub> or TH<sub>2</sub> cells become activated, undergo clonal expansion and secrete a range of different cytokines.
For any one cell the cytokine-secreting activation state is short-lived, lasting between 4 - 40 hours. After this time these cells either die, or mature into the long-lived memory cells. The proliferation of T cells continues until antigen disappears.
For any one cell the cytokine-secreting activation state is short-lived, lasting between 4 - 40 hours. After this time these cells either die, or mature into the long-lived memory cells. The proliferation of T cells continues until antigen disappears.