Binds the antigen.
T Cell Selection
Occurs in the Thymus.
Very few cells actually "graduate" the thymus. TCRs that can't interact with self MHC molecules are destroyed, and TCRs that are too attracted to self MHC are destroyed.
Subsets of CD4 T Cells
TH1 - Intracellular microorganisms
TH2 - Parasitic infections
TH17 - Extracellular bacteria and fungi
Treg - Tolerance
Important for stimulating macrophages and stimulating antibody production.
Important for the ingestion and killing of INTRAcellular microbes.
Stimulates the production of IgE antibodies as well as activating eosinophils.
Helpful for fighting helminth parasites.
Capable of recruiting neutrophils and causing inflammation. Also are implicated for their role in autoimmune diseases.
Learned in Thymus.
When mature T cells recognize self-antigens in peripheral tissues (that weren't in the Thymus). Inactivation of the cell occurs normally.
The loss of immunological tolerance.