Types of cell T-Cells

1. CD4+ Cells (helper T cells): Bind to antigens presented by APC (macrophages, B-cells) via the MHC Class II (HLA-D)
   1. EXOGENOUS Ag
   2. Activates B cells to become plasma cells
   3. Inhibits intracellular bacteria, fungi, parasites
2. CD8+ Cells (CytotoxicT-cells): Bind to cells via the MHC Class I (HLA, B, C)
   1. ENDOGENOUS Ag
   2. Kills virus-infected cells and tumor cells