T cells originate in the bone marrow and mature in the thymus. They are primarily divided into two types: Helper T cells (CD4+) and Cytotoxic T cells (CD8+). Helper T cells assist in activating other immune cells, while Cytotoxic T cells directly destroy infected or cancerous cells. T cells recognize antigens through their T-cell receptors (TCRs), which bind to peptide fragments presented by Major Histocompatibility Complex (MHC) molecules on the surface of antigen-presenting cells.
