The Major Histocompatibility Complex (MHC) serves three main functions: 

• The main function of the Major Histocompatibility Complex involves self-recognition. T lymphocytes or T cells are unable to recognize a potential threat to the body. MHC molecules play a key role in helping T cells recognize and bind to the body’s own cells (self-recognition) while identifying foreign antigens and signaling an immune response to destroy the invader. 
• The MHC directs T cells to destroy foreign invaders in the body. Depending on the type of foreign element, MHC molecules bind to it and then signal the T lymphocytes to eliminate it, leading to its destruction.
• MHC molecules often bind to peptide epitopes, forming ligands for T cell receptors (TCRs). These ligands assist in the recognition and targeting of tissues. After the cell is broken down, these ligands also play a role in restoring the cell’s structure to its original form.