 Higher MHC I expression leads to higher presentation of viral and abnormal peptides from cancer cells to cytotoxic T cells, while the immunoproteasome more efficiently processes these peptides for loading onto the MHC I molecule.Therefore, the recognition and killing of infected or malignant cells increases.Higher MHC II expression enhances presentation of viral and cancer peptides to helper T cells; which are releasing cytokines (such as more interferons, interleukins and other cytokins) that stimulate and co-ordinate the activity of other immune cells.