The initiation of a cell-mediated immune response requires the binding of antigenic peptides to a host major histocompatibility complex (MHC) molecule.When this complex is successful,it will activate a specific T cell which multiplies to bring about an eventual resolution of the infection.If no stable complex occurs,the body will fail to recognize the foreign agent and no immune response will be mounted against that specific agent.Hence,understanding in detail the rules for successful MHC-peptide engagement may allow pharmaceutical manipulation of the host immune system.In this presentation,we will share our experiences in the modeling of MHC binding events and show how state-of-the-art computational algorithms can be used to facilitate the design of effective vaccines.