Remember, MHC is the major histocompatibility complex that our cells use to basically differentiate healthy cells from our infected cells. And once the pathogenic antigen is found on the MHC class one complex, some type of white blood cell, a macrophage, a neutrophil, or our cytotoxic T cell, a special type of T lymphocytes, can basically approach this infected cell. And if it contains the specific type of antibody that reflects this specific type of antigen, they can basically bind. And then the cytotoxic T cell can release powerful proteins that ultimately poke holes in this cell and lies the cell, killing that cell off. And then a macrophage can swim by and pick up the remaining debris from that infected cell. So, mechanism number three, we can also actually have a process known as Aglutination.