Cytotoxic T cells (Tc) kill abnormal cells and cells that are infected with pathogens.Abnormal cells have abnormal antigens on the cell surface and infected cells will have become antigen-presenting cells and present fragments of foreign proteins on the cell surface.Cytotoxic T cells produce proteins called perforins which make holes in the cell surface membrane.The cell membrane becomes freely permeable to all substances and the cell dies as a result.The action of cytotoxic T cells is effective against viruses that replicate inside of cells. The cell is effectively sacrificed to prevent viruses from multiplying and infecting other cells.