The T helper cell needs to acttivate the T cyctotoxic cell in order for the Tc cell to go do its work.
Once the TC cell is active it interacts with MHC-1 proteins on the surface of the infected host cell, this allows the Tc cell to recignise the host cell and begin secreting cytotoxins (perforins and granzymes) in order to degrade the infected cell and cause apoptosis (controlled cell death)
