Now the signal the attack to stop. Helper T-cells Suppressor T-cells B-cells Killer T-cells Question 13 1 pts Cell-mediated immunity involves T-cells, and the Major Histocompatibility Complex (MHC). The MHC aids in the replication of T-cells disguises antigens to protect them from Killer Tcells signals interleukins to begin their work allows the immune system to tell its own cells apart from invading cells.