What is the difference between CD4 and CD8 T cells?

CD4 cells, also known as helper T-cells, trigger the immune response by recognizing pathogens and secreting cytokines in order to signal to other immune cells, including CD8 cells. CD4 cells are not directly responsible for the attack of the pathogens; on the other hand, CD8 cells, known as the cytotoxic T-cells, destroy the infected cells.