| Basis of differentiation | T helper cells | T cytotoxic cells |
Definition | Are a type of immune cell that plays a supportive role in the immune system by recognizing foreign antigens and secreting cytokines that activate T and B cells | Are a type of immune cell that is capable of directly killing certain cells including tumor cells and virus infected cells directly by destroying the cell membranes |
Types of T cell receptor (TCR) on cell membrane | CD4 receptors | CD8 receptors |
Antigen presentation | Dendritic cells, macrophages, and neutrophils | Virus-infected cells and tumor cells |
Major Histocompatibility Complex (MHC) molecules | CD4 receptors present on the cell membrane can recognize antigens presented with MHC class II molecules | CD8 receptors present on the cell membrane can recognize antigens presented with MHC class I molecules |
Has the ability to kill pathogen directly | No | Yes |
Role | Secretion of cytokines that help to regulate other cells in the immune system and present antigens to the B cells | Directly destroy virus-infected cells and tumor cells |