| Function | Cell |
| Migrate through tissues and phagocytose microbes | |
| Unknown, involved in hypersensity reactions | |
| Combat parasitic infection | |
| Carry oxygen to tissues | |
| Produce antibody or 'remember' infections | |
| Destroy virally infected cells and tumour cells or help other cells | |
| Destroy virally infected cells and tumour cells without a specific antigen | |
| Move to infection sites and differentiate in the tissue | |
| Form blood clots | |