Higher tumour killing power than T-cells
Amplified Natural Killer (ANK) cells have a higher tumour killing power than T cells. Although the number of T cells in the body is at least a trillion compared to only around 100 billion Natural Killer (NK) cells, Killer T cells only make up about 33% of T cells. They must also be primed by exposure to the same type of cancer cell beforehand to kill, unlike NK cells which recognise and kill all cancer cells indiscriminately, thus causing a slower response.
A comparison of the effect of ANK cell versus the cytotoxic Killer T cells on breast cancer cells, after 24 and 48 hours respectively. ANK cells are much more efficient and thorough in clearing out cancer cells.
Most importantly, Killer T cells are unable to recognise cancer cells that do not express MHC class I molecules. This means that only cancer cells which express MHC class I cells are killed; cancer cells which do not have MHC class I remain in the body undetected, which gives rise to recurrent cases. This, together with weaker killing power, severely limit their use and effect in immunotherapy.