and then kill again. These are cytotoxic T cells a specialised member of our

white blood cells. They patrol our bodies identifying and destroying virally

infected and cancer cells and they do so with remarkable precision and efficiency.

There are about five million T Cells and a teaspoon of our blood engaged in the

ferocious and unrelenting battle to keep us healthy.

These amorphous blobs move around quite rapidly pushing out there leading

edge and probing their environment as they go.

When a cytotoxic T cell finds a cancer cell, membrane protrusions rapidly

explore the surface of the cell,

checking for the tell-tale signs of cancer. They kill their targets using

poisonous proteins visible here in red

these cytotoxic granules move down special pathways in the cell

called microtubules to the interface between the T Cell in the cancer cell.

The T cell punctures the surface of the cancer cell and delivers its deadly

cytotoxins. This is very important in our bodies where cells are packed together

as it focuses the lethal hit on the target and minimizes collateral damage

to the neighbouring healthy cells.

The fate of the cancer cell is sealed. The T cell then moves on hungry to find

another victim.