Scientists have shown how some cells in the body can repel attacks from HIV by starving the virus of the building blocks of life.
Viruses cannot replicate on their own; they must hijack other cells and turn them into virus production factories.
A study, published in Nature Immunology, showed how some parts of the immune system destroy their own raw materials, stopping HIV.
It is uncertain whether this could be used in therapy, experts caution.
HIV attacks the immune system and can weaken the body's defences to the point that everyday infections become fatal.
However, not all parts of the immune system become subverted to the virus' cause. Macrophages and dendritic cells, which have important roles in orchestrating the immune response, seem to be more resistant.