Pimping those T-cells
posted: 11/11/2008
Researchers have created souped-up T-cells which are far better at homing in on HIV than the natural "killer" T-cells our bodies produce.
Pimped up T-cells have a lab-made molecular receptor which gives the body an edge against a virus. It is based on one from someone whose immune system is far better than most people's at spotting and destroying HIV.
One reason HIV gets around our immune system defences, as well as around the drugs and vaccines, is the virus's quick-change artist behaviour – because it mutates so rapidly, HIV quickly changes its cloak and so evades attacks. But some parts of HIV are so vital to its functioning that changes result in dead or much less damaging viruses. The pimped T cells target one of these key bits of protein.
The virus normally keeps this hidden from our immune system. But when HIV infects cells, small bits of protein get trapped on the surface, acting as warning flags to the immune system. The problem with our natural killer T-cells is they are rubbish at spotting the protein – the pimped T-cells however home in on the target and then destroy the infected cell - thus preventing the virus from spreading.
The pimped T-cells have proved effective in laboratory tests using human cell cultures – it will now be tested in a USA clinical trial of 35 patients with advanced HIV infection that is due to start next summer.
One pitfall could be that the cells prove too strong for their own good, because there is a chance they could recognise and attack human proteins.
If this new appraoch works it will be some years before it is released generally. Treating patients will involve taking a blood sample and adding an engineered virus containing genes for the improved T cell receptor. The patient's own T cells then take up the genes and so are equipped with the improved receptor. These cells are then injected back into the patient. It's a method that depends on advanced medical facilities and money - it is not likely to be affordable or practical in the developing world.
Sources New Scientist Guardian
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