Biodegradable 'cells' boost immune system

Scientists from Yale have shown that the artificial cells promote a 45-fold increase in T-cells which can then target tumours, and it is thought the technique will be easily adaptable for wide-spread clinical use. When treating cancer using adaptive immunotherapy, doctors harvest T-cells from the patient's blood and present them with artificial cells carrying antigens specific to the disease they are treating. The presence of these antigens stimulate the T-cells into replicating to produce more and more T-cells that will attack the tumour, which are then be fed back into the patient's blood. Previous attempts at producing these artificial cells have included magnetic beads coated with antigens which can be easily filtered from the mixture before it is injected back into the patient. However, this form of immunotherapy is most effective when a certain proteins - called cytokines - are present, which stimulate a far greater proliferation of T-cells. The previous artificial cells could not carry the cytokines themselves, so the whole mixture had to be bathed in these proteins - a procedure that did not mimic the natural immune system and possibly limited the efficacy of the treatment. The new cells, however, are made from very long polymers usually found in medical stitches, wrapped around bundles of the cytokines and coated in universal adaptor molecules that bind to antigens and stimulatory molecules. "This 'biodegradable yarn ball' breaks up and releases the cytokines when it meets water​," Tarek Fahmy, who also worked on the project, told LabTechnologist.com. The encapsulated cytokines are released very slowly over time, as the T-cells are being stimulated by the antigens, which is thought be much closer to the natural immune system. "These enhancements mimic the natural binding and signalling events that lead to T-cell proliferation in the body​," says Erin Steenblock, lead author of the paper. The result was a 45-fold increase in T-cells compared to a 20-fold increase using other methods. In addition, previous methods had produced a mixture of the different types of T-cells, many of which are not effective at treating cancer. Steenblock's method, however, created a mixture with roughly 90 per cent "cytotoxic" or killer T-cells that directly attack the tumour. "It's much more potent if the cytokines are released in close proximity to the stimulation​," said Fahmy. It is hoped the cells will also be more practical for the clinical application. "It's a very nice way of preserving cytokines for long-term storage before use​," said Fahmy. "It's a powder that could be distributed very easily to different places, so it could allow the treatment to become more widespread." ​Because the cells are made from biodegradable materials that are already in clinical use, it is hoped that the treatment could hit hospitals very soon. In the future the team hope to investigate the possibility of applying the cells in-vivo, rather than externally, which would ease the procedure and hopefully lead to more widespread usage.