Nano-vaccines for HIV and malaria

Researchers at MIT have discovered packing vaccines into concentric fatty spheres could be key to designing safe vaccines for diseases like HIV and malaria

Pathogens like HIV like to stay inside cells, so vaccines need to evoke a strong immune response from killer T cells – cells which attack body cells infected with the pathogen. The best way to kick start these cells into action is to use a dead or disables virus – HIV however is difficult to render harmless.

While many scientists are working on a synthetic vaccine for HIV, Darrell Irvine – associate professor of material science and engineering and biological engineering at MIT – created vaccine-delivering nanoparticles by placing liposome spheres inside one another.

These liposomes can help promote T cells response by packaging the protein in a virus-like particle, but they aren’t very stable in the body. Irvine decided to put the droplets together in concentric spheres, making the structure more stable and less likely to break down following injection. They nanoparticles degrade once absorbed by a cell, releasing the vaccine and provoking a T cell response.

Together with colleague James Moon, Irvine used the nanoparticles to deliver ovalbumin – an egg-white protein used in immunology studies because it is easy to track the immune response to it – in mice. They found that three immunizations of low doses produced a strong T cell response, and after immunisation up to 30% of all killer T cells in the mice were specific to the vaccine protein.

Irvine said: “That is one of the strongest T cells responses generated by a protein vaccine, and comparable to strong viral vaccines, but without the safety concerns of live viruses.”

Irvine and his colleagues are now testing the nanoparticles’ ability to deliver an experimental vaccine in mice, and developing the nanoparticles to deliver cancer and HIV vaccines.