Scientists use tiny gold particles to develop vaccine for RSV

US scientists have developed a novel vaccination method that uses tiny gold particles to mimic a virus and carry specific proteins to the body’s immune cells.

The technique differs from the traditional approach of using dead or inactive viruses as a vaccine and was demonstrated in the lab using a specific protein that sits on the surface of the respiratory syncytial virus (RSV).

The results have been published in the journal Nanotechnology by a team of researchers from Vanderbilt University in Nashville, Tennessee.

RSV is the leading viral cause of lower respiration tract infections. The detrimental effects come, in part, from the F protein, which coats the surface of the virus. The protein enables the virus to enter into the cytoplasm of cells and also causes cells to stick together, making the virus harder to eliminate.

A vaccine for RSV, which is the major cause of viral pneumonia in children, is sorely needed

The body’s natural defence to RSV is therefore directed at the F protein; however, up until now, researchers have had difficulty creating a vaccine that delivers the F protein to the specialised immune cells in the body. If successful, the F protein could trigger an immune response, which the body could ‘remember’ if a subject became infected with the real virus.

In this study the researchers created tiny gold nanorods, just 21 nanometres wide and 57 nanometres long, which were almost exactly the same shape and size as the virus itself. The gold nanorods were successfully coated with the RSV F proteins and were bonded strongly thanks to their unique physical and chemical properties.

The researchers then tested the ability of the gold nanorods to deliver the F protein to specific immune cells, known as dendritic cells, which were taken from adult blood samples.

They analysed the proliferation of T cells as a proxy for an immune response and found that the protein-coated nanorods caused the T cells to proliferate significantly more than non-coated nanorods and just the F protein alone.

Professor James Crowe, lead author of the study, said: ‘A vaccine for RSV, which is the major cause of viral pneumonia in children, is sorely needed. This study shows that we have developed methods for putting RSV F protein into exceptionally small particles and presenting it to immune cells in a format that physically mimics the virus. Furthermore, the particles themselves are not infectious.’

Due to the versatility of the gold nanorods, Professor Crowe believes that their potential use is not limited to RSV. ‘This platform could be used to develop experimental vaccines for virtually any virus, and in fact other larger microbes such as bacteria and fungi,’ he said.

‘The studies we performed showed that the candidate vaccines stimulated human immune cells when they were interacted in the lab. The next steps to testing would be to test whether or not the vaccines work in vivo.’