Bacterial vesicles coated on gold nanoparticles to combat TB

Researchers from the Indian Institute of Science (IISc) have designed a new method to deliver a vaccine candidate for tuberculosis (TB). It involves using spherical vesicles secreted by bacteria coated on gold nanoparticles which can then be delivered to immune cells. This can potentially trigger an immune response and offer protection against the disease.

Caused by the bacterium Mycobacterium tuberculosis, TB kills over a million people worldwide every year. The only effective vaccine currently in use is the BCG vaccine. It contains a weakened form of the disease-causing bacterium. When injected into our bloodstream, it triggers the production of antibodies that can help fight the disease.

While the BCG vaccine works well in children, it is not as effective at protecting adolescents and adults. This prompted Rachit Agarwal, Assistant Professor at the Center for BioSystems Science and Engineering (BSSE), IISc, and his group to develop a potential subunit vaccine candidate that contains only parts of the infectious bacterium to stimulate an immune response.

Scientists have earlier developed subunit vaccines based on just a handful of proteins from the disease-causing bacteria, but none of them have been effective so far. Instead, Agarwal's group decided to use Outer Membrane Vesicles (OMVs). OMVs are spherical membrane-bound particles released by some bacteria, and contain an assortment of proteins and lipids which could induce an immune response against the pathogen.

Mycobacterium-derived OMVs are usually unstable and come in different sizes, making them unsuitable for vaccine applications. But the OMVs coated on gold nanoparticles (OMV-AuNPs) by the IISc team were found to be uniform in size and stable. The researchers also found that human immune cells showed a higher uptake of OMV-AuNPs than of OMVs or gold nanoparticles alone.

Zdroj obrázku: George et al. (2022), Biomaterials Advances.