Context

A team of scientists from the Indian Institute of Science (IISc) has developed a new method to deliver a vaccine candidate for Tuberculosis (TB). 

About

The new method

• This new method involves using spherical vesicles secreted by bacteria coated on gold nanoparticles which can then be delivered to immune cells.
• This method is claimed to potentially trigger an immune response and offer protection against the disease.

Outer Membrane Vesicles (OMVs)

• 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, the new 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.
• To synthesise OMV-AuNPs, the OMVs and the gold nanoparticles are forced together through a 100 nm filter.
• The OMVs break up in the process and encapsulate the gold nanoparticles.