About:

• Formally known as mRNA-1644, it is made in a way to stimulate the B cells of the immune system. These are a class of white blood cells that produce antibodies which can bind to invading bacteria and viruses.
  
  
• The larger purpose of stimulating the B cells is to generate what are called broadly neutralising antibodies (bnAbs), which are specialised blood proteins that attach to the surface proteins of HIV and disable them by accessing key but hard-to-reach regions on the virus.
  
  
• Over the last decade, there have been advances in identifying new bnAbs from HIV-infected individuals that were seen to target very specific sites in the outer envelope of the HIV.
  
  
• Lab-based analysis and tests on animals have improved the understanding of how the knowledge of these sites can be used to make immunogens (or parts of a virus or bacteria that elicit an antibody response from the immune system. In the case of a coronavirus, for instance, the spike protein is an immunogen against which different vaccines elicit antibodies.)
  
  
• One such immunogen that has been designed in the lab is eOD-GT8 60mer, developed by the International AIDS Vaccine Initiative (IAVI) and its partners.