The are 3 main parts of our immune system.  When we do research we're looking for things to boost the first part.  The first part is called innate immune system.  That's the part we're born with.  The innate immune system heals broken bones.  It also fights bacteria and viruses.  The other 2 parts of your immune system is precise and specific.  You cure diseases with it.  This part is ignored in medical training and research.