Our bodies get a disease by breathing in or eating some microbe or virus via mouth, nose or stomach. It has to then get to our blood stream but it first gets analyzed by our immune system and antibodies keyed to our body are created and when the virus hits our bloodstream, our immune response already has started to respond and attack it. Then when the virus has been eradicated from our body the specific antibody’s dna or structure is stored in our dna so when or if we get infected again, our body can easily and quickly create new antibodies to attack the virus.