Yes, anything that triggers your immune system to have a response would be considered an antigen. H1N1 is a virus that causes influenza, and the detection of the presence of t
…he virus will cause our immune systems to attack it. The immune system creates antibodies which can grab antigens to flag them as targets and disable them, which are then attacked and destroyed by other cells from the immune system. Once the body has developed antibodies to match the antigens of a particular invader , the pattern of those antibodies is stored by the immune system, and duplicates can be readily produced to grab that invader, if it or one like it, is detected again. That is what gives you immunity. (MORE) 
