What are two defences the body has against swine flu?

yes the white blood cells(helper-T cells) are the ones that swallow up the virus, also once the body has fought off the virus the (memory cells) keep a memory of that virus so once it invades your body again it can fight if off quickly without you getting ill. some viruses don't mutate like polio and chicken pox so you can only can them once. But common colds and influenza mutate rapidly so you can catch them over and over again.