Viruses can have their own immune system...

[PhoenixBurger]

http://www.sci-news.com/biology/article00905.html

A new research led by Dr Kimberley Seed from the Tufts University School of Medicine provides the first evidence that bacteriophages – viruses that infect and replicate within bacteria – can acquire a wholly functional and adaptive immune system.

 

[snowathlete]

Thanks PhoenixBurder, thats really interesting. Bacteriophages, prophages, phage therapy...all very interesting stuff.