http://www.bbc.co.uk/science/0/22028517 Viruses http://www.bbc.co.uk/science/0/22028517 response http://www.bbc.co.uk/science/0/22028517 http://www.bbc.co.uk/science/0/22028517 BBC: Flu http://www.bbc.co.uk/science/0/22028517 иммунную защиту fight