breastinflation

Once they could be studied, it was found that the little machines Irene had been infected with were keyed only to her DNA and inside anyone else they stopped replicating after a few generations.  Without pumping out the helium, those infected will inflate almost as big as Irene does, though after a while they will deflate when the nanites cease to funtion.  A pump will aid in deflation or control the inflation.  To operate, the nanites require a lot of energy which they get from consuming adipose so those who are repeatedly exposed tend to slim down very nicely.