Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water.  AFPs bind to small ice crystals to inhibit the growth and recrystallization of ice that would otherwise be fatal.  There is also increasing evidence that AFPs interact with mammalian cell membranes to protect them from cold damage.  This work suggests the involvement of AFPs in cold acclimatization.