Scientists think they may have identified a cell–transforming growth factor beta or TGF-B–which gives out signals that inhibit cell communication 
needed to produce natural killer cells in babies. Hence, babies possess a weak immune system during their formative years. Absence of this TGF-B signaling in infant mice led to growth of NK cells in mice at an accelerated rate.
So what does this mean? Are researchers going to try to create a drug or vaccine that will block that TGF-B signaling and jump start NK cell production in babies? I’m not sure what to think bout that. Nature outfits babies with weak immunity for a reason. My layman’s hypothesis is that exposure to basic microbes during infancy–which science has shown can “train” immune cells to grow, remember and respond at a “balanced,” appropriate level as a child matures–is nature’s preferred way of developing a functional immune system. That is, barring any extenuating condition that would abnormally stunt immune development. This is the “hygiene hypothesis.”
I like nature’s way as opposed to jumping onto another drug bandwagon.
