Previously I discussed the relation of the human microbiome to malnutrition. Furthermore, in the previously discussed study, the twin that developed kwashiorkor had an underdeveloped microbiome for their age (3 years). Microbiomes, like many parts of our body, continue to grow and develop as we age. So, how does this developmental process of the microbiome? Well, although babies are born with personal assortment of microbes recieved from their mom, it takes a couple of years for the micrbiome to fully form. A recent study suggests that the immune system of babies are actively suppressed in order to further develop this microbiome (Elahi, et al, 2013). Previously, the lack of immune defense in infants has believed to have been related to immature immune cells. Nevertheless, this particular study found another possible explanation. Researchers discovered that blood cells found in infant umbilical cords (called CD71 cells) actually act as an immunosuppressive. Researchers hypothesized that perhaps the purpose of CD71 cells is to combat the natural inflammation that would occur upon abrupt colonization of bacteria. Furthermore, by suppressing the immune system, babies could catch good microbes (along with the cold-inducing microbes) (Elahi, et al, 2013). However, this study did not investigate the amount of time babies have a suppressed immune system; but it's speculated that the immune system would strike a balance a couple of years after birth.
Who knew being sick had its benefits?
Reference:
Elahi, S., Shaaban, A. F., Kinder, J. M., Ertelt, J. M., Way, S. S., Kalfa, T. A., et al. (2013). Immunosuppressive CD71+ erythroid cells compromise neonatal host defence against infection. Nature, 504(7478), 158-162. Retrieved May 16, 2014, from http://dx.doi.org/10.1038/nature12675
A thought-provoking title! I’ve heard that children living in high-rise buildings tend to be more sickly than children from suburban areas, and they also have a much smaller gut microbial community. It has been postulated that this is likely due to “apartment” children not playing as much outside and picking up microbes there. I am curious about one aspect of Elahi et al.’s (2013) study. While it is all very well and good to pick up good microbes, surely suppressing the immune system results in heightened risk of picking up potentially lethal microbes/pathogens? Can CD71 cells be “switched off” to prevent this from occurring? Nice.
ReplyDeleteThe article didn't mention whether or not CD71 cells could be 'switched off'. However, eventually children stop suffering from high susceptibility to illnesses; so perhaps this could be an explanation in their ability to strike an immune balance and fight off more of those bad microbes. It may be that once the immune system has a sufficient amount of 'good microbes', the CD71 cells switch off to preserve that environment.
ReplyDeleteThat's really interesting that children living in apartments tend to have a different gut microbial community! It's astonishing to think environment can affect those creatures living in your gut. It makes sense that the children would have less outside exposure and consequently loose the opportunity to contact a wide array of microbes. Perhaps this is a further benefit of children satisfying their curiosity with taste- more good microbes (and bad ones as well).