National Geographic

Newborns Suppress Immune System to Let Gut Bacteria In

The womb is a (mostly) sterile environment. When babies leave it, they are thrust into a world that’s positively teeming with microbes—bacteria, viruses, fungi, parasites, and more. Some threaten to infect them and cause disease. Others are necessary for their survival and colonise their guts, skin and other organs.

Babies need to keep the dangerous microbes out, and let the beneficial ones in. It’s a tough balancing act, and one whose solution has only just been discovered.

Shokrollah Elahi from the Cincinnati Children’s Hospital Medical Center has found that newborn mice have special immune cells that suppress the rest of their immune system. This makes them unusually vulnerable to infections for the first two weeks of life, but it also gives other bacteria a chance to settle their guts.

Newborn humans are also especially vulnerable to infections for their first months of life, and most people believed that this was because our immune systems take a while to mature. But if Elahi is right, then this explanation if wrong. If the same suppressor cells exist in human infants, then our early window of vulnerability isn’t due to an immature immune system, but an actively suppressed one.

I’ve written more about this study at The Scientist, so head over there for the details.

There are 6 Comments. Add Yours.

  1. Mazi Ude
    November 12, 2013

    It is amazing that babies can suppress their immune system. One lesson for man is that bacteria is important for our survival.

  2. charlene knight
    November 12, 2013

    I wonder if the new cell he found could turn immunity on and off later if life. Maybe it does do that. If we could make it turn on more than maybe we could defeat cancer.

  3. Micaela Ramirez
    November 13, 2013

    When the baby enters the world, how come they cry? Are they in pain or adjusting the world? I have never understood that.

  4. Preston Garrison
    November 16, 2013

    The people developing oncolytic viruses are finding that it helps to be able to temporarily suppress the immune response when dosing with OVs – wonder if CD71+ cells could be of use.

  5. mj
    November 16, 2013

    Newborns first cry as a response to change in atmospheric pressure from whom to room air. Lungs expand as a result of exiting the whom, and independent respiration accompanied with crying occurs as a result. Its magical!

  6. Steve Stoltz
    November 16, 2013

    So, a baby’s immediate environment for its first two weeks may be critical to the establishment of its micro biome and might have a long-term possibly life time effects on health and development of the immune system?

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