Download Jeannie Taylor Microbiology Due: 11/15/2013 Assignment #7

Jeannie Taylor
Microbiology
Due: 11/15/2013
Assignment #7
Babies’ Weak Immune Systems Let in Good Bacteria
During a pregnancy, the baby that is in the womb is in a sterile environment. However, when the
baby is being born and has to travel down the birth canal, bacteria and fungi begin their
colonization. It is unknown how the immune system adapts so quickly to the change in
environments. A pediatrician at Cincinnati Children’s Hospital named Sing Sing Way went out
to find the answer to that question. Him and his colleagues compared immune cells in six-dayold mice with those of adult mice. He found that the baby mice had a much higher volume of red
blood cells that expressed a protein called CD71+. These cells suppress the immune response by
making an enzyme called arginase. Way and his colleagues then gave the baby mice antibodies
that caused the immune system to destroy the CD71+ cells and remove them form the animals’
blood. These mice were then infected after with the bacterium called Listeria monocytogenes.
This bacterium can cause severe infections in newborn humans. However, the animals that were
being tested did not show any severe reaction to this bacterium. Instead the immune system ward
off the attack. A problem that arose with this finding is after the CD71+ was taken out of the
mice’s’ systems, their intestinal cells became inflamed when they came across normal intestinal
bacteria. Another pediatrician at Boston Children’s Hospital in Massachusetts states that the
inflammation must be the body’s main logic for initially suppressing immunity. There are still a
lot of things that need to be figured and sorted out especially with the change in microbial
ecosystem that is intertwined with immune system making it difficult to alter one system without
disrupting the other. Way is trying to find a way to strengthen the babies immune systems by
temporarily reducing the number of CD71+ cells which in turn may enable health care workers
to vaccinate infant immediately. This idea is still a work in progress but they are making
significant steps.
http://www.scientificamerican.com/article.cfm?id=babies-weak-immune-system-let-goodbacteria-in