Pregnant women produce “superantibodies” to protect their newborns, and now scientists have discovered how they do it, which could open the door to improved treatments against deadly infections.
The study, which describes “a subtle” molecular change that allows the body’s most common antibody to assume an expanded protective role, is published in the journal Nature and is led by Cincinnati Children’s Hospital Medical Center (Ohio, United States).
Scientists discovered years ago that newborns depend on immune components transferred from their mothers to survive pathogens that begin to invade their bodies as soon as they are born.
Over time, a hospital statement describes, children develop their own immune systems, built through surviving natural exposures to viruses and bacteria, and augmented by a well-established set of childhood vaccines.
But in the meantime, it’s one of mothers’ most important gifts that keeps their babies safe: antibodies.
Now, this study offers a “striking” explanation of how those early days of maternally provided immunity actually work, and what that information could mean for preventing mortality and disability from a wide range of infectious diseases.
The results suggest that the boosted antibodies produced by pregnant mothers could be mimicked to create new drugs to treat diseases, as well as improved vaccines to prevent them.
The findings show that pregnancy changes the structure of certain sugars attached to antibodies, allowing them to protect babies from infection, explains Sing Sing Way.
The new study identifies which specific sugar changes during pregnancy and how and when the change occurs; specifically, there is a change (the loss of an acetyl group) in sialic acid, one of the sugars attached to antibodies.
This “very subtle” molecular change allows immunoglobulin G (IgG) – the body’s most common type of antibody – to take on an expanded protective role by stimulating immunity through receptors that respond specifically to modified sugars.
“This switch is the switch that allows maternal antibodies to protect babies from infection inside the cells,” says Way. “Mothers always seem to know better,” adds John Erickson, another of the authors.
This discovery paves the way for new “pioneer therapies” that can specifically target infections in pregnant women and newborn babies.
“I think these findings will have far-reaching implications for antibody-based therapies in other fields as well,” adds Erickson.
In this sense, Way affirms that the molecular alteration of antibodies that occurs naturally during pregnancy can be reproduced to change the way in which antibodies stimulate the immune system, and fine-tune their effects.
This could lead, he says, to improved treatments for infections caused by other intracellular pathogens, such as HIV and respiratory syncytial virus, a common virus that sometimes poses serious risks to babies.
In addition, the findings underscore the importance of women of reproductive age receiving all available vaccines, as well as the need for researchers to further develop vaccines against infections that are especially prominent in women during pregnancy or in newborns. .
“The immunity has to exist within the mother for it to be transferred to her child,” Way concludes.