In a groundbreaking study, researchers have discovered that pregnancy may actually enhance an immune defense against certain infections, challenging the conventional belief that expectant mothers face heightened vulnerability. The study, conducted on mice, revealed that pregnancy fortifies an immune response capable of blocking the Influenza A virus from advancing to the lungs, a site where it can cause severe and potentially fatal infections.
"Our results are surprising because of the current dogma, but it makes sense from an evolutionary perspective," explained Dr. Maziar Divangahi, co-lead author of the study and a professor in McGill University's Faculty of Medicine and Health Sciences. He also serves as a Senior Scientist at the Research Institute of the McGill University Health Centre (RI-MUHC). "A mother needs to stay healthy to protect her developing baby, so the immune system adapts to provide stronger defenses. This fascinating response in the nasal cavity is the body's way of adding an extra layer of protection, which turns on during pregnancy."
The researchers utilized a mouse model to examine how a specific immune cell is activated in the nasal cavity during pregnancy. This cell produces a potent molecule that significantly bolsters the body's antiviral defenses, particularly in the nose and upper respiratory tract.
"Influenza A virus remains among the deadliest threats to humanity," stated Julia Chronopoulos, the study's first author, who conducted the research as part of her PhD at McGill. "This natural immunity in pregnancy could change the way we think about flu protection for expectant mothers."
Currently, the Public Health Agency of Canada advises pregnant women and pregnant individuals to receive the influenza vaccine due to the high risk of severe illness and complications, including preterm birth. However, the insights from this study open up the possibility for more tailored vaccine strategies.
"The broader population could also benefit, as our findings suggest the immune response we observed could be replicated beyond pregnancy," said Dr. James Martin, co-lead author, who is also a Professor at McGill and Senior Scientist at the RI-MUHC. This could pave the way for the development of new nasal vaccines or treatments designed to enhance protective molecules known as Interleukin-17.
Looking ahead, the research team is shifting focus to strategies that could minimize lung damage during viral infections, such as influenza or COVID-19. Instead of targeting the virus itself, they aim to modulate the immune system's response to prevent excessive inflammation, which could, in turn, reduce the risk of serious flu-related complications.
The study was funded by the Canadian Institutes of Health Research, promising new avenues for both maternal and general health advancements.