Are COVID-19 Specific Antibodies Transferred To Newborn?

Recent data has shown that pregnant women and newborns may face increased risk of developing more severe cases of COVID-19 following SARS-CoV-2 infection. The research indicates lower than expected transfer of protective SARS-CoV-2 antibodies through the placenta from mothers who are infected in the third trimester. This can be due to changes in the antibodies after they are produced by a process called glycosylation. The study conducted by investigators at Massachusetts General Hospital (MGH) is published in the journal Cell.

An earlier study published in the JAMA Network Open found that pregnant women with COVID-19 infection do not pass SARS-CoV-2 virus but passes on relatively low levels of antibodies against it to newborns.

For this study scientists compared maternal antibodies against the whooping cough (pertussis), flu (influenza), and SARS-CoV-2, and how these antibodies are transferred across the placenta. Antibodies specific to influenza and whooping cough was actively transferred by a normal mechanism. However the transfer of SARS-CoV-2-specific antibodies to the baby was significantly reduced and the antibodies transferred were less functionally active than the antibodies against influenza. This reduced transfer was seen only during the third trimester.

This reduced transfer of antibodies from mother to fetus is due to the changes in the attachments of carbohydrates to the SARS-CoV-2-specific antibodies, a process called glycosylation which was different those seen on influenza- and pertussis-specific antibody.

This change in carbohydrate attachment can cause the COVID-19 specific antibodies to be ‘stuck’ in the maternal circulation instead of getting transferred across the placenta via placental antibody receptors. Some of the antibodies that were transferred from mother to the fetus were the most functional and activated natural killer cells that could help the newborn fight the virus if exposed.

These findings can impact the design of vaccines against SARS-CoV-2 for pregnant women.

Co-senior author Andrea Edlow, MD, MSc, a maternal-fetal medicine specialist at MGH and an assistant professor of Obstetrics, Gynecology, and Reproductive Biology at Harvard Medical School said, Vaccine regimens able to drive high levels of the COVID-specific antibodies with glycosylation patterns favored by the placenta for selective transfer to the fetus may lead to better neonatal and infant protection. We are beginning to define the rules of placental antibody transfer of SARS-CoV-2 for the very first time -- catalyzing our ability to rationally design vaccines to protect pregnant women and their newborns."

The understanding of how antibody transfer varies by trimester can help determine the critical windows in pregnancy that may be most desirable for vaccination to optimize protection for both the mother and her infant.

Source-Medindia