BOSTON: Scientists have found evidence of lower-than-expected transfer of antibodies to protect against the new placental coronavirus from infected mothers in the third trimester, findings that shed light on critical windows during pregnancy that could be more desirable for vaccination.
According to researchers, including those at Massachusetts General Hospital (MGH) in the US, the findings can be explained by a process in which carbohydrate molecules in the body modify antibodies after they are produced.
They explained that modified carbohydrate attachments to coronavirus-specific antibodies – a process called glycosylation – may be to blame for reduced mother-to-child transfer.
In the study, published in the journal Cell, scientists compared maternal antibodies against the flu (flu), whooping cough (pertussis) and the new coronavirus – SARS-CoV-2 – and how these antibodies were transferred across the placenta.
They found that flu and pertussis-specific antibodies were actively transferred in a relatively normal manner.
In contrast, the researchers said that the transfer of specific SARS-CoV-2 antibodies to the child was not only significantly reduced, but the transferred antibodies were less functional than those against influenza.
According to scientists, the reduced transfer was observed only in the infection of the third trimester.
The study found that carbohydrate attachments to specific SARS-CoV-2 antibodies in the mother’s blood were different from those seen to flu-specific antibodies and pertussis.
Researchers believe that this pattern of carbohydrates may cause COVID-specific antibodies to be “blocked” in the maternal circulation, rather than being transferred across the placenta via placental antibody receptors.
However, the scientists said that some increases in the total number of maternal antibodies induced by viral infection have contributed to the partial overcoming of the problem and facilitate the transfer of functional antibodies from mother to fetus.
Greater placental expression of a receptor that attracts carbohydrate pattern on specific SARS-CoV-2 antibodies also helped the study.
Based on the analysis, the scientists said that some of the antibodies that transferred the best are also the most functional, activating the killer’s natural killer cells that could help the newborn fight the virus if exposed.
The researchers believe the findings have implications for the design of new SARS-CoV-2 vaccine candidates for pregnant women.
“Vaccine regimens capable of leading to high levels of COVID-specific antibodies with favored placental glycosylation patterns for selective fetal transfer may lead to better neonatal and infant protection,” said study co-author Andrea Edlow, a maternal drug. fetal specialist at Massachusetts General Hospital.
The scientists said the results of the study may indicate critical windows during pregnancy, which may be most desirable for vaccination, to optimize protection for both the mother and her baby.
According to researchers, including those at Massachusetts General Hospital (MGH) in the US, the findings can be explained by a process in which carbohydrate molecules in the body modify antibodies after they are produced.
They explained that modified carbohydrate attachments to coronavirus-specific antibodies – a process called glycosylation – may be to blame for reduced mother-to-child transfer.
In the study, published in the journal Cell, scientists compared maternal antibodies against the flu (flu), whooping cough (pertussis) and the new coronavirus – SARS-CoV-2 – and how these antibodies were transferred across the placenta.
They found that flu and pertussis-specific antibodies were actively transferred in a relatively normal manner.
In contrast, the researchers said that the transfer of specific SARS-CoV-2 antibodies to the child was not only significantly reduced, but the transferred antibodies were less functional than those against influenza.
According to scientists, the reduced transfer was observed only in the infection of the third trimester.
The study found that carbohydrate attachments to specific SARS-CoV-2 antibodies in the mother’s blood were different from those seen to flu-specific antibodies and pertussis.
Researchers believe that this pattern of carbohydrates may cause COVID-specific antibodies to be “blocked” in the maternal circulation, rather than being transferred across the placenta via placental antibody receptors.
However, the scientists said that some increases in the total number of maternal antibodies induced by viral infection have contributed to the partial overcoming of the problem and facilitate the transfer of functional antibodies from mother to fetus.
Greater placental expression of a receptor that attracts carbohydrate pattern on specific SARS-CoV-2 antibodies also helped the study.
Based on the analysis, the scientists said that some of the antibodies that transferred the best are also the most functional, activating the killer’s natural killer cells that could help the newborn fight the virus if exposed.
The researchers believe the findings have implications for the design of new SARS-CoV-2 vaccine candidates for pregnant women.
“Vaccine regimens capable of leading to high levels of COVID-specific antibodies with favored placental glycosylation patterns for selective fetal transfer may lead to better neonatal and infant protection,” said study co-author Andrea Edlow, a maternal drug. fetal specialist at Massachusetts General Hospital.
The scientists said the results of the study may indicate critical windows during pregnancy, which may be most desirable for vaccination, to optimize protection for both the mother and her baby.