Scientists have found evidence of a lower-than-expected movement of novel antibodies against the coronavirus through the placenta from infected mothers in the third trimester, conclusions that throw light on emergency windows in a pregnancy that may be eligible for vaccination.
According to the researchers, including those from Massachusetts General Hospital (MGH) in the US, the findings can be explained by a process in which the carbohydrate molecules in the body change antibodies after for them to be taken out.
They explained that the reduced migration from mother to fetus may be due to altered carbohydrate binding to the specific antibodies coronavirus – a process called glycosylation.
In the study, published in the journal Cell, the scientists compared maternal antibodies against influenza (flu), whooping cough (pertussis), and the novel coronavirus – SARS-CoV-2 – and how these antibodies moved across the placenta.
They found that flu-specific antibodies and pertussis were actively mobilized in a very conventional fashion.
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In contrast, the researchers reported that not only was the transmission of SARS-CoV-2-specific antibodies to the child significantly reduced, but the antibodies transfused were less functional than those of antidepressants. the flu.
According to the scientists, the reduced movement was observed only in the third trimester disease.
The study found that carbohydrate binding to SARS-CoV-2 specific antibodies in maternal blood was different than those seen on influenza and pertussis specific antibodies.
The researchers believe that this carbohydrate pattern may cause the specific Covid antibodies to be “stuck” in maternal circulation, rather than being transmitted over the placenta through placental antibody receptors.
However, the scientists said that some increase in total maternal antibodies caused by viral infection helped to overcome the problem to some extent and enabled the transfer of some active antibodies from the mother. to fetus.
Higher placental analysis of receptors that attract a carbohydrate pattern helped the specific antibodies SARS-CoV-2, the study noted.
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Based on the analysis, the scientists said that some of the antibodies that move the best ones are also the most active ones, activating the natural killing cells of the immune system that may help the new baby to develop. fight off the virus if it is exposed.
The researchers believe the findings have an impact on the design of new vaccine candidates against SARS-CoV-2 for pregnant women.
“Vaccine management capable of driving high levels of Covid-specific antibodies with placenta-preferred glycosylation patterns for selective transfer to the fetus may lead to better neonatal and infant protection,” said study co-author Andrea Edlow, a maternal-fetal medicine specialist at Massachusetts General Hospital.
The scientists said the results of the study may indicate critical windows in pregnancy that may be eligible for vaccination to give the best protection for a mother and her baby.