Level of maternal respiratory syncytial virus (RSV) F antibodies in hospitalized children and correlates of protection

Background

Respiratory syncytial virus (RSV) is a major cause of lower respiratory infection among children and no vaccine is available. The stabilized form of the fusion (F) protein – pre-F – is a leading vaccine candidate to target different populations, including pregnant women. This study aimed to determine the magnitude and nature of RSV-directed maternal antibodies (matAbs) in hospitalized children with RSV infection.

Methods

Sixty-five paired blood samples were collected from RSV-infected children aged <6 months and their corresponding mothers. All pairs were screened for levels of pre-F and post-F antibodies using ELISA. The neutralizing antibodies (NAbs) in both groups were measured in vitro against mKate RSV-A2 using H28 cells.

Results

It was found that 14% of matAbs (log2 12.8) were present in infants at hospitalization, with an average log2 EP titer of 10.2 directed to both F-protein conformations. Additionally, 61.4% of maternal NAbs (log2 EC50 = 9.4) were detected in infants (log2 EC50 = 8.7), which were mostly pre-F exclusive (81%). Pre-F antibodies in children showed a positive correlation with matAbs titers and negative correlations with age and bronchiolitis score.

Conclusions

The maintenance of neutralizing activity in infants relative to maternal titers was greater than the maintenance of antibody binding based on ELISA, suggesting that higher-potency antibodies may have a longer half-life than weakly neutralizing antibodies.

Other Information

Published in: International Journal of Infectious Diseases
License: http://creativecommons.org/licenses/by-nc-nd/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.ijid.2021.06.015