Longitudinal development of antibodies to childhood vaccines and influenza during the first year of life
2Seattle Children's Research Institute, University of Washington
3Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town
Introduction
Infant immunity is underdeveloped, making them vulnerable to infections in early life. They receive maternal IgG via transplacental transfer during pregnancy, with efficiency increasing in the third trimester. After birth, maternal antibodies decline within 6–12 months, and breast milk provides additional sIgA and IgG. While maternal antibodies are protective against pathogens, they can also interfere with vaccine responses in newborns. Infants born to mothers with HIV - HIV-exposed uninfected infants (HEUI) - are more susceptible to infections early in life as compared to babies born to HIV uninfected mothers (HUI). Gaps remain in understanding the longitudinal development of infant immune repertoires, particularly IgA responses, necessitating further study.
Materials and methods
We used two mother-infant cohorts from South Africa: 36 dyads collected between 2014-2015 and 79 dyads collected between 2014-2018. Venous and cord blood samples were collected at birth and during the first year of life at five timepoints for infants, and at birth and 12 months for mothers. HEUI accounted for 40% and 50% of the cohorts, respectively. We used a high-throughput systems-serology assay based on antigen microarrays to profile IgG and IgA responses to common childhood vaccines, respiratory viruses and herpes viruses as well as an influenza specific antigen microarray.
Results and discussion
Infant maternal antibodies were undetectable for many respiratory viruses by week 15. We observed significant rises in IgG and IgA antibodies against vaccine antigens post vaccination. IgA rises were overall slower and sometimes delayed. We found serological evidence of primary infections for influenza B in cohort one and seasonal coronaviruses in the second cohort. Anti-viral titers were also observed for many other respiratory viruses by week 52. While antibody transfer rations of HUI were >1 for some viruses they were
Conclusions
Our study underscores the impact of maternal antibody transfer and early-life exposures on infant immunity, highlighting differences between HEUI and HUI groups. These findings reveal the dynamic interplay of maternal antibodies, vaccination, and infections in shaping immune development during the first year of life.