Impaired Haemophilus influenzae Type b Transplacental Antibody Transmission and Declining Antibody Avidity through the First Year of Life Represent Potential Vulnerabilities for HIV-Exposed but -Uninfected Infants
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Date
2014
Journal Title
Journal ISSN
Volume Title
Publisher
Clinical and Vaccine Immunology
Abstract
To determine whether immune function is impaired among HIV-exposed but -uninfected (HEU) infants born to HIV-infected
mothers and to identify potential vulnerabilities to vaccine-preventable infection, we characterized the mother-to-infant placen-
tal transfer of Haemophilus influenzae type b-specific IgG (Hib-IgG) and its levels and avidity after vaccination in Ugandan HEU
infants and in HIV-unexposed U.S. infants. Hib-IgG was measured by enzyme-linked immunosorbent assay in 57 Ugandan HIV-
infected mothers prenatally and in their vaccinated HEU infants and 14 HIV-unexposed U.S. infants at birth and 12, 24, and 48
weeks of age. Antibody avidity at birth and 48 weeks of age was determined with 1 M ammonium thiocyanate. A median of 43%
of maternal Hib-IgG was transferred to HEU infants. Although its level was lower in HEU infants than in U.S. infants at birth
(P < 0.001), Hib-IgG was present at protective levels (>1.0 -
g/ml) at birth in 90% of HEU infants and all U.S. infants. HEU in-
fants had robust Hib-IgG responses to a primary vaccination. Although Hib-IgG levels declined from 24 to 48 weeks of age in
HEU infants, they were higher than those in U.S. infants (P 0.002). Antibody avidity, comparable at birth, declined by 48
weeks of age in both populations. Early vaccination of HEU infants may limit an initial vulnerability to Hib disease resulting
from impaired transplacental antibody transfer. While initial Hib vaccine responses appeared adequate, the confluence of lower
antibody avidity and declining Hib-IgG levels in HEU infants by 12 months support Hib booster vaccination at 1 year. Potential
immunologic impairments of HEU infants should be considered in the development of vaccine platforms for populations with
high maternal HIV prevalence.
Description
Keywords
Impaired Haemophilus influenzae, Transplacental Antibody Transmission, HIV, Uninfected Infants
Citation
Gaensbauer, J. T., Rakhola, J. T., Onyango-Makumbi, C., Mubiru, M., Westcott, J. E., Krebs, N. F., ... & Janoff, E. N. (2014). Impaired haemophilus influenzae type b transplacental antibody transmission and declining antibody avidity through the first year of life represent potential vulnerabilities for HIV-exposed but-uninfected infants. Clinical and Vaccine Immunology, 21(12), 1661-1667.Clinical and Vaccine Immunology