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Vaccine-specific immune responses in HIV-exposed uninfected infants

University of British Columbia

The advent of antiretroviral (ARV) therapy has resulted in a steep decline in mother-to-child transmission of HIV and a corresponding increase in infants who are born HIV-exposed but uninfected (HEU). There is ample evidence to suggest that infants who have been vertically exposed to HIV are at higher risk of infectious morbidity and mortality. The cause of this increased risk remains unknown and is likely due to multiple factors, one of which may be deficiencies in immune development resulting from in utero exposure to HIV and /or antiretrovirals. The purpose of this study was to interrogate the adaptive immune response in HIV-exposed, uninfected infants to determine if they differ in a significant way from their unexposed (UE) counterparts. We assembled a cohort of HEU infants and UE control infants in Cape Town, South Africa between 2008-2011 and compared their humoral and cell-mediated immune responses to the Hepatitis B virus vaccine. The results presented here reveal that HEU infants develop a robust humoral response to vaccination that does not considerably differ from that of UE infants. We also determined that in both arms of the cohort, the cellular response to HBV vaccination was primarily Th2-biased, as measured by levels of plasma IL-5 and IL-13. This response was significantly greater in UE infants at 6 months but not 12 months of age. HBsAg stimulation did not induce a strong Th1 response in either group of infants, as assessed by secretion of IFNγ and TNFα. We concluded that HEU infants have a well-developed response to the HBV vaccine that provides sufficient immunity and differs only transiently from that of UE infants.

Text

2020-08-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/75768

Experimental Medicine

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/