Search

Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1-transmitting mothers and 165 propensity score-matched nontransmitting mothers were selected from the Women and Infants Transmission Study (WITS) of US nonbreastfeeding, HIV-1-infected mothers. In a multivariable logistic regression model, the magnitude of the maternal IgG responses specific for the third variable loop (V3) of the HIV-1 envelope was predictive of a reduced risk of MTCT. Neutralizing Ab responses against easy-to-neutralize (tier 1) HIV-1 strains also predicted a reduced risk of peripartum transmission in secondary analyses. Moreover, recombinant maternal V3-specific IgG mAbs mediated neutralization of autologous HIV-1 isolates. Thus, common V3-specific Ab responses in maternal plasma predicted a reduced risk of MTCT and mediated autologous virus neutralization, suggesting that boosting these maternal Ab responses may further reduce HIV-1 MTCT.

Background: Infant responses to vaccines can be impeded by maternal antibodies and immune system immaturity. It is therefore unclear whether human immunodeficiency virus type 1 (HIV-1) vaccination would elicit similar responses in adults and infants., Method: HIV-1 Env-specific antibody responses were evaluated in 2 completed pediatric vaccine trials. In the Pediatric AIDS Clinical Trials Group (PACTG) 230 protocol, infants were vaccinated with 4 doses of Chiron rgp120 with MF59 (n=48), VaxGen rgp120 with aluminum hydroxide (alum; n=49), or placebo (n=19) between 0 and 20 weeks of age. In PACTG 326, infants received 4 doses of ALVAC-HIV-1/AIDSVAX B/B with alum (n=9) or placebo (n=13) between 0 and 12 weeks of age., Results: By 52 weeks of age, the majority of maternally acquired antibodies had waned and vaccine Env-specific immunoglobulin G (IgG) responses in vaccinees were higher than in placebo recipients. Chiron vaccine recipients had higher and more-durable IgG responses than VaxGen vaccine recipients or ALVAC/AIDSVAX vaccinees, with vaccine-elicited IgG responses still detectable in 56% of recipients at 2 years of age. Remarkably, at peak immunogenicity, the concentration of anti-V1V2 IgG, a response associated with a reduced risk of HIV-1 acquisition in the RV144 adult vaccine trial, was 22-fold higher in Chiron vaccine recipients, compared with RV144 vaccinees., Conclusion: As exemplified by the Chiron vaccine regimen, vaccination of infants against HIV-1 can induce robust, durable Env-specific IgG responses, including anti-V1V2 IgG., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)