Contrasting Adult and Infant Immune Responses to HIV Infection and Vaccination

Abstract

Extensive studies have demonstrated that infant immune responses are distinct from those of adults. Despite these differences, infant immunization can elicit protective immune responses at levels comparable to or, in some cases, higher than adult immune responses to many vaccines. To date, only a few HIV vaccine candidates have been tested in infant populations, and none of them evaluated vaccine efficacy. Recent exciting studies showing that HIV-infected infants can develop broad neutralizing antibody responses and that some HIV vaccine regimens can elicit high levels of potentially protective antibodies in infants provide support for the development and testing of HIV vaccines in pediatric populations. In this review, we discuss the differences in adult and infant immune responses in the setting of HIV infection and vaccination.

FIG 1

Infant HIV vaccination elicits high frequency of potentially protective anti-V1V2 IgG responses. Shown are the proportions of infants vaccinated with the Chiron vaccine (n = 43), the VaxGen vaccine (n = 44), and the ALVAC + AIDSVAX regimen (n = 7) with detectable IgG antibodies against gp70 B case A V1V2 at peak immunogenicity and subsequent time points. The reported proportion of adult RV144 vaccine recipients with a detectable IgG response against the gp70 B case A V1V2 construct (101) is presented for comparison.