Characterization of Humoral and Cellular Immune Responses Elicited by a Recombinant Adenovirus Serotype 26 HIV-1 Env Vaccine in Healthy Adults (IPCAVD 001).

Publication Type:

Journal Article


The Journal of infectious diseases, Volume 207, Issue 2, p.248-56 (2013)


2013, Center-Authored Paper, Clinical Research Division, November 2012, Vaccine and Infectious Disease Division


Background. Adenovirus serotype 26 (Ad26) has been developed as a novel candidate vaccine vector for HIV-1 and other pathogens. The primary safety and immunogenicity data from IPCAVD 001, the first-in-human evaluation of a prototype Ad26 vector-based vaccine expressing clade A HIV-1 Env (Ad26.ENVA.01), is reported concurrently with this manuscript. Here we characterize in greater detail the humoral and cellular immune responses elicited by Ad26.ENVA.01 in humans.Methods. Samples from IPCAVD 001 were utilized for humoral and cellular immunogenicity assays.Results. We observed a dose-dependent expansion of the magnitude, breadth, and epitopic diversity of Env-specific binding antibody responses elicited by this vaccine. Antibody-dependent cell-mediated phagocytosis, virus inhibition, and degranulation functional activity was also observed. Env-specific cellular immune responses induced by the vaccine included multiple CD8+ and CD4+ T lymphocyte memory subpopulations and cytokine secretion phenotypes, although cellular immune breadth was limited. Baseline vector-specific T lymphocyte responses were common but did not impair Env-specific immune responses in this study.Conclusion. Ad26.ENVA.01 elicited a broad diversity of humoral and cellular immune responses in humans. These data support the further clinical development of Ad26 as a candidate vaccine vector.