Adjuvanted HIV-1 vaccine promotes antibody-dependent phagocytic responses and protects against heterologous SHIV challenge

PLoS Pathog. 2020 Sep 3;16(9):e1008764. doi: 10.1371/journal.ppat.1008764. eCollection 2020 Sep.


To augment HIV-1 pox-protein vaccine immunogenicity using a next generation adjuvant, a prime-boost strategy of recombinant modified vaccinia virus Ankara and multimeric Env gp145 was evaluated in macaques with either aluminum (alum) or a novel liposomal monophosphoryl lipid A (MPLA) formulation adsorbed to alum, ALFA. Binding antibody responses were robust and comparable between arms, while antibody-dependent neutrophil and monocyte phagocytotic responses were greatly enhanced by ALFA. Per-exposure vaccine efficacy against heterologous tier 2 SHIV mucosal challenge was 90% in ALFA-adjuvanted males (P = 0.002), while alum conferred no protection. Half of the ALFA-adjuvanted males remained uninfected after the full challenge series, which spanned seven months after the last vaccination. Antibody-dependent monocyte and neutrophil phagocytic responses both strongly correlated with protection. Significant sex differences in infection risk were observed, with much lower infection rates in females than males. In humans, MPLA-liposome-alum adjuvanted gp120 also increased HIV-1-specific phagocytic responses relative to alum. Thus, next-generation liposome-based adjuvants can drive vaccine elicited antibody effector activity towards potent phagocytic responses in both macaques and humans and these responses correlate with protection. Future protein vaccination strategies aiming to improve functional humoral responses may benefit from such adjuvants.

Publication types

  • Clinical Trial, Phase I
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adjuvants, Immunologic / administration & dosage*
  • Adolescent
  • Adult
  • Animals
  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / immunology*
  • Antibody Formation / immunology*
  • Double-Blind Method
  • Female
  • HIV Antibodies / immunology*
  • HIV Infections / immunology
  • HIV Infections / prevention & control*
  • HIV Infections / virology
  • HIV-1 / drug effects
  • HIV-1 / immunology
  • Humans
  • Macaca mulatta
  • Male
  • Middle Aged
  • SAIDS Vaccines / immunology
  • SAIDS Vaccines / therapeutic use*
  • Simian Acquired Immunodeficiency Syndrome / immunology
  • Simian Acquired Immunodeficiency Syndrome / prevention & control*
  • Simian Acquired Immunodeficiency Syndrome / virology
  • Simian Immunodeficiency Virus / drug effects
  • Simian Immunodeficiency Virus / immunology
  • Young Adult


  • Adjuvants, Immunologic
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • HIV Antibodies
  • SAIDS Vaccines