title: A chimeric HIV-1 envelope glycoprotein trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF) domain induces enhanced antibody and T cell responses.
abstract: An effective HIV-1 vaccine should ideally induce strong humoral and cellular immune responses that provide sterilizing immunity over a prolonged period. Current HIV-1 vaccines have failed in inducing such immunity. The viral envelope glycoprotein complex (Env) can be targeted by neutralizing antibodies to block infection, but several Env properties limit the ability to induce an antibody response of sufficient quantity and quality. We hypothesized that Env immunogenicity could be improved by embedding an immunostimulatory protein domain within its sequence. A stabilized Env trimer was therefore engineered with the granulocyte-macrophage colony-stimulating factor (GM-CSF) inserted into the V1V2 domain of gp120. Probing with neutralizing antibodies showed that both the Env and GM-CSF components of the chimeric protein were folded correctly. Furthermore, the embedded GM-CSF domain was functional as a cytokine in vitro. Mouse immunization studies demonstrated that chimeric Env(GM-CSF) enhanced Env-specific antibody and T cell responses compared with wild-type Env. Collectively, these results show that targeting and activation of immune cells using engineered cytokine domains within the protein can improve the immunogenicity of Env subunit vaccines.
authors.affiliation: Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Thijs
authors.initials: T
authors.lastname: van Montfort
authors.forename: Mark
authors.initials: M
authors.lastname: Melchers
authors.forename: Gözde
authors.initials: G
authors.lastname: Isik
authors.forename: Sergey
authors.initials: S
authors.lastname: Menis
authors.forename: Po-Ssu
authors.initials: PS
authors.lastname: Huang
authors.forename: Katie
authors.initials: K
authors.lastname: Matthews
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Michael
authors.forename: Ben
authors.initials: B
authors.lastname: Berkhout
authors.forename: William R
authors.initials: WR
authors.lastname: Schief
authors.forename: John P
authors.initials: JP
authors.lastname: Moore
authors.forename: Rogier W
authors.initials: RW
authors.lastname: Sanders
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000918:Antibody Specificity; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics* / Q000276:immunology*; D057809:HEK293 Cells; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015202:Protein Engineering; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014765:Viral Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D015699:HIV Envelope Protein gp120; D011993:Recombinant Fusion Proteins; D014765:Viral Vaccines; C514793:gp120 protein, Human immunodeficiency virus 1; D016178:Granulocyte-Macrophage Colony-Stimulating Factor