Targeting antibody responses to the membrane proximal external region of the envelope glycoprotein of human immunodeficiency virus.
Although human immunodeficiency type 1 (HIV-1) infection induces strong antibody responses to the viral envelope glycoprotein (Env) only a few of these antibodies possess the capacity to neutralize a broad range of strains. The induction of such antibodies represents an important goal in the development of a preventive vaccine against the infection. Among the broadly neutralizing monoclonal antibodies discovered so far, three (2F5, Z13 and 4E10) target the short and hidden membrane proximal external region (MPER) of the gp41 transmembrane protein. Antibody responses to MPER are rarely observed in HIV-infected individuals or after immunization with Env immunogens. To initiate antibody responses to MPER in its membrane-embedded native conformation, we generated expression plasmids encoding the membrane-anchored ectodomain of gp41 with N-terminal deletions of various sizes. Following transfection of these plasmids, the MPER domains are displayed on the cell surface and incorporated into HIV virus like particles (VLP). Transfected cells displaying MPER mutants bound as efficiently to both 2F5 and 4E10 as cells transfected with a plasmid encoding full-length Env. Mice immunized with VLPs containing the MPER mutants produced MPER-specific antibodies, the levels of which could be increased by the trimerization of the displayed proteins as well as by a DNA prime-VLP boost immunization strategy. Although 2F5 competed for binding to MPER with antibodies in sera of some of the immunized mice, neutralizing activity could not be detected. Whether this is due to inefficient binding of the induced antibodies to MPER in the context of wild type Env or whether the overall MPER-specific antibody response induced by the MPER display mutants is too low to reveal neutralizing activity, remains to be determined.
Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany.
Donatien
D
Kamdem Toukam
Matthias
M
Tenbusch
Alexander
A
Stang
Vladimir
V
Temchura
Michael
M
Storcksdieck Genannt Bonsmann
Bastian
B
Grewe
Stefanie
S
Koch
Andreas
A
Meyerhans
Godwin
G
Nchinda
Lazare
L
Kaptue
Klaus
K
Uberla
D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis* / Q000276:immunology; D000917:Antibody Formation / Q000235:genetics*; D002462:Cell Membrane / Q000821:virology*; D004279:DNA, Viral / Q000276:immunology; D005260:Female; D057809:HEK293 Cells; D015700:HIV Envelope Protein gp41 / Q000737:chemistry* / Q000235:genetics*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015202:Protein Engineering / Q000379:methods*; D058425:Vaccines, Virus-Like Particle / Q000276:immunology
D000914:Antibodies, Viral; D004279:DNA, Viral; D015700:HIV Envelope Protein gp41; D010446:Peptide Fragments; D058425:Vaccines, Virus-Like Particle; C514787:gp41 protein, Human immunodeficiency virus 1