Increased immunogenicity of HIV-1 p24 and gp120 following immunization with gp120/p24 fusion protein vaccine expressing alpha-gal epitopes.
Developing an effective HIV-1 vaccine will require strategies to enhance antigen presentation to the immune system. In a previous study we demonstrated a marked increase in immunogenicity of the highly glycosylated HIV-1 gp120 protein following enzymatic addition of alpha-gal epitopes to the carbohydrate chains. In the present study we determined whether gp120(alphagal) can also serve as an effective platform for targeting other HIV-1 proteins to APC and thus increase immunogenicity of both proteins. For this purpose we produced a recombinant fusion protein between gp120 and the HIV-1 matrix p24 protein (gp120/p24). Multiple alpha-gal epitopes were synthesized enzymatically on the gp120 portion of the fusion protein to generate a gp120(alphagal)/p24 vaccine. Immune responses to gp120(alphagal)/p24 compared to gp120/p24 vaccine lacking alpha-gal epitopes were evaluated in alpha1,3galactosyltransferase knockout (KO) mice. These mice lack alpha-gal epitopes and, therefore, are capable of producing the anti-Gal antibody. T cell responses to p24, as assessed by ELISPOT and by CD8+ T cells intracellular staining assays for IFNgamma, was on average 12- and 10-fold higher, respectively, in gp120(alphagal)/p24 immunized mice than in mice immunized with gp120/p24. In addition, cellular and humoral immune responses against gp120 were higher by 10-30-fold in mice immunized with gp120(alphagal)/p24 than in gp120/p24 immunized mice. Our data suggest that the alpha-gal epitopes on the gp120 portion of the fusion protein can significantly augment the immunogenicity of gp120, as well as that of the fused viral protein which lacks alpha-gal epitopes. This strategy of anti-Gal mediated targeting to APC may be used for production of effective HIV-1 vaccines comprised of various viral proteins fused to gp120.
Abdel-Motal
Ussama M
UM
Department of Surgery, University of Massachusetts Medical School, Worcester, MA 01655, USA. Ussama_abdel-motal@dfci.harvard.edu
Wang
Shixia
S
Awad
Amany
A
Lu
Shan
S
Wigglesworth
Kim
K
Galili
Uri
U
D016915:AIDS Vaccines / Q000276:immunology*; D000818:Animals; D057134:Antibodies, Neutralizing; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D005700:Galactosyltransferases; D006031:Glycosylation; D016655:HIV Core Protein p24 / Q000276:immunology*; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014312:Trisaccharides / Q000276:immunology*
D016915:AIDS Vaccines; D057134:Antibodies, Neutralizing; D016655:HIV Core Protein p24; D015699:HIV Envelope Protein gp120; D011993:Recombinant Fusion Proteins; D014312:Trisaccharides; C076569:alpha-galactosyl epitope; C514793:gp120 protein, Human immunodeficiency virus 1; C514799:p24 protein, Human Immunodeficiency Virus Type 1; D007371:Interferon-gamma; D005700:Galactosyltransferases; C487611:alpha 1,3 galactosyltransferase, mouse