Enhancement of cellular and humoral immune responses to human immunodeficiency virus type 1 Gag and Pol by a G/P-92 fusion protein expressing highly immunogenic Gag p17/p24 and Pol p51 antigens.
OBJECTIVE
Immunity to the human immunodeficiency virus type-1 (HIV-1) G/P-92 fusion protein consisting of highly immunogenic regions of Gag (p17 and p24) and Pol (p51) expressed in recombinant vaccinia virus (vG/P-92) was compared with responses to the entire viral Gag-Pol precursor protein (vVK1).


METHODS
We analyzed the level of Gag and Pol protein expression in vG/P-92-infected cells as well as the ability of the G/P-92 fusion protein to form virus-like particles (VLP) in infected cultures. The efficacy of vG/P-92 and vVK1 vaccines was evaluated in a murine model by measuring T helper (Th), cytotoxic T lymphocyte (CTL), and antibody responses to Gag and Pol antigens.


RESULTS
The deletion of a frameshift site resulted in an increased level of Pol in cells expressing the G/P-92 fusion protein. Particles budding from the plasma membrane were detected in both vG/P-92- and vVK1-infected cells, but the release of VLP was less efficient from cells expressing the G/P-92 fusion protein than the entire gag-pol gene product. Immunization with vG/P-92 vector elicited a higher level of cellular and humoral responses to both Gag and Pol antigens than the vVK1 vaccine.


CONCLUSIONS
The enhanced immunogenicity of the G/P-92 fusion protein compared with the entire viral gag-pol gene product might be related to a higher intracellular level of Pol and Gag expression due to the deletion of a frameshift site and less efficient transport of VLP from vG/P-92-infected cells, respectively.
Kmieciak
D
D
Center for Neurovirology and Cancer Biology, Temple University, Philadelphia, Pennsylvania, USA.
Bolesta
E
E
Naito
T
T
Gzyl
J
J
Kaneko
Y
Y
Kozbor
D
D
D016915:AIDS Vaccines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D015870:Gene Expression; D015683:Gene Products, gag / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D005822:Genetic Vectors; D006183:H-2 Antigens / Q000235:genetics; D015483:HIV Antibodies / Q000097:blood / Q000276:immunology; D015488:HIV Antigens / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016655:HIV Core Protein p24 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D054303:HIV Reverse Transcriptase / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D015789:HLA-A2 Antigen / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D019169:Jurkat Cells; D051379:Mice; D008822:Mice, Transgenic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D014616:Vaccinia virus; D014764:Viral Proteins; D014771:Virion; D054301:gag Gene Products, Human Immunodeficiency Virus
D016915:AIDS Vaccines; D015683:Gene Products, gag; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D015483:HIV Antibodies; D015488:HIV Antigens; D016655:HIV Core Protein p24; D015789:HLA-A2 Antigen; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054858:p17 protein, Human Immunodeficiency Virus Type 1; D054303:HIV Reverse Transcriptase