1. Modifications of HIV-1 retrovirus-like particles to enhance safety and immunogenicity
- Author
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Fei Long Yao, Benjamin Rovinski, Michel H. Klein, George A. Cates, Shi Xian Cao, and Roy Persson
- Subjects
Molecular Sequence Data ,Gene Expression ,Gene Products, gag ,Bioengineering ,HIV Envelope Protein gp120 ,Applied Microbiology and Biotechnology ,Virus ,Retrovirus ,Gene expression ,Chlorocebus aethiops ,Animals ,Humans ,Amino Acid Sequence ,Vero Cells ,Pharmacology ,AIDS Vaccines ,Vaccines, Synthetic ,Expression vector ,General Immunology and Microbiology ,biology ,Immunogenicity ,Virus Assembly ,Virion ,RNA ,General Medicine ,biology.organism_classification ,Virology ,Macaca mulatta ,Reverse transcriptase ,HIV Reverse Transcriptase ,Peptide Fragments ,Integrase ,Consumer Product Safety ,biology.protein ,HIV-1 ,Biotechnology - Abstract
HIV-1 retrovirus-like particles can be produced in VERO cells that have been transfected with an expression construct encoding HIV-1 structural proteins. The particles are entirely non-infectious although structurally they resemble infectious virus particles. This makes them a promising candidate for use as an HIV-1 vaccine. In order to ensure their safety and enhance their immunogenicity, the retrovirus-like particles were modified in a number of ways. A large deletion in the HIV-1 pol gene has eliminated reverse transcriptase and integrase activities. Deletion of RNA packaging signals in the RNA untranslated leader sequence and in Gag reduced packaged RNA to 5% of that in HIV-1 virus. Replacement of the existing HIV-1LAI envelope protein with that of HIV-1MN has ensured that immune responses to the particles are relevant to those against the majority of HIV-1 clade B isolates. In addition to these changes in particle composition, yields of the modified particles were increased using a superior method of inducing the expression construct promoter, and an effective scheme for particle purification was developed. Immunization of non-human primates demonstrated that the particles were capable of generating anti-HIV-1 neutralizing antibodies. The technological refinements reported here will permit retrovirus-like particles to be tested safely in humans, and the change in envelope proteins should allow a more realistic evaluation of the immunogenicity of these particles. Experience gained in engineering these refinements will greatly facilitate other modifications that may be required to achieve maximum efficacy as a vaccine against HIV-1.
- Published
- 1999