ABSTRACT
Following infection by HIV or SIV, reverse transcriptase (RT) directs the conversion of the single-stranded RNA genome into a double-stranded DNA molecule that integrates into the host cell genome. RT encodes for several immunogenic epitopes that are desirable for inclusion in a human vaccine for HIV infection, however, issues of safety have dampened enthusiasm for inclusion of an enzymatically-active RT molecule into an AIDS vaccine. In this study, virally-regulated, replication-incompetent lentiviral particles were expressed from DNA plasmids. The sequences for integrase, Vpr, Vif, Nef, and the long terminal repeats (LTRs) were deleted and mutations were engineered into capsid to decreases RNA packaging. Virus-like particles incorporated no RT (HIV-VLP DeltaRT or SHIV-VLP DeltaRT) or contained a full-length enzymatically-inactivated RT molecule (HIV-VLP or SHIV-VLP). Each secreted VLP was enveloped with a lipid bilayer derived from primate cells with embedded, native viral envelopes in similar concentrations as infectious virions. BALB/c mice were vaccinated (weeks 0, 3, and 6) with purified VLPs via intranasal inoculation in the presence of cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODNs). All VLPs, with or without RT, elicited both robust humoral and cellular immune responses to Gag, Pol, and Env antigens. Therefore, the lack of RT enhances the safety of these VLPs for use in future human clinical trials without a significant reduction in the overall immunogenicity of these VLP immunogens.
Subject(s)
AIDS Vaccines/immunology , Gene Deletion , HIV Infections/immunology , Lentivirus/enzymology , Lentivirus/immunology , RNA-Directed DNA Polymerase/genetics , Simian Acquired Immunodeficiency Syndrome/immunology , Virion/immunology , AIDS Vaccines/administration & dosage , Animals , Antibodies, Viral/blood , COS Cells , Chlorocebus aethiops , HIV Antigens/immunology , HIV Infections/prevention & control , HIV Infections/virology , HIV-1/enzymology , HIV-1/genetics , HIV-1/immunology , HIV-1/metabolism , Humans , Immunity, Cellular , Lentivirus/genetics , Mice , Mice, Inbred BALB C , Simian Acquired Immunodeficiency Syndrome/prevention & control , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/enzymology , Simian Immunodeficiency Virus/genetics , Simian Immunodeficiency Virus/immunology , Simian Immunodeficiency Virus/metabolism , Vaccination , Virion/enzymology , Virion/geneticsABSTRACT
The study was done to assess the performance of a system that measures the partial pressures of oxygen (pO2) from the lifetimes of oxygen-quenched luminescence of ruthenium compounds immobilized at the tip of fiber-optic optodes (Oxylite system). The system was used to measure the pO2 in brain tissue (thalamus and hypothalamus) and in the sagittal sinus of isoflurane-anesthetized rats at different FiO2's. The pO2 recorded in the hypothalamus (HPtO2) was consistently higher than the pO2 in the thalamus (TPtO2) at all FiO2. HPtO2 was closely related to PvO2 during normoxia but not during hypoxia. The equilibrium time of Oxylite system was found to be rapid compared to in vivo tissue response to changes in FiO2.
