Development and Preclinical Evaluation of an Integrase Defective Lentiviral Vector Vaccine Expressing the HIVACAT T Cell Immunogen in Mice

Abstract

Cellular immune responses play a fundamental role in controlling viral replication and AIDS progression in human immunodeficiency virus (HIV)-infected subjects and in simian immunodeficiency virus (SIV)-infected macaques. Integrase defective lentiviral vector (IDLV) represents a promising vaccine candidate, inducing functional and durable immune responses in mice and non-human primates. Here, we designed HIV-and SIV-based IDLVs to express the HIVACAT T cell immunogen (HTI), a mosaic antigen designed to cover vulnerable sites in HIV-1 Gag, Pol, Vif, and Nef. We observed that HTI expression during lentiviral vector production interfered profoundly with IDLV particles release because of sequestration of both HIV-and SIV-Gag proteins in the cytoplasm of the vector-producing cells. However, modifications in IDLV design and vector production procedures greatly improved recovery of both HIV-and SIV-based IDLV-HTI. Immunization experiments in BALB/c mice showed that both IDLVs elicited HTI-specific T cell responses. However, immunization with HIV-based IDLV elicited also a T cell response toward exogenous HIV proteins in IDLV particles, suggesting that SIV-based IDLV may be a preferable platform to assess the induction of transgene-specific immune responses against rationally designed HIV structural antigens. These data support the further evaluation of IDLV as an effective platform of T cell immunogens for the development of an effective HIV vaccine.

An Update on the HIV DNA Vaccine Strategy

“…Besides, there was no evidence of vector mobilization or recombination in the immunized and subsequently challenged monkeys suggesting the potential use of IDLVs for prophylactic HIV vaccines. Similar results were also reported by Gallinaro et al [100].…”

Priming with Recombinant BCG Expressing HTI Enhances the Magnitude and Breadth of the T-Cell Immune Responses Elicited by MVA.HTI in BALB/c Mice

“…When assessing the individual peptide pool responses, the most reactive were peptides 1G p24, 1K prot, 2B RT and 2C int, consistent with observations from previous data where BCG.HTI 2auxo.int was combined with ChAdOx1.HTI [ 31 ]. These data were compared with other vaccine vectors expressing HTI, such as DNA.HTI developed by Mothe et al [ 30 ], and the integrase defective lentiviral vector vaccine expressing HTI, developed by Gallinaro et al [ 38 ]. In Gallinaro’s paper, they stated that pools 6 and 7, covering HIV protease and reverse transcriptase respectively, were the most reactive in mice experiments.…”

Persistent Immunogenicity of Integrase Defective Lentiviral Vectors delivering membrane tethered Native-Like HIV-1 Envelope Trimers

“…The copyright holder for this preprint this version posted October 9, 2021. ; https://doi.org/10.1101/2021.10.08.462761 doi: bioRxiv preprint IDLVs were obtained by including pSIV-GagGFP plasmid 34 , in which the carboxy-terminus of SIV-Gag protein is fused to the GFP allowing for the incorporation of Gag-GFP fusion protein into IDLV-UFO.750 particles. IDLV-UFO.750 particles were stained with 2G12 or PGT145 and we observed co-localization of ConSOSL.UFO.750 and SIV-GagGFP (Fig.…”

“…SIV-based self-inactivating (SIN) transfer vector expressing GFP (pGAE-CMV-GFP-W, hereafter referred to as pGAE-GFP), Integrase-competent and Integrase-defective packaging vectors (pAdSIV3+ and pAdSIVD4V, respectively) and plasmids expressing vesicular stomatitis virus envelope glycoprotein G (VSV.G) from Indiana or Cocal serotype (phCMV-VSV.G and pMD2-Cocal.G, respectively) have been already described 44,58,59 . expressing ConSgp160 Env and pCDNA3-SIVGag-GFP expressing the codon optimized sequence of SIVGag fused to the GFP sequence, have been previously described 11,34 . Schematic representation of plasmids described above is shown in Supplementary Fig.…”