Inhibition of Human Immunodeficiency Virus Type 1 Entry in Cells Expressing gp41-Derived Peptides

Abstract

As the limitations of antiretroviral drug therapy, such as toxicity and resistance, become evident, interest in alternative therapeutic approaches for human immunodeficiency virus (HIV) infection is growing. We developed the first gene therapeutic strategy targeting entry of a broad range of HIV type 1 (HIV-1) variants. Infection was inhibited at the level of membrane fusion by retroviral expression of a membrane-anchored peptide derived from the second heptad repeat of the HIV-1 gp41 transmembrane glycoprotein. To achieve maximal expression and antiviral activity, the peptide itself, the scaffold for presentation of the peptide on the cell surface, and the retroviral vector backbone were optimized. This optimized construct effectively inhibited virus replication in cell lines and primary blood lymphocytes. The membrane-anchored C-peptide was also shown to bind to free gp41 N peptides, suggesting that membrane-anchored antiviral C peptides have a mode of action similar to that of free gp41 C peptides. Preclinical toxicity and efficacy studies of this antiviral vector have been completed, and clinical trials are in preparation.

Gene therapy progress and prospects: Novel gene therapy approaches for AIDS

“…The membrane-anchored C-peptide binds to the free version of gp41 N peptides, suggesting that the membraneanchored C peptides exert their biological effect by binding gp41. 54 Although the appearance of resistant variants might be inevitable, 55 entry inhibitors as those that interfere with fusion carry great hope for anti-HIV therapy.…”

Efficient entry inhibition of human and nonhuman primate immunodeficiency virus by cell surface-expressed gp41-derived peptides

“…9 Briefly, all retroviral vectors had flanking long terminal repeats, an MP71 leader sequence 16 and an anti-HIV protein module with a signal peptide (SP), the C46 peptide fused to the hinge and linker domain and the membrane-spanning domain. We generated a set of maC46 low-and high-expressing vectors to determine whether inhibition of virus entry by membrane-anchored C46 (maC46) is dose dependent.…”

“…9 Here we expanded the repertoire of HIV-based C46 vectors (M87o HIV ) to vectors that express the C46 sequences adapted from SIVmac239 (M87o SIV ) and SHIV89.6P (M87o SHIV ), viruses that are commonly used in rhesus monkey experiments.…”

“…Also, in previous experiments we did not observe a different inhibitory capacity of RRE expressing and nonexpressing vectors. 9 Given that the efficiency of virus entry inhibition is dependent on the level of maC46 cell surface expression (FG Hermann et al, unpublished observations), we next sought to determine whether low-level cell surface expression of maC46 could still cross-protect against infection with a heterologous virus. In contrast to maC46 high-expressing vectors (M87o SIV , M87o SHIV and M87o HIV ), cell surface expression of maC46 on PM-1 cells transduced with M87o SIV low, M87o SHIV low and M87o HIV low was significantly reduced (Figure 3a).…”

“…In addition antiretroviral activity against a broad range of viral isolates was enhanced. 9 The improved M87o construct also minimized the emergence of HIV T20 escape mutants and inhibited their entry into human primary CD4+ T cells (Egelhofer et al 9 ; Lohrengel et al 10 and unpublished data). In a proof-of-concept study, M87o-transduced autologous CD8-depleted T lymphocytes were transfused into HIV-infected patients and could be detected in blood throughout the 1-year followup.…”