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Klug G, Cole FM, Hicar MD, Watt C, Peters T, Pincus SH. Identification of Anti-gp41 Monoclonal Antibodies That Effectively Target Cytotoxic Immunoconjugates to Cells Infected with Human Immunodeficiency Virus, Type 1. Vaccines (Basel) 2023; 11:vaccines11040829. [PMID: 37112741 PMCID: PMC10144985 DOI: 10.3390/vaccines11040829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
We are developing cytotoxic immunoconjugates (CICs) targeting the envelope protein (Env) of the Human Immunodeficiency Virus, type 1 (HIV) to purge the persistent reservoirs of viral infection. We have previously studied the ability of multiple monoclonal antibodies (mAbs) to deliver CICs to an HIV-infected cell. We have found that CICs targeted to the membrane-spanning gp41 domain of Env are most efficacious, in part because their killing is enhanced in the presence of soluble CD4. The ability of a mAb to deliver a CIC does not correlate with its ability to neutralize nor mediate Ab-dependent cellular cytotoxicity. In the current study, we seek to define the most effective anti-gp41 mAbs for delivering CICs to HIV-infected cells. To do this, we have evaluated a panel of human anti-gp41 mAbs for their ability to bind and kill two different Env-expressing cell lines: persistently infected H9/NL4-3 and constitutively transfected HEK293/92UG. We measured the binding and cytotoxicity of each mAb in the presence and absence of soluble CD4. We found that mAbs to the immunodominant helix-loop-helix region (ID-loop) of gp41 are most effective, whereas neutralizing mAbs to the fusion peptide, gp120/gp41 interface, and the membrane proximal external region (MPER) are relatively ineffective at delivering CICs. There was only a weak correlation between antigen exposure and killing activity. The results show that the ability to deliver an effective IC and neutralization are distinct functions of mAbs.
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Affiliation(s)
- Grant Klug
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Frances M Cole
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Mark D Hicar
- Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, The University at Buffalo, Buffalo, NY 14203, USA
| | - Connie Watt
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Tami Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Seth H Pincus
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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Denton PW, Long JM, Wietgrefe SW, Sykes C, Spagnuolo RA, Snyder OD, Perkey K, Archin NM, Choudhary SK, Yang K, Hudgens MG, Pastan I, Haase AT, Kashuba AD, Berger EA, Margolis DM, Garcia JV. Targeted cytotoxic therapy kills persisting HIV infected cells during ART. PLoS Pathog 2014; 10:e1003872. [PMID: 24415939 PMCID: PMC3887103 DOI: 10.1371/journal.ppat.1003872] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/22/2013] [Indexed: 11/18/2022] Open
Abstract
Antiretroviral therapy (ART) can reduce HIV levels in plasma to undetectable levels, but rather little is known about the effects of ART outside of the peripheral blood regarding persistent virus production in tissue reservoirs. Understanding the dynamics of ART-induced reductions in viral RNA (vRNA) levels throughout the body is important for the development of strategies to eradicate infectious HIV from patients. Essential to a successful eradication therapy is a component capable of killing persisting HIV infected cells during ART. Therefore, we determined the in vivo efficacy of a targeted cytotoxic therapy to kill infected cells that persist despite long-term ART. For this purpose, we first characterized the impact of ART on HIV RNA levels in multiple organs of bone marrow-liver-thymus (BLT) humanized mice and found that antiretroviral drug penetration and activity was sufficient to reduce, but not eliminate, HIV production in each tissue tested. For targeted cytotoxic killing of these persistent vRNA(+) cells, we treated BLT mice undergoing ART with an HIV-specific immunotoxin. We found that compared to ART alone, this agent profoundly depleted productively infected cells systemically. These results offer proof-of-concept that targeted cytotoxic therapies can be effective components of HIV eradication strategies.
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Affiliation(s)
- Paul W. Denton
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Julie M. Long
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Stephen W. Wietgrefe
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Craig Sykes
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Rae Ann Spagnuolo
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Olivia D. Snyder
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Katherine Perkey
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Nancie M. Archin
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Shailesh K. Choudhary
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Kuo Yang
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Michael G. Hudgens
- Department of Biostatistics, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Ira Pastan
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ashley T. Haase
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Angela D. Kashuba
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Edward A. Berger
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David M. Margolis
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - J. Victor Garcia
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Takebe Y, Telesnitsky A. Evidence for the acquisition of multi-drug resistance in an HIV-1 clinical isolate via human sequence transduction. Virology 2006; 351:1-6. [PMID: 16777167 PMCID: PMC2213631 DOI: 10.1016/j.virol.2006.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 05/03/2006] [Accepted: 05/09/2006] [Indexed: 12/31/2022]
Abstract
Insertions in HIV-1 reverse transcriptase's fingers subdomain can enhance chain terminator excision and confer resistance to multiple nucleoside analogs. Inserts that resemble flanking sequences likely arise by local sequence duplication. However, a remarkable variety of non-repeat fingers insertions have been observed. Here, molecular epidemiology, sequence analyses and mechanistic modeling were employed to show that one Japanese isolate's RT fingers insert likely resulted from non-homologous recombination between virus and host sequences and the transductive copying of 37 nucleotides from human chromosome 17. These findings provide evidence that human sequence transduction can, at least rarely, contribute to genetic and phenotypic variation in pandemic HIV.
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Affiliation(s)
- Yutaka Takebe
- Laboratory of Molecular Virology and Epidemiology, AIDS Research Center, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Alice Telesnitsky
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
- * Corresponding author. Fax: +1 734 764 3562. E-mail addresses: (Y. Takebe), (A. Telesnitsky)
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Van Oijen MG, Preijers FW. Rationale for the use of immunotoxins in the treatment of HIV-infected humans. J Drug Target 1998; 5:75-91. [PMID: 9588864 DOI: 10.3109/10611869808995861] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The first step in the replication of human immunodeficiency virus (HIV) is selective binding of the envelope glycoprotein (gp120) to CD4 receptors on T cells or macrophages. After penetration in these cells, the genome of the virus is integrated in the human genome. HIV-infection causes depletion of CD4-positive cells resulting in a severe immunosuppression. It is believed that eliminating HIV-infected cells is crucial in limiting further reduction of CD4-positive cells and thus, preventing disease progression. The most commonly used drugs, such as zidovudine (AZT), appeared to be not completely effective. Therefore many investigators are searching for alternative treatment modalities. The use of immunotoxins (ITs) to eliminate HIV-infected cells is discussed. ITs are chimeric molecules in which cell-binding ligands are coupled to toxins and can specifically eliminate undesired cells. The cell-binding carriers of anti-HIV ITs have been directed against different regions of the HIV envelope glycoprotein (gp120 and gp41) and surface antigens (e.g CD4, CD25). The ITs have been composed of different ribosome-inactivating proteins (RIPs) like pokeweed antiviral protein (PAP), Pseudomonas exotoxin (PE), Diphtheria toxin (DT), or ricin. In in vitro studies, several of these ITs have been shown to be effective and specific in killing acute and persistently HIV-infected cells. The ITs were effective at concentrations (ID50 range from 10(-9) M to 10(-12) M) that were not toxic to uninfected cells or cells without the antigen. The IT CD4(178)PE40, a fusion protein directed against the CD4 binding site of gp120, has been investigated in two in vivo trials. The results were disappointing considering the antiviral activity in vitro. This was thought to be due to the rapid clearance of the IT and the differential resistance of clinical HIV isolates. Use of a panel of ITs is likely to be more effective because multiple approaches cover the intrinsic variability of HIV and the presence of IT-resistant or latently infected cells, as well as the blocking presence of neutralizing anti-HIV antibodies and the immunogenicity of most ITs. It may be possible to control the virus completely with a panel of ITs in combination with other antiviral or immunosuppressive agents such as RT inhibitors (e.g AZT), interferon alpha, or cyclosporine. More research will be necessary to develop such a combined therapy.
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Affiliation(s)
- M G Van Oijen
- Department of Hematology, University Hospital St. Radboud, Nijmegen, The Netherlands
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Abstract
In vitro analyses have shown anti-HIV immunotoxins to be among the most effective AIDS antivirals tested. Because HIV has been continually selected by antibody, immunotoxins targeted to constant domains of viral antigens may not elicit drug-resistant mutants. A clinical trial with CD4-PE40, a possibly flawed immunotoxin with nonspecific toxicity and short serum half-life, has reduced interest in this form of therapy. It is proposed that the use of an immunotoxin directed against gp41 in combination with a CD4-Ig chimera is more likely to have a therapeutic effect than CD4-PE40. Clinical trials are also underway utilizing an immunotoxin that eliminates activated T-cells, an important cellular locus of HIV-replication.
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Affiliation(s)
- S H Pincus
- Department of Microbiology, Montana State University, Bozeman 59717-3520, USA.
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Duensing TD, Fang H, Dorward DW, Pincus SH. Processing of the envelope glycoprotein gp160 in immunotoxin-resistant cell lines chronically infected with human immunodeficiency virus type 1. J Virol 1995; 69:7122-31. [PMID: 7474132 PMCID: PMC189632 DOI: 10.1128/jvi.69.11.7122-7131.1995] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We describe the isolation and characterization of variant cell lines which are chronically infected with the human immunodeficiency virus (HIV) and resistant to the action of immunotoxins directed against the HIV envelope protein. These variants all produce normal levels of HIV proteins, budding virions, and the envelope protein precursor gp160. Two of the variants, 10E and 11E, contain a mutation within the env gene which results in the production of a truncated precursor and altered processing and transport of the protein to the cell surface. Variants B9 and G4 are defective in gp160 cleavage and do not efficiently transport the envelope protein to the cell surface. There are no mutations in the expressed viruses of B9 and G4. These cell lines express higher levels of CD4 protein and mRNA than H9/NL4-3. Thus, 10E, 11E, B9, and G4 have escaped immunotoxin action by downmodulating the envelope protein from their cell surfaces. None of these variants produce infectious HIV. Two other immunotoxin-resistant variants, E9-3 and 41-17, produce normal levels of gp160, efficiently transport the cleaved and processed subunits to the cell surface, and secrete infectious HIV. These studies identify alterations in gp160 processing that underscore the importance of the relationship between HIV and the cell that it infects.
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Affiliation(s)
- T D Duensing
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA
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