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Umotoy JC, de Taeye SW. Antibody Conjugates for Targeted Therapy Against HIV-1 as an Emerging Tool for HIV-1 Cure. Front Immunol 2021; 12:708806. [PMID: 34276704 PMCID: PMC8282362 DOI: 10.3389/fimmu.2021.708806] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/18/2021] [Indexed: 01/22/2023] Open
Abstract
Although advances in antiretroviral therapy (ART) have significantly improved the life expectancy of people living with HIV-1 (PLWH) by suppressing HIV-1 replication, a cure for HIV/AIDS remains elusive. Recent findings of the emergence of drug resistance against various ART have resulted in an increased number of treatment failures, thus the development of novel strategies for HIV-1 cure is of immediate need. Antibody-based therapy is a well-established tool in the treatment of various diseases and the engineering of new antibody derivatives is expanding the realms of its application. An antibody-based carrier of anti-HIV-1 molecules, or antibody conjugates (ACs), could address the limitations of current HIV-1 ART by decreasing possible off-target effects, reduce toxicity, increasing the therapeutic index, and lowering production costs. Broadly neutralizing antibodies (bNAbs) with exceptional breadth and potency against HIV-1 are currently being explored to prevent or treat HIV-1 infection in the clinic. Moreover, bNAbs can be engineered to deliver cytotoxic or immune regulating molecules as ACs, further increasing its therapeutic potential for HIV-1 cure. ACs are currently an important component of anticancer treatment with several FDA-approved constructs, however, to date, no ACs are approved to treat viral infections. This review aims to outline the development of AC for HIV-1 cure, examine the variety of carriers and payloads used, and discuss the potential of ACs in the current HIV-1 cure landscape.
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Affiliation(s)
- Jeffrey C Umotoy
- Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Center (UMC), Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
| | - Steven W de Taeye
- Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Center (UMC), Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
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Citores L, Iglesias R, Ferreras JM. Antiviral Activity of Ribosome-Inactivating Proteins. Toxins (Basel) 2021; 13:80. [PMID: 33499086 PMCID: PMC7912582 DOI: 10.3390/toxins13020080] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/14/2021] [Accepted: 01/20/2021] [Indexed: 12/13/2022] Open
Abstract
Ribosome-inactivating proteins (RIPs) are rRNA N-glycosylases from plants (EC 3.2.2.22) that inactivate ribosomes thus inhibiting protein synthesis. The antiviral properties of RIPs have been investigated for more than four decades. However, interest in these proteins is rising due to the emergence of infectious diseases caused by new viruses and the difficulty in treating viral infections. On the other hand, there is a growing need to control crop diseases without resorting to the use of phytosanitary products which are very harmful to the environment and in this respect, RIPs have been shown as a promising tool that can be used to obtain transgenic plants resistant to viruses. The way in which RIPs exert their antiviral effect continues to be the subject of intense research and several mechanisms of action have been proposed. The purpose of this review is to examine the research studies that deal with this matter, placing special emphasis on the most recent findings.
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Affiliation(s)
| | | | - José M. Ferreras
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain; (L.C.); (R.I.)
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Spiess K, Jakobsen MH, Kledal TN, Rosenkilde MM. The future of antiviral immunotoxins. J Leukoc Biol 2016; 99:911-25. [PMID: 26729815 DOI: 10.1189/jlb.2mr1015-468r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/03/2015] [Indexed: 01/06/2023] Open
Abstract
There is a constant need for new therapeutic interventions in a wide range of infectious diseases. Over the past few years, the immunotoxins have entered the stage as promising antiviral treatments. Immunotoxins have been extensively explored in cancer treatment and have achieved FDA approval in several cases. Indeed, the design of new anticancer immunotoxins is a rapidly developing field. However, at present, several immunotoxins have been developed targeting a variety of different viruses with high specificity and efficacy. Rather than blocking a viral or cellular pathway needed for virus replication and dissemination, immunotoxins exert their effect by killing and eradicating the pool of infected cells. By targeting a virus-encoded target molecule, it is possible to obtain superior selectivity and drastically limit the side effects, which is an immunotoxin-related challenge that has hindered the success of immunotoxins in cancer treatment. Therefore, it seems beneficial to use immunotoxins for the treatment of virus infections. One recent example showed that targeting of virus-encoded 7 transmembrane (7TM) receptors by immunotoxins could be a future strategy for designing ultraspecific antiviral treatment, ensuring efficient internalization and hence efficient eradication of the pool of infected cells, both in vitro and in vivo. In this review, we provide an overview of the mechanisms of action of immunotoxins and highlight the advantages of immunotoxins as future anti-viral therapies.
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Affiliation(s)
- Katja Spiess
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Denmark; and
| | - Mette Høy Jakobsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Denmark; and
| | - Thomas N Kledal
- Section for Virology, Veterinary Institute, The Danish Technical University, Denmark
| | - Mette M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Denmark; and
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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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Gilabert-Oriol R, Weng A, Mallinckrodt BV, Melzig MF, Fuchs H, Thakur M. Immunotoxins constructed with ribosome-inactivating proteins and their enhancers: a lethal cocktail with tumor specific efficacy. Curr Pharm Des 2014; 20:6584-643. [PMID: 25341935 PMCID: PMC4296666 DOI: 10.2174/1381612820666140826153913] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 08/05/2014] [Indexed: 11/30/2022]
Abstract
The term ribosome-inactivating protein (RIP) is used to denominate proteins mostly of plant origin, which have N-glycosidase enzymatic activity leading to a complete destruction of the ribosomal function. The discovery of the RIPs was almost a century ago, but their usage has seen transition only in the last four decades. With the advent of antibody therapy, the RIPs have been a subject of extensive research especially in targeted tumor therapies, which is the primary focus of this review. In the present work we enumerate 250 RIPs, which have been identified so far. An attempt has been made to identify all the RIPs that have been used for the construction of immunotoxins, which are conjugates or fusion proteins of an antibody or ligand with a toxin. The data from 1960 onwards is reviewed in this paper and an extensive list of more than 450 immunotoxins is reported. The clinical reach of tumor-targeted toxins has been identified and detailed in the work as well. While there is a lot of potential that RIPs embrace for targeted tumor therapies, the success in preclinical and clinical evaluations has been limited mainly because of their inability to escape the endo/lysosomal degradation. Various strategies that can increase the efficacy and lower the required dose for targeted toxins have been compiled in this article. It is plausible that with the advancements in platform technologies or improved endosomal escape the usage of tumor targeted RIPs would see the daylight of clinical success.
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Affiliation(s)
| | | | | | | | | | - Mayank Thakur
- Institut fur Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Charite - Universitatsmedizin Berlin, Campus Virchow-Klinikum (Forum 4), Augustenburger Platz 1, D-13353 Berlin, Germany.
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Valentine M, Song K, Maresh GA, Mack H, Huaman MC, Polacino P, Ho O, Cristillo A, Kyung Chung H, Hu SL, Pincus SH. Expression of the memory marker CD45RO on helper T cells in macaques. PLoS One 2013; 8:e73969. [PMID: 24023920 PMCID: PMC3762710 DOI: 10.1371/journal.pone.0073969] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 07/25/2013] [Indexed: 11/18/2022] Open
Abstract
Background In humans it has been reported that a major site of the latent reservoir of HIV is within CD4+ T cells expressing the memory marker CD45RO, defined by the mAb UCHL1. There are conflicting reports regarding the expression of this antigen in macaques, the most relevant animal species for studying HIV pathogenesis and testing new therapies. There is now a major effort to eradicate HIV reservoirs and cure the infection. One approach is to eliminate subsets of cells housing the latent reservoir, using UCHL1 to target these cells. So that such studies may be performed in macaques, it is essential to determine expression of CD45RO. Methods We have used immunofluorescence and flow cytometry to study cell surface expression of CD45RO on lymphocytes from PBMC, lymphoid, and GI organs of rhesus, pigtailed, and cynomolgus macaques. Both direct and indirect immunofluorescence experiments were performed. Findings CD45RO is expressed on a subset of CD4+ lymphocytes of all pigtailed, a fraction of rhesus, and neither of the cynomolgus macaques studied. The binding of UCHL1 to macaque cells was of lower avidity than to human cells. This could be overcome by forming UCHL1 multimers. Directly conjugating fluors to UCHL1 can inhibit UCHL1 binding to macaque cells. Patterns of UCHL1 expression differ somewhat in macaques and humans, and from that of other memory markers often used in macaques. Conclusions CD45RO, defined with mAb UCHL1, is well expressed on CD4+ cells in pigtailed macaques. Using tissues recovered from latently infected pigtailed macaques we are determining whether UCHL1, or other memory markers, can define the cellular locus of the reservoir. The low avidity of this interaction could limit the utility of UCHL1, in its conventional form, to eliminate cells in vivo and test this approach in macaque models of HIV infection.
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Affiliation(s)
- Michael Valentine
- Research Institute for Children, Children’s Hospital, New Orleans, Louisiana, United States of America
- Departments of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Kejing Song
- Research Institute for Children, Children’s Hospital, New Orleans, Louisiana, United States of America
| | - Grace A. Maresh
- Research Institute for Children, Children’s Hospital, New Orleans, Louisiana, United States of America
| | - Heather Mack
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
| | - Maria Cecilia Huaman
- Advanced BioScience Laboratories Inc., Rockville, Maryland, United States of America
| | - Patricia Polacino
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
| | - On Ho
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
| | - Anthony Cristillo
- Advanced BioScience Laboratories Inc., Rockville, Maryland, United States of America
| | - Hye Kyung Chung
- Advanced BioScience Laboratories Inc., Rockville, Maryland, United States of America
| | - Shiu-Lok Hu
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
| | - Seth H. Pincus
- Research Institute for Children, Children’s Hospital, New Orleans, Louisiana, United States of America
- Departments of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pediatrics, LSU Health Sciences Center, New Orleans, Louisiana, United States of America
- * E-mail:
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7
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Abstract
PURPOSE OF REVIEW Despite the proven efficacy of highly active antiretroviral therapy in reducing mortality and morbidity of HIV infection, longer-term strategies are less well defined and there is renewed interest in HIV eradication. This review will describe the major obstacles that need to be overcome and the key new advances and strategies designed to achieve an HIV cure. RECENT FINDINGS Characterization of the HIV viral reservoir over the past few years has led to a better understanding of which approaches might successfully lead to eradication. A number of approaches such as histone modification, immunotoxins, gene therapy and gene knockout strategies have resulted and have been explored initially in vitro. There has been progression from both laboratory and animal model studies, and clinical trials are now underway using new approaches such as histone deacetylase inhibitors and zinc finger nucleases. SUMMARY Although there is currently no cure for HIV infection, there has been a resurgence of interest in the field with the development of a number of potential new approaches, some of which have entered clinical trials.
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Affiliation(s)
- John Frater
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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9
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Abstract
Highly active antiretroviral therapy (HAART) has markedly decreased morbidity and mortality in human immunodeficiency virus type 1 (HIV-1)-infected individuals in the developed world. Successful therapy often results in stable plasma levels of HIV-1 RNA below the limits of detection of commercial assays. Nonetheless, HIV-1 has not been cured by HAART. The causes of persistence of HIV infection in the face of current therapy appear to be multifactorial: latent but replication-competent provirus in resting CD4+ T cells, cryptic viral expression below the limits of detection of clinical assays, and viral sanctuary sites might all contribute to persistence. Clearance of HIV infection will almost certainly require a multimodality approach that includes potent suppression of HIV replication, therapies that reach all compartments of residual HIV replication and depletion of any reservoirs of persistent, quiescent proviral infection. This review highlights the basic mechanisms for the establishment and maintenance of viral reservoirs and pharmaceutical approaches towards their elimination.
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Abstract
The success of highly active antiretroviral therapy (HAART) for HIV-1 infection has sparked interest in mechanisms by which the virus can persist despite effectively suppressive therapy. Latent HIV-1 reservoirs established early during infection not only prevent sterilizing immunity but also represent a major obstacle to virus eradication. When HIV-1 gains a foothold in the immunologic memory or in certain inaccessible compartments of the human body, it cannot be easily purged by HAART and is able to replenish systemic infection on treatment interruption. Because latently infected cells are indistinguishable from uninfected cells, deliberate activation of latent infection combined with intensified HAART seems to be the best strategy to combat latent infection. Initial hypothesis-driven clinical trials did not achieve their ultimate goal, although they provided valuable insight for the design of future eradication protocols. A more detailed understanding of the basic mechanisms underlying the establishment and long-term maintenance of HIV-1 reservoirs will be critical in developing new eradication approaches.
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Kennedy PE, Bera TK, Wang QC, Gallo M, Wagner W, Lewis MG, Berger EA, Pastan I. Anti-HIV-1 immunotoxin 3B3(Fv)-PE38: enhanced potency against clinical isolates in human PBMCs and macrophages, and negligible hepatotoxicity in macaques. J Leukoc Biol 2006; 80:1175-82. [PMID: 16923920 DOI: 10.1189/jlb.0306139] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Highly active antiretroviral therapy (HAART) against human immunodeficiency virus type 1 (HIV-1) infection dramatically suppresses viral load, leading to marked reductions in HIV-1 associated morbidity and mortality. However, infected cell reservoirs and low-level replication persist in the face of suppressive HAART, leading invariably to viral rebound upon cessation of treatment. Toxins engineered to target the Env glycoprotein on the surface of productively infected cells represent a complementary strategy to deplete these reservoirs. We described previously highly selective killing of Env-expressing cell lines by CD4(178)-PE40 and 3B3(Fv)-PE38, recombinant derivatives of Pseudomonas aeruginosa exotoxin A containing distinct targeting moieties against gp120. In the present report, we compare the in vitro potency and breadth of these chimeric toxins against multiple clinical HIV-1 isolates, replicating in biologically relevant primary human target cell types. In PBMCs, 3B3(Fv)-PE38 blocked spreading infection by all isolates examined, with greater potency than CD4(178)-PE40. 3B3(Fv)-PE38 also potently inhibited spreading HIV-1 infection in primary macrophages. Control experiments demonstrated that in both target cell types, most of the 3B3(Fv)-PE38 activity was due to selective killing of infected cells, and not merely to neutralization by the antibody moiety of the chimeric toxin. High-dose treatment of rhesus macaques with 3B3(Fv)-PE38 did not induce liver toxicity, whereas equivalent dosage of CD4(178)-PE40 induced mild hepatotoxicity. These findings highlight the potential use of 3B3(Fv)-PE38 for depleting HIV-infected cell reservoirs persisting in the face of HAART.
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Affiliation(s)
- Paul E Kennedy
- Laboratory of Viral Diseases, NIAID, National Institutes of Health Building 4, Room 237 Bethesda, MD 20892, USA
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12
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Saavedra-Lozano J, McCoig CC, Cao Y, Vitetta ES, Ramilo O. Zidovudine, lamivudine, and abacavir have different effects on resting cells infected with human immunodeficiency virus in vitro. Antimicrob Agents Chemother 2004; 48:2825-30. [PMID: 15273087 PMCID: PMC478513 DOI: 10.1128/aac.48.8.2825-2830.2004] [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] [Indexed: 11/20/2022] Open
Abstract
We have previously described an in vitro model for the evaluation of the effects of different immunomodulatory agents and immunotoxins (ITs) on cells latently infected with human immunodeficiency virus (HIV). We demonstrated that latently infected, replication-competent cells can be generated in vitro after eliminating CD25+ cells with an IT. Thus, by selectively killing the productively infected cells with an anti-CD25 IT we can generate a population of latently infected cells. CD25- cells generated in this manner were treated with nucleoside analog reverse transcriptase inhibitors and subsequently activated with phytohemagglutinin in the presence of the drugs. The antiviral activities of zidovudine (ZDV), lamivudine (3TC), and abacavir (ABC) were evaluated by using this model. 3TC and ABC demonstrated significant activity in decreasing HIV production from recently infected resting cells following their activation, whereas the effect of ZDV was more modest. These results suggest that the differences in antiviral activity of nucleoside analogs on resting cells should be considered when designing drug combinations for the treatment of HIV infection. The model presented here offers a convenient alternative for evaluating the mechanism of action of new antiretroviral agents (J. Saavedra, C. Johnson, J. Koester, M. St. Claire, E. Vitteta, O. Ramilo, 37th Intersci. Conf. Antimicrob. Agents Chemother., abstr. I-59, 1997).
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Affiliation(s)
- Jesús Saavedra-Lozano
- Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9063, USA
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13
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Saavedra-Lozano J, Cao Y, Callison J, Sarode R, Sodora D, Edgar J, Hatfield J, Picker L, Peterson D, Ramilo O, Vitetta ES. An anti-CD45RO immunotoxin kills HIV-latently infected cells from individuals on HAART with little effect on CD8 memory. Proc Natl Acad Sci U S A 2004; 101:2494-9. [PMID: 14983037 PMCID: PMC356978 DOI: 10.1073/pnas.0308381100] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
CD4+ CD45RO+ T cells are the major latent viral reservoir in HIV-infected individuals and hence a major obstacle in curing the disease. An anti-CD45RO immunotoxin (IT) can decrease the number of both productively and latently infected CD4+ T cells obtained from HIV-infected individuals with detectable viremia. In this study, we determined whether this IT could also kill latently infected replication-competent CD4+ T cells obtained from infected individuals without detectable plasma viremia. Our results demonstrate that ex vivo treatment with the anti-CD45RO IT significantly reduced the frequency of these cells. In contrast, the IT had only a modest effect on the cytomegalovirus-specific memory responses of CD8+ T cells. These results suggest that purging latent cells from infected individuals on highly active antiretroviral therapy with the anti-CD45RO IT might reduce the HIV latent reservoir without seriously compromising CD8+ T cell memory responses.
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Affiliation(s)
- J Saavedra-Lozano
- Cancer Immunobiology Center, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Zhan J, Chen Y, Wang K, Zheng S. Expression of ricin A chain and ricin A chain-KDEL in Escherichia coli. Protein Expr Purif 2004; 34:197-201. [PMID: 15003251 DOI: 10.1016/j.pep.2003.11.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Revised: 11/10/2003] [Indexed: 10/26/2022]
Abstract
Ricin and its A chains can be used to conjugate with monoclonal antibodies to prepare immunotoxins. Ricin A chain (RTA) and its modification RTA-KDEL (ER-retrieval signal) were expressed with the pKK223.3 system in Escherichia coli under control of a tac promoter. The recombinant proteins can be purified by one-step affinity chromatography on a column of Blue-Sepharose 6B. The toxicities of RTA and its mutant RTA-KDEL were evaluated by the MTT assay in HeLa, MCF, and ECV-304 cells following fluid-phase endocytosis. RTA-KDEL was somewhat more cytotoxic than RTA itself in the different cell lines. The results suggest that rRTA-KDEL may be useful for the synthesis of more potent immunotoxins.
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Affiliation(s)
- Jinbiao Zhan
- Department of Biochemistry, Zhejiang University Medical School, 353 Yan An Road, Hangzhou 310006, PR China.
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15
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Kinter A, Moorthy A, Jackson R, Fauci AS. Productive HIV infection of resting CD4+ T cells: role of lymphoid tissue microenvironment and effect of immunomodulating agents. AIDS Res Hum Retroviruses 2003; 19:847-56. [PMID: 14585216 DOI: 10.1089/088922203322493012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ability of resting CD4+ T cells to support HIV replication is relevant to understanding how the reservoir of HIV-1-infected resting CD4+ T cells is generated, maintained and, hopefully, how it might be reduced or eliminated. We have utilized a tonsillar histoculture system to demonstrate that HIV, particularly X4 strains, can productively infect phenotypically resting CD4+ T cells in vitro and that this event is largely dependent on the lymphoid tissue microenvironment. Highly purified CD4+ tonsillar T cells that lack expression of both cell surface and nuclear antigens characteristic of classic T cell activation produce X4 HIV-1 mRNA, p24, and infectious virus while maintaining a resting phenotype when cultured in a tonsillar tissue microenvironment; in contrast, comparable purified resting CD4+ tonsillar T cells that have been exposed to X4 HIV do not support HIV replication when cultured in the absence of a lymphoid tissue microenvironment. HIV production from phenotypically resting CD4+ T cells is dramatically inhibited by anti-proinflammatory cytokine agents or immunosuppressive cytokines, but is only modestly suppressed by an inhibitor of the cell cycle. The ability of resting CD4+ T cells to support HIV replication in the microenvironment of the lymphoid tissue has implications in the pathogenesis of HIV disease and may provide an additional avenue for therapeutic intervention.
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Affiliation(s)
- Audrey Kinter
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases/NIH, MSC-1576, Building 10, Room 6A33, 10 Center Drive, Bethesda, MD 20892-1576, USA.
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16
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Abstract
Patients with chemotherapy relapsed or refractory hematologic malignancies may be effectively treated with allogeneic or autologous stem cell transplants. However, many patients cannot be transplanted due to age, comorbidities, or lack of suitable donors. Further, a fraction of patients relapse post-transplant. Novel therapeutic agents that can kill multidrug-resistant malignant stem cells and are not myelosuppressive are needed. One class of such agents is immunotoxins. Immunotoxins consist of cell-selective ligands covalently linked to peptide toxins. The ligand delivers the molecule to specific cell surface receptors on malignant cells. The toxin triggers cell death either by reaching the cytosol and catalytically inactivating vital cell processes or by modifying the tumor cell surface membrane. We have synthesized immunotoxins for therapy of chemoresistant hematologic diseases. In this review, we will detail the synthesis of a number of these drugs and describe their preclinical and clinical activity. Several of these agents have shown dramatic antitumor effects in patients with hematologic neoplasms, and one immunotoxin has been approved for use by the US Food and Drug Administration (FDA). Over the next several decades, a growing number of these agents should reach the clinic.
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Affiliation(s)
- Arthur E Frankel
- Wake Forest University School of Medicine, Winston-Salem, NC, USA
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17
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Pincus SH, Fang H, Wilkinson RA, Marcotte TK, Robinson JE, Olson WC. In vivo efficacy of anti-glycoprotein 41, but not anti-glycoprotein 120, immunotoxins in a mouse model of HIV infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:2236-41. [PMID: 12574398 DOI: 10.4049/jimmunol.170.4.2236] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunotoxins (ITs) targeting the HIV envelope protein are among the most efficacious antiviral therapies when tested in vitro. Yet a first-generation IT targeted to gp120, CD4-PE40 (chimeric immunotoxin using CD4 and the translocation and enzymatic domains of Pseudomonas exotoxin A), showed limited promise in initial clinical testing, highlighting the need for improved ITs. We have used a new mouse model of HIV infection to test the comparative efficacy of anti-HIV ITs targeted to gp120 or to gp41. Irradiated SCID/nonobese diabetic mice are injected with a tumor of human CD4(+) cells susceptible to infection and at a separate site persistently HIV-infected cells. The spread of infection from infected to susceptible tumor is monitored by plasma p24 and the presence of HIV-infected cells in the spleen. Anti-gp41 ITs in combination with tetrameric CD4-human Ig fusion protein have pronounced anti-HIV effects. Little if any anti-HIV efficacy was found with either CD4-PE40 or an Ab-targeted anti-gp120 IT. These data support continued exploration of the utility of ITs for HIV infection, particularly the use of anti-gp41 ITs in combination with soluble CD4 derivatives.
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MESH Headings
- Animals
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/pharmacokinetics
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Viral/administration & dosage
- Antibodies, Viral/therapeutic use
- CD4 Immunoadhesins/administration & dosage
- CD4 Immunoadhesins/therapeutic use
- Disease Models, Animal
- Drug Therapy, Combination
- HIV Envelope Protein gp120/immunology
- HIV Envelope Protein gp41/immunology
- HIV Infections/immunology
- HIV Infections/prevention & control
- HIV Infections/virology
- HIV-1/immunology
- HeLa Cells
- Humans
- Immunotoxins/administration & dosage
- Immunotoxins/pharmacokinetics
- Immunotoxins/therapeutic use
- Injections, Intraperitoneal
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Ricin/administration & dosage
- Ricin/pharmacokinetics
- Ricin/therapeutic use
- Tumor Cells, Cultured
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Affiliation(s)
- Seth H Pincus
- Department of Microbiology and Animal Resources Center, Montana State University, Bozeman, MT 59717, USA.
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18
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Abstract
In most infected individuals, HIV-1 replicates high levels throughout the duration of infection, including the clinically quiescent phase of disease. The level of this active viral replication correlates directly with disease progression and survival. The advent of combination therapeutics for HIV-1 (i.e., highly active antiretroviral therapy [HAART]) has led to dramatic reductions in viral replication in vivo and morbidity and mortality, at least in the developed world.
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Affiliation(s)
- Roger J Pomerantz
- Dorrance H. Hamilton Laboratory, Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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19
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Lum JJ, Pilon AA, Sanchez-Dardon J, Phenix BN, Kim JE, Mihowich J, Jamison K, Hawley-Foss N, Lynch DH, Badley AD. Induction of cell death in human immunodeficiency virus-infected macrophages and resting memory CD4 T cells by TRAIL/Apo2l. J Virol 2001; 75:11128-36. [PMID: 11602752 PMCID: PMC114692 DOI: 10.1128/jvi.75.22.11128-11136.2001] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2001] [Accepted: 08/08/2001] [Indexed: 12/31/2022] Open
Abstract
Because the persistence of human immunodeficiency virus (HIV) in cellular reservoirs presents an obstacle to viral eradication, we evaluated whether tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) induces apoptosis in such reservoirs. Lymphocytes and monocyte-derived macrophages (MDM) from uninfected donors do not die following treatment with either leucine zipper human TRAIL (LZhuTRAIL) or agonistic anti-TRAIL receptor antibodies. By contrast, such treatment induces apoptosis of in vitro HIV-infected MDM as well as peripheral blood lymphocytes from HIV-infected patients, including CD4(+) CD45RO(+) HLA-DR(-) lymphocytes. In addition, LZhuTRAIL-treated cells produce less viral RNA and p24 antigen than untreated controls. Whereas untreated cultures produce large amounts of HIV RNA and p24 antigen, of seven treated CD4(+) CD45RO(+) HLA-DR(-) cell cultures, viral RNA production was undetectable in all, p24 antigen was undetectable in six, and proviral DNA was undetectable in four. These data demonstrate that TRAIL induces death of cells from HIV-infected patients, including cell types which harbor latent HIV reservoirs.
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Affiliation(s)
- J J Lum
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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20
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Abstract
Building on the success of combination antiretroviral drug therapy will require a better understanding of the underlying basis for viral persistence. Characterization of the therapeutic, viral, and immunological factors that influence the size and stability of viral reservoirs will foster the development of strategies to control or eliminate HIV-1 from infected individuals. Here we review recent work aimed at delineating the complex interplay between viral replication, the immune system, and viral reservoirs. Finally, we address the implications and clinical significance of the residual replication that persists in infected individuals on potent antiretroviral therapy to evaluate both the possible risks and benefits of ongoing HIV-1 replication.
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Affiliation(s)
- M E Sharkey
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical Center, Worcester, Massachusetts 01605, USA
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21
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Butera ST. Therapeutic targeting of human immunodeficiency virus type-1 latency: current clinical realities and future scientific possibilities. Antiviral Res 2000; 48:143-76. [PMID: 11164503 DOI: 10.1016/s0166-3542(00)00133-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Factors affecting HIV-1 latency present formidable obstacles for therapeutic intervention. As these obstacles have become a clinical reality, even with the use of potent anti-retroviral regimens, the need for novel therapeutic strategies specifically targeting HIV-1 latency is evident. However, therapeutic targeting of HIV-1 latency requires an understanding of the mechanisms regulating viral quiescence and activation. These mechanisms have been partially delineated using chronically infected cell models and, clearly, HIV-1 activation from latency involves several key viral and cellular components. Among these distinctive therapeutic targets, cellular factors involved in HIV-1 transcription especially warrant further consideration for rational drug design. Exploring the scientific possibilities of new therapies targeting HIV-1 latency may hold new promise of eventual HIV-1 eradication.
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Affiliation(s)
- S T Butera
- HIV and Retrovirology Branch, Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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22
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Pierson T, McArthur J, Siliciano RF. Reservoirs for HIV-1: mechanisms for viral persistence in the presence of antiviral immune responses and antiretroviral therapy. Annu Rev Immunol 2000; 18:665-708. [PMID: 10837072 DOI: 10.1146/annurev.immunol.18.1.665] [Citation(s) in RCA: 382] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The success of combination antiretroviral therapy for HIV-1 infection has generated interest in mechanisms by which the virus can persist in the body despite the presence of drugs that effectively inhibit key steps in the virus life cycle. It is becoming clear that viral reservoirs established early in the infection not only prevent sterilizing immunity but also represent a major obstacle to curing the infection with the potent antiretroviral drugs currently in use. Mechanisms of viral persistence are best considered in the context of the dynamics of viral replication in vivo. Virus production in infected individuals is largely the result of a dynamic process involving continuous rounds of de novo infection of and replication in activated CD4(+) T cells with rapid turnover of both free virus and virus-producing cells. This process is largely, but not completely, interrupted by effective antiretroviral therapy. After a few months of therapy, plasma virus levels become undetectable in many patients. Analysis of viral decay rates initially suggested that eradication of the infection might be possible. However, there are several potential cellular and anatomical reservoirs for HIV-1 that may contribute to long-term persistence of HIV-1. These include infected cell in the central nervous system and the male urogenital tract. However, the most worrisome reservoir consists of latently infected resting memory CD4(+) T cells carrying integrated HIV-1 DNA. Definitive demonstration of the presence of this form of latency required development of methods for isolating extremely pure populations of resting CD4(+) T cells and for demonstrating that a small fraction of these cells contain integrated HIV-1 DNA that is competent for replication if the cells undergo antigen-driven activation. Most of the latent virus in resting CD4(+) T cells is found in cells of the memory phenotype. The half-life of this latent reservoir is extremely long (44 months). At this rate, eradication of this reservoir would require over 60 years of treatment. Thus, latently infected resting CD4(+) T cells provide a mechanism for life-long persistence of replication-competent forms of HIV-1, rendering unrealistic hopes of virus eradication with current antiretroviral regimens. The extraordinary stability of the reservoir may reflect gradual reseeding by a very low level of ongoing viral replication and/or mechanisms that contribute to the intrinsic stability of the memory T cell compartment. Given the substantial long-term toxicities of current combination therapy regimens, novel approaches to eradicating this latent reservoir are urgently needed.
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Affiliation(s)
- T Pierson
- Department of Medicine and Neurology, Johns Hopkins University School of Medicine Baltimore, Maryland 21205, USA
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23
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Gibb DM, Newberry A, Klein N, de Rossi A, Grosch-Woerner I, Babiker A. Immune repopulation after HAART in previously untreated HIV-1-infected children. Paediatric European Network for Treatment of AIDS (PENTA) Steering Committee. Lancet 2000; 355:1331-2. [PMID: 10776748 DOI: 10.1016/s0140-6736(00)02117-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In 25 vertically HIV-infected children receiving highly-active antiretroviral therapy, a 3-log10 reduction in plasma HIV RNA load was maintained for 1 year and was associated with a doubling of the CD4-cell percentage. Most (75%) new CD4 cells carried the CD45RA marker of naive cells and there was only a small rise in memory cells (CD45RO). This pattern of immune restoration differs from adults, and may be due to the presence of a functioning thymus in children.
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