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S2 from equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3. Proc Natl Acad Sci U S A 2016; 113:13197-13202. [PMID: 27803322 DOI: 10.1073/pnas.1612044113] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The lentivirus equine infectious anemia virus (EIAV) encodes the small protein S2, a pathogenic determinant that is important for virus replication and disease progression in horses. No molecular function had been linked to this accessory protein. We report that S2 can replace the activity of Negative factor (Nef) in HIV-1 infectivity, being required to antagonize the inhibitory activity of Serine incorporator (SERINC) proteins on Nef-defective HIV-1. Like Nef, S2 excludes SERINC5 from virus particles and requires an ExxxLL motif predicted to recruit the clathrin adaptor, Adaptor protein 2 (AP2). Accordingly, functional endocytic machinery is essential for S2-mediated infectivity enhancement, and S2-mediated enhancement is impaired by inhibitors of clathrin-mediated endocytosis. In addition to retargeting SERINC5 to a late endosomal compartment, S2 promotes host factor degradation. Emphasizing the similarity with Nef, we show that S2 is myristoylated, and, as is compatible with a crucial role in posttranslational modification, its N-terminal glycine is required for anti-SERINC5 activity. EIAV-derived vectors devoid of S2 are less susceptible than HIV-1 to the inhibitory effect of both human and equine SERINC5. We then identified the envelope glycoprotein of EIAV as a determinant that also modulates retroviral susceptibility to SERINC5, indicating that EIAV has a bimodal ability to counteract the host factor. S2 shares no sequence homology with other retroviral factors known to counteract SERINC5. Like the primate lentivirus Nef and the gammaretrovirus glycoGag, the accessory protein from EIAV is an example of a retroviral virulence determinant that independently evolved SERINC5-antagonizing activity. SERINC5 therefore plays a critical role in the interaction of the host with diverse retrovirus pathogens.
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Ross KA, Loyd H, Wu W, Huntimer L, Ahmed S, Sambol A, Broderick S, Flickinger Z, Rajan K, Bronich T, Mallapragada S, Wannemuehler MJ, Carpenter S, Narasimhan B. Hemagglutinin-based polyanhydride nanovaccines against H5N1 influenza elicit protective virus neutralizing titers and cell-mediated immunity. Int J Nanomedicine 2014; 10:229-43. [PMID: 25565816 PMCID: PMC4284014 DOI: 10.2147/ijn.s72264] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
H5N1 avian influenza is a significant global concern with the potential to become the next pandemic threat. Recombinant subunit vaccines are an attractive alternative for pandemic vaccines compared to traditional vaccine technologies. In particular, polyanhydride nanoparticles encapsulating subunit proteins have been shown to enhance humoral and cell-mediated immunity and provide protection upon lethal challenge. In this work, a recombinant H5 hemagglutinin trimer (H5₃) was produced and encapsulated into polyanhydride nanoparticles. The studies performed indicated that the recombinant H5₃ antigen was a robust immunogen. Immunizing mice with H5₃ encapsulated into polyanhydride nanoparticles induced high neutralizing antibody titers and enhanced CD4(+) T cell recall responses in mice. Finally, the H5₃-based polyanhydride nanovaccine induced protective immunity against a low-pathogenic H5N1 viral challenge. Informatics analyses indicated that mice receiving the nanovaccine formulations and subsequently challenged with virus were similar to naïve mice that were not challenged. The current studies provide a basis to further exploit the advantages of polyanhydride nanovaccines in pandemic scenarios.
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Affiliation(s)
- Kathleen A Ross
- Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | - Hyelee Loyd
- Animal Science, Iowa State University, Ames, IA, USA
| | - Wuwei Wu
- Animal Science, Iowa State University, Ames, IA, USA
| | - Lucas Huntimer
- Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA
| | - Shaheen Ahmed
- Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Anthony Sambol
- Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Scott Broderick
- Materials Science and Engineering, Iowa State University, Ames, IA, USA
| | | | - Krishna Rajan
- Materials Science and Engineering, Iowa State University, Ames, IA, USA
| | - Tatiana Bronich
- Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surya Mallapragada
- Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | | | | | - Balaji Narasimhan
- Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
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Ross KA, Loyd H, Wu W, Huntimer L, Wannemuehler MJ, Carpenter S, Narasimhan B. Structural and antigenic stability of H5N1 hemagglutinin trimer upon release from polyanhydride nanoparticles. J Biomed Mater Res A 2014; 102:4161-8. [DOI: 10.1002/jbm.a.35086] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 12/19/2013] [Accepted: 01/15/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Kathleen A. Ross
- Department of Chemical and Biological Engineering; Iowa State University; Ames Iowa 50011
| | - Hyelee Loyd
- Department of Animal Science; Iowa State University; Ames Iowa 50011
| | - Wuwei Wu
- Department of Animal Science; Iowa State University; Ames Iowa 50011
| | - Lucas Huntimer
- Department of Veterinary Microbiology and Preventive Medicine; Iowa State University; Ames Iowa 50011
| | - Michael J. Wannemuehler
- Department of Veterinary Microbiology and Preventive Medicine; Iowa State University; Ames Iowa 50011
| | - Susan Carpenter
- Department of Animal Science; Iowa State University; Ames Iowa 50011
| | - Balaji Narasimhan
- Department of Chemical and Biological Engineering; Iowa State University; Ames Iowa 50011
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Patel M, Giddings AM, Sechelski J, Olsen JC. High efficiency gene transfer to airways of mice using influenza hemagglutinin pseudotyped lentiviral vectors. J Gene Med 2013; 15:51-62. [PMID: 23319179 DOI: 10.1002/jgm.2695] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/29/2012] [Accepted: 01/02/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND A limitation to efficient lentivirus-mediated airway gene transfer is the lack of receptors to commonly used viral envelopes on the luminal surface of airway epithelia. The use of viral envelopes with natural tropism to the airway could be useful for overcoming this limitation. METHODS We investigated influenza hemagglutinin (HA) pseudotyped equine infectious anemia virus-derived lentiviral vector-mediated gene transfer to the airway epithelium of adult and newborn mice. For these studies, high-titer vectors were delivered by intranasal administration. In addition, we tested the feasibility of vector re-dosing to the nasal airway. RESULTS Delivery of high-titer HA pseudotyped lentiviral vectors by nasal administration to newborn mouse pups or adult mice results in the efficient transduction of airway epithelial cells in the nose, trachea, and lungs. In the nose, vector expression was predominant in the respiratory epithelium and was not observed in the olfactory epithelium. In the trachea and large airways of the lung, approximately 46% and 40%, respectively, of surface epithelial cells could be transduced. The efficiency of re-dosing to the nasal airway of mice was found to be dependent of the age of the animal when the first dose is administered, as well as the length of time between doses. CONCLUSIONS A single intranasal dose of concentrated influenza HA-pseudotyped lentiviral vector is sufficient for efficient gene transfer to the airways of mice. This is a promising result that could lead to the development of effective gene transfer reagents for the treatment of cystic fibrosis and other human lung diseases.
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Affiliation(s)
- Manij Patel
- Cystic Fibrosis/Pulmonary Research and Treatment Center, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Decreased infectivity of a neutralization-resistant equine infectious anemia virus variant can be overcome by efficient cell-to-cell spread. J Virol 2011; 85:10421-4. [PMID: 21752904 DOI: 10.1128/jvi.05349-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two variants of equine infectious anemia virus (EIAV) that differed in sensitivity to broadly neutralizing antibody were tested in direct competition assays. No differences were observed in the growth curves and relative fitness scores of EIAVs of principal neutralizing domain variants of groups 1 (EIAV(PND-1)) and 5 (EIAV(PND-5)), respectively; however, the neutralization-resistant EIAV(PND-5) variant was less infectious in single-round replication assays. Infectious center assays indicated similar rates of cell-to-cell spread, which was approximately 1,000-fold more efficient than cell-free infectivity. These data indicate that efficient cell-to-cell spread can overcome the decreased infectivity that may accompany immune escape and should be considered in studies assessing the relative levels of fitness among lentivirus variants, including HIV-1.
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Protective effects of broadly neutralizing immunoglobulin against homologous and heterologous equine infectious anemia virus infection in horses with severe combined immunodeficiency. J Virol 2011; 85:6814-8. [PMID: 21543497 DOI: 10.1128/jvi.00077-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using the equine infectious anemia virus (EIAV) lentivirus model system, we previously demonstrated protective effects of broadly neutralizing immune plasma in young horses (foals) with severe combined immunodeficiency (SCID). However, in vivo selection of a neutralization-resistant envelope variant occurred. Here, we determined the protective effects of purified immunoglobulin with more potent broadly neutralizing activity. Overall, protection correlated with the breadth and potency of neutralizing activity in vitro. Four of five SCID foals were completely protected against homologous challenge, while partial protection occurred following heterologous challenge. These results support the inclusion of broadly neutralizing antibodies in lentivirus control strategies.
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An equine infectious anemia virus variant superinfects cells through novel receptor interactions. J Virol 2008; 82:9425-32. [PMID: 18667522 DOI: 10.1128/jvi.01142-08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wild-type strains of equine infectious anemia virus (EIAV) prevent superinfection of previously infected cells. A variant strain of virus that spontaneously arose during passage, EIAV(vMA-1c), can circumvent this mechanism in some cells, such as equine dermis (ED) cells, but not in others, such as equine endothelial cells. EIAV(vMA-1c) superinfection of ED cells results in a buildup of unintegrated viral DNA and rapid killing of the cell monolayer. Here, we examined the mechanism of resistance that is used by EIAV to prevent superinfection and explored the means by which EIAV(vMA-1c) overcomes this restriction. We found that the cellular receptor used by EIAV, equine lentivirus receptor 1 (ELR1), remains on the surface of cells chronically infected with EIAV, suggesting that wild-type EIAV interferes with superinfection by masking ELR1. The addition of soluble wild-type SU protein to the medium during infection blocked infection by wild-type strains of virus, implicating SU as the viral protein responsible for interfering with virion entry into previously infected cells. Additionally, interference of wild-type EIAV binding to ELR1 by the addition of either anti-ELR1 antibodies or the ELR1 ectodomain prevented entry of the wild-type strains of EIAV into two permissive cell populations. Many of these same interference treatments prevented EIAV(vMA-1c) infection of endothelial cells but only modestly affected the ability of EIAV(vMA-1c) to enter and kill previously infected ED cells. These findings indicate that EIAV(vMA-1c) retains the ability to use ELR1 for entry and suggest that this virus can interact with an additional, unidentified receptor to superinfect ED cells.
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