New Publication from the Researchers at IBT

Efforts to develop effective vaccines against Staphylococcus aureus (S. aureus) have been largely unsuccessful, in part due to the variety of virulence factors produced by this organism. Recently, researchers lead by Dr. Rajan Adhikari at IBT have published a paper entitled 'Novel Structurally Designed Vaccine for S. aureus ?-Hemolysin: Protection against Bacteremia and Pneumonia' in PLoS ONE , an international, peer-reviewed, open-access, online publication. S. aureus alpha-hemolysin (Hla) is a pore-forming toxin expressed by most S. aureus strains and reported to play a key role in the pathogenesis of skin and soft tissue infections and pneumonia.

This article describes a novel recombinant subunit vaccine candidate for Hla, rationally designed based on the heptameric crystal structure. The vaccine candidate, called AT-62aa, has shown significant protection against pneumonia and is the first to be reported to reduce bacterial dissemination and to provide protection in a sepsis model of S. aureus infection. Antibodies to AT-62aa and sera from vaccinated mice effectively neutralized the toxin in vitro and inhibited the formation of Hla heptamers, suggesting antibody-mediated neutralization as the primary mechanism of action. This remarkable efficacy makes the Hla-based vaccine a prime candidate for inclusion in future multivalent S. aureus vaccines. Furthermore, identification of protective epitopes within AT-62aa could lead to novel immunotherapies for S. aureus infection.

Publications

Immunization-Elicited Broadly Protective Antibody Reveals Ebolavirus Fusion Loop as a Site of Vulnerability.  Zhao X, Howell KA, He S, Brannan JM, Wec AZ, Davidson E, Turner HL, Chiang CI, Lei L, Fels JM, Vu H, Shulenin S, Turonis AN, Kuehne AI, Liu G, Ta M, Wang Y, Sundling C, Xiao Y, Spence JS, Doranz BJ, Holtsberg FW, Ward AB, Chandran K, Dye JM, Qiu X, Li Y, Aman MJ.  Cell. 2017 May 18;169(5):891-904.e15. doi: 10.1016/j.cell.2017.04.038.

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Cooperativity Enables Non-neutralizing Antibodies to Neutralize Ebolavirus.  Howell KA, Brannan JM, Bryan C, McNeal A, Davidson E, Turner HL, Vu H, Shulenin S, He S, Kuehne A, Herbert AS, Qiu X, Doranz BJ, Holtsberg FW, Ward AB, Dye JM, Aman MJ.  Cell Rep. 2017 Apr 11;19(2):413-424. doi: 10.1016/j.celrep.2017.03.049.

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Protective efficacy of a novel alpha hemolysin subunit vaccine (AT62) against Staphylococcus aureus skin and soft tissue infections.  Adhikari RP, Thompson CD, Aman MJ, Lee JC.  Vaccine. 2016 Dec 7;34(50):6402-6407. doi:10.1016/j.vaccine.2016.09.061. Epub 2016 Nov 12.
 

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Safety and Immunogenicity of a Parenterally Administered, Structure-Based Rationally Modified Recombinant Staphylococcal Enterotoxin B Protein Vaccine, STEBVax. Chen WH, Pasetti MF, Adhikari RP, Baughman H, Douglas R, El-Khorazaty J, Greenberg N, Holtsberg FW, Liao GC, Reymann MK, Wang X, Warfield KL, Aman MJ. Clin Vaccine Immunol. 2016 Dec 5;23(12):918-925. Print 2016 Dec.
 

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A "Trojan Horse" Bispecific Antibody Strategy for Broad Protection against Ebolaviruses. Wec, A.Z. Nyakatura, E.K. Herbert, A.S. Howell, K.A. Holtsberg, F.W. Bakken, R.R. Mittler, E. Christin, J.R. Shulenin, S. Jangra, R.K. Bharrhan, S. Kuehne, A.I. Bornholdt, Z.A. Flyak, A.I. Saphire, E. Crowe Jr., J.E. Aman, M.J. Dye, J.M. Lai, J.R. Chandran, K. (2016) Science 8(2016). doi: 10.1126/science.aag3267

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Feverish Quest for Ebola Immunotherapy: Straight or Cocktail?  Aman, M.J. Saphire, EO. (2016) Trends Microbiol 10(1016). pii: SD966-842X(16)30049-X

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Zika Virus: A New Animal Model for an Arbovirus.  Aman, M.J. Kashanchi, F. (2016) PLoS Negl Trop Dis 10(5): e0004702. doi:10.1371/journal.pntd.0004702

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Virus-Like Particle Vaccination Protects Nonhuman Primates from Lethal Aerosol Exposure with Marburgvirus (VLP Vaccination Protects Macaques against Aerosol Challenges).  Dye JM, Warfield KL, Wells JB, Unfer RC, Shulenin S, Vu H, Nichols DK, Aman MJ, Bavari S. Viruses. 2016 Apr 8;8(4). pii: E94. doi: 10.3390/v8040094

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Antibody Treatment of Ebola and Sudan Virus Infection via a Uniquely Exposed Epitope within the Glycoprotein Receptor-Binding Site.  Howell KA, Qiu X, Brannan JM, Bryan C, Davidson E, Holtsberg FW, Wec AZ, Shulenin S, Biggins JE, Douglas R, Enterlein SG, Turner HL, Pallesen J, Murin CD, He S, Kroeker K, Vu H, Herbert AS, Fusco ML, Nyakatura EK, Lai JR, Keck ZY, Foung SKH, Saphire EO, Zeitlin L, Ward AB, Chandran K, Doranz BJ, Kobinger GP, Dye JM, Aman MJ. (2016) Cell Reports 15, 1–13.

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Monoclonal antibody therapy for Junin virus infection.  Zeitlin L, Geisbert JB, Deer DJ, Fenton KA, Bohorov O, Bohorova N, Goodman C, Kim D, Hiatt A, Pauly MH, Velasco J, Whaley KJ, Altmann F, Gruber C, Steinkellner H, Honko AN, Kuehne AI, Aman MJ, Sahandi S, Enterlein S, Zhan X, Enria D, Geisbert TW. Proc Natl Acad Sci U S A. 2016 Apr 19;113(16):4458-63.

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Aman MJ, Chasing Ebola through the Endosomal Labyrinth:, MBio, 2016, 7(2):e00346-16

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Holtsberg et al., Pan-ebolavirus and Pan-filovirus Mouse Monoclonal Antibodies: Protection against Ebola and Sudan Viruses, J Virol, 2014

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Keck et al., Macaque Monoclonal Antibodies Targeting Novel Conserved Epitopes within Filovirus Glycoprotein, J Virol, 2014

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Adhikari et al., Antibodies to S. aureus LukS-PV Attenuated Subunit Vaccine Neutralize a Broad Spectrum of Canonical and Non-Canonical Bicomponent Leukotoxin Pairs, PLoS One, 2015

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Fusco et al., Protective mAbs and Cross-Reactive mAbs Raised by Immunization with Engineered Marburg Virus GPs, PLoS Pathog, 2015

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Warfield et al., Homologous and heterologous protection of nonhuman primates by Ebola and Sudan virus-like particles, PLoS One, 2015

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Sully et al., A tripartite cocktail of chimeric monoclonal antibodies passively protects mice against ricin, staphylococcal enterotoxin B and Clostridium perfringens epsilon toxin, Toxicon, 2014

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Warfield et al., Vaccinating captive chimpanzees to save wild chimpanzees, Proc Natl Acad Sci USA, 2014

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Aman and Adhikari, Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy, Toxins, 2014

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Karauzum et al., Structurally designed attenuated subunit vaccines for S. aureus LukS-PV and LukF-PV confer protection in a mouse bacteremia model, PLoS One, 2013

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Adhikari et al., Lower antibody levels to Staphylococcus aureus exotoxins are associated with sepsis in hospitalized adults with invasive S. aureus infections, J Infect Dis, 2012

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Adhikari et al., Novel structurally designed vaccine for S. aureus α-hemolysin: protection against bacteremia and pneumonia, PLoS One, 2012.

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