Cytomegalovirus (CMV)-based vectors are uniquely capable of inducing long-term effector memory T cell responses and escaping vector-specific immunity. However, fully replicative vectors are unlikely to be approved for human use given the pathogenic potential of CMV, particularly in pregnant women and immunocompromised individuals. A central goal is therefore to increase vector safety while maintaining immunogenicity and efficacy. In this project, we will define how acute and persistent replication correlates with the ability of rhesus CMV to induce a T cell response to simian immunodeficiency virus (SIV). Preliminary data suggest that severely attenuated RhCMV can still induce CMV-specific immune responses in sero-negative animals consistent with persistent antigen production. Unlike the parental vector however, the such low-cycle vectors do not seem to be secreted from inoculated animals. Importantly, low-cycle vectors expressing simian immunedeficiency virus (SIV) antigens super-infect sero-positive animals and induce an SIV-specific T cell response suggesting retention of immunogenicity. In three specific aims we will determine the extent to which vectors can be rendered replication-incompetent without sacrificing immunogenicity and the pathogenicity of such vectors in the immunocompromised.
Specific Aim 1 is to further reduce the ability of RhCMV/SIV vectors to replicate by constructing single-cycle vectors. In addition, we will construct vectors whose replication can be externally controlled thus allowing us to study the role of viral replication and spreading for the establishment and maintenance of persistent antigen production and T cell stimulation.
Specific Aim 2 is to determine the pathogenicity of replication-deficient vectors in an animal model of congenital infection. A further aim is to compare their ability to induce robust SIV-specific effector memory T cell responses in sero-positive animals.
Specific Aim 3 is to generate vectors combining the lowest pathogenicity with the highest immunogenicity for efficacy studies and to confirm that corresponding human CMV vectors are attenuated in a novel animal model of latent infection. Thus, we expect that the attenuation strategy developed here will be directly translatable into HCMV/HIV vectors.

Public Health Relevance

The goal of this project is to increase the safety of an HIV vaccine delivered by cytomegalovirus. This will be achieved by removing essential genes from the cytomegalovirus genome thus generating a replication-deficient vaccine. We will test whether the resulting vaccine is safe while retaining the advantageous immunizing characteristics of the replicating vaccine.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Program Projects (P01)
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Special Emphasis Panel (ZAI1-BP-A)
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Oregon Health and Science University
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Walters, Lucy C; Harlos, Karl; Brackenridge, Simon et al. (2018) Pathogen-derived HLA-E bound epitopes reveal broad primary anchor pocket tolerability and conformationally malleable peptide binding. Nat Commun 9:3137
Child, Stephanie J; Hickson, Sarah E; Bayer, Avraham et al. (2018) Antagonism of the Protein Kinase R Pathway in Human Cells by Rhesus Cytomegalovirus. J Virol 92:
McMichael, Andrew J; Picker, Louis J (2018) Corrigendum to 'Unusual antigen presentation offers new insight into HIV vaccine design' [Curr Opin Immunol 46 (2017) 75-81]. Curr Opin Immunol 53:217
Wu, Helen L; Wiseman, Roger W; Hughes, Colette M et al. (2018) The Role of MHC-E in T Cell Immunity Is Conserved among Humans, Rhesus Macaques, and Cynomolgus Macaques. J Immunol 200:49-60
Früh, Klaus; Picker, Louis (2017) CD8+ T cell programming by cytomegalovirus vectors: applications in prophylactic and therapeutic vaccination. Curr Opin Immunol 47:52-56
McMichael, Andrew J; Picker, Louis J (2017) Unusual antigen presentation offers new insight into HIV vaccine design. Curr Opin Immunol 46:75-81
Hansen, Scott G; Wu, Helen L; Burwitz, Benjamin J et al. (2016) Broadly targeted CD8? T cell responses restricted by major histocompatibility complex E. Science 351:714-20
Hansen, Scott G; Sacha, Jonah B; Hughes, Colette M et al. (2013) Cytomegalovirus vectors violate CD8+ T cell epitope recognition paradigms. Science 340:1237874
Hansen, Scott G; Piatak Jr, Michael; Ventura, Abigail B et al. (2013) Immune clearance of highly pathogenic SIV infection. Nature 502:100-4
Masopust, David; Picker, Louis J (2012) Hidden memories: frontline memory T cells and early pathogen interception. J Immunol 188:5811-7

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