The development of a vaccine against human cytomegalovirus (HCMV) is a major public health priority. Of particular urgency is the need to protect newborn infants from the devastating consequences of congenital HCMV infection, including mental retardation, cerebral palsy, and deafness. Recently, a subunit vaccine based on recombinant HCMV glycoprotein B (gB) showed efficacy in a clinical trial. However, it is not clear that a vaccine based on a single HCMV protein will provide robust, long-term protection, particularly for women in their childbearing years. A potential significant advantage of the live, attenuated approach to HCMV vaccines is that such vaccines could elicit an immune response that mimics natural immunity and hence provide broader protection to a wide variety of virus-encoded targets of the host immune response. However, such vaccines carry the theoretical risk of establishing latency, reactivating under conditions of immune suppression, or causing chronic HCMV-associated diseases. An approach to generate an immunogenic, yet safe live vaccine is the deletion of viral genes that subvert host defense mechanisms to infection. Using the guinea pig model of congenital CMV infection, we propose to test this approach by targeting viral genes that subvert two key host defenses: MHC I homolog genes (NK cell evasins) and protein kinase R (PKR) evasins. In the previous funding period, we demonstrated efficacy and safety of a recombinant GPCMV vaccine which had a genomic deletion of a block of MHC I homologs. We propose to identify the key viral gene involved in this attenuation and to test our hypothesis that this gene product evades host defenses by inhibition of the NK cell response (aim 1). We hypothesize this virus will demonstrate superiority immunogenicity over wild-type virus, as assessed by cytokine response, CD8+ response, and antibody titer. A recombinant virus deleted of the MHC I function, ?(MHC, will be evaluated for attenuation in animals, and immune mechanisms will be confirmed by immune assays and NK depletion studies. In the previous funding period we have also identified a GPCMV gene involved in the inactivation of PKR. We propose to characterize this and other PKR evasins (aim 2) toward the goal of generating a deletion virus incapable of inhibiting the PKR response ((PKR). We will combine PKR and MHC mutations in a single attenuated virus construct that we predict will yield a safe, highly attenuated vaccine with improved immunogenicity. Despite tight innate immune control, this (MHC/(PKR construct is hypothesized to elicit strong, long-lasting protective immunity. This concept will be further tested in the GPCMV congenital infection model by evaluating and comparing the (MHC and (MHC/(PKR vaccines (aim 3). We hypothesize these vaccines will demonstrate equal or superior protection to infection with wild-type (control) virus against congenital infection and disease. By identifying optimal attenuated vaccine strategies in the GPCMV model, the translational prospect of genetically designing a vaccine for HCMV that has strong immunogenicity and improved safety will emerge.

Public Health Relevance

Infectious agents can cause birth defects in newborn infants, and the most common of these infectious diseases in the United States is human cytomegalovirus (CMV). A vaccine given to a woman before pregnancy would likely prevent CMV from causing injury to the fetus and newborn infant. An attractive approach is to design a vaccine that is attenuated, meaning that the vaccine is very similar to the natural virus itself, but unable to cause disease. However, such a vaccine must be safe, so there needs to be more knowledge gained about how to modify the virus so that it is very safe, but still able to induce a strong immune response. These studies use an animal model in guinea pigs to generate this new knowledge. These studies will examine ways to engineer the CMV virus, by deleting genes that contribute to its ability to evade immune clearance, in order to design a safe vaccine that is also highly protective for the developing fetus.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD044864-08
Application #
8238125
Study Section
Vaccines Against Microbial Diseases (VMD)
Program Officer
Higgins, Rosemary
Project Start
2003-06-10
Project End
2016-01-31
Budget Start
2012-02-01
Budget End
2013-01-31
Support Year
8
Fiscal Year
2012
Total Cost
$461,007
Indirect Cost
$83,491
Name
University of Minnesota Twin Cities
Department
Pediatrics
Type
Schools of Medicine
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Schleiss, Mark R; McAllister, Shane; ArmiƩn, Anibal G et al. (2014) Molecular and biological characterization of a new isolate of guinea pig cytomegalovirus. Viruses 6:448-75
Gillis, Peter A; Hernandez-Alvarado, Nelmary; Gnanandarajah, Josephine S et al. (2014) Development of a novel, guinea pig-specific IFN-? ELISPOT assay and characterization of guinea pig cytomegalovirus GP83-specific cellular immune responses following immunization with a modified vaccinia virus Ankara (MVA)-vectored GP83 vaccine. Vaccine 32:3963-70
McAllister, Shane C; Schleiss, Mark R (2014) Prospects and perspectives for development of a vaccine against herpes simplex virus infections. Expert Rev Vaccines 13:1349-60
Gnanandarajah, Josephine S; Gillis, Peter A; Hernandez-Alvarado, Nelmary et al. (2014) Identification by mass spectrometry and immune response analysis of guinea pig cytomegalovirus (GPCMV) pentameric complex proteins GP129, 131 and 133. Viruses 6:727-51
Schleiss, Mark R; Choi, K Yeon; Anderson, Jodi et al. (2014) Glycoprotein B (gB) vaccines adjuvanted with AS01 or AS02 protect female guinea pigs against cytomegalovirus (CMV) viremia and offspring mortality in a CMV-challenge model. Vaccine 32:2756-62
Yang, Dongmei; Alam, Zohaib; Cui, Xiaohong et al. (2014) Complete genome sequence of cell culture-attenuated Guinea pig cytomegalovirus cloned as an infectious bacterial artificial chromosome. Genome Announc 2:
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Bierle, Craig J; Semmens, Kathryn M; Geballe, Adam P (2013) Double-stranded RNA binding by the human cytomegalovirus PKR antagonist TRS1. Virology 442:28-37
Pfister, K M; Schleiss, M R; Reed, R C et al. (2013) Non-immune hydrops fetalis caused by herpes simplex virus type 2 in the setting of recurrent maternal infection. J Perinatol 33:817-20
Verghese, Priya S; Schleiss, Mark R (2013) Letermovir Treatment of Human Cytomegalovirus Infection Antiinfective Agent. Drugs Future 38:291-298

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