Eastern equine encephalitis virus (EEEV), an Alphavirus in the family Togaviridae, is classified in Category B of the NIH Priority Pathogens List, and as a high consequence livestock pathogen by the USDA because it is highly lethal for humans and equines, and because effective vaccines and therapies are lacking, EEEV. The formalin-inactivated vaccine strain of EEEV is not suitable for wide-scale human use due to poor immunogenicity and possible residual virulence. Clearly alternative strategies for vaccine production are required. Our long-term goal is to develop a live-attenuated virus vaccine with sufficient degree of attenuation to be safe for human populations. The objective of the proposed research is the rational design of attenuated strains via the selective deletion (or disabling) of innate immune evasion properties. This will be based on the hypothesis that EEEV possesses mechanism(s) to antagonize the interferon alpha/beta (IFN-a/b) response elicited by infected dendritic cells (DCs) which can be disabled to attenuate the virus and enhance the immune response. Several key observations lead us to believe that the relative sensitivity of alphaviruses to IFN-a/b-mediated antiviral activity is a primary determinant of virulence and attenuation. Our studies with Sindbis virus (SB) have revealed that this alphavirus with little or no ability to evade or antagonize mammalian IFN-a/b is extremely attenuated in mice whereas, a mouse-virulent alphavirus, such as Venezuelan equine encephalitis virus (VEEV), is relatively much more resistant to the antiviral activity of IFN-a/b. Mutants of VEEV with increased sensitivity to IFN-a/b are attenuated in mice. As EEEV also remains virulent in the face of a functional IFN-a/b response, and alphavirus virulence appears to be strongly correlated with IFN-a/b resistance, we hypothesize that EEEV evades and/or disables components of the IFN-a/b response. We propose to gain a better understanding of the way(s) in which EEEV overcomes the antiviral activity of IFN-a/b by comparison to SB with the goal of developing an IFN-a/b sensitive, live-attenuated EEEV strain by determining which IFN-a/b-mediated pathway(s) are antagonized or evaded by EEEV. Specifically we will determine relative to SB whether EEEV is able to: i) antagonize/resist antiviral effectors; ii) avoid/suppress induction of IFN-a/b; and/or iii) suppress IFN-a/b- mediated signaling. We anticipate that these studies will provide the foundation for future identification and disablement of EEEV-encoded product(s) that antagonize IFN-a/b activity. Anticipated product(s): Our long-term goal is the rational design of attenuated alphavirus strains with sufficient degree of attenuation to be safe for human populations via the selective inactivation of innate immune evasion properties. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI069158-01
Application #
7082476
Study Section
Immunity and Host Defense Study Section (IHD)
Program Officer
Repik, Patricia M
Project Start
2006-03-01
Project End
2008-02-29
Budget Start
2006-03-01
Budget End
2007-02-28
Support Year
1
Fiscal Year
2006
Total Cost
$217,500
Indirect Cost
Name
Louisiana State University Hsc Shreveport
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
095439774
City
Shreveport
State
LA
Country
United States
Zip Code
71103
Gardner, Christina L; Burke, Crystal W; Higgs, Stephen T et al. (2012) Interferon-alpha/beta deficiency greatly exacerbates arthritogenic disease in mice infected with wild-type chikungunya virus but not with the cell culture-adapted live-attenuated 181/25 vaccine candidate. Virology 425:103-12
Yin, Jun; Gardner, Christina L; Burke, Crystal W et al. (2009) Similarities and differences in antagonism of neuron alpha/beta interferon responses by Venezuelan equine encephalitis and Sindbis alphaviruses. J Virol 83:10036-47
Burke, Crystal W; Gardner, Christina L; Steffan, Joshua J et al. (2009) Characteristics of alpha/beta interferon induction after infection of murine fibroblasts with wild-type and mutant alphaviruses. Virology 395:121-32
Gardner, Christina L; Yin, Jun; Burke, Crystal W et al. (2009) Type I interferon induction is correlated with attenuation of a South American eastern equine encephalitis virus strain in mice. Virology 390:338-47
Meier, Kathryn C; Gardner, Christina L; Khoretonenko, Mikhail V et al. (2009) A mouse model for studying viscerotropic disease caused by yellow fever virus infection. PLoS Pathog 5:e1000614
Tesfay, Mulu Z; Yin, Jun; Gardner, Christina L et al. (2008) Alpha/beta interferon inhibits cap-dependent translation of viral but not cellular mRNA by a PKR-independent mechanism. J Virol 82:2620-30
Gardner, Christina L; Burke, Crystal W; Tesfay, Mulu Z et al. (2008) Eastern and Venezuelan equine encephalitis viruses differ in their ability to infect dendritic cells and macrophages: impact of altered cell tropism on pathogenesis. J Virol 82:10634-46
Zhang, Yugen; Burke, Crystal W; Ryman, Kate D et al. (2007) Identification and characterization of interferon-induced proteins that inhibit alphavirus replication. J Virol 81:11246-55