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Identifying the Role of E2 Domains on Alphavirus Neutralization and Protective Immune Responses.

Weger-Lucarelli J, Aliota MT, Kamlangdee A, Osorio JE - PLoS Negl Trop Dis (2015)

Bottom Line: The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response.Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans.Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.

ABSTRACT

Background: Chikungunya virus (CHIKV) and other alphaviruses are the etiologic agents of numerous diseases in both humans and animals. Despite this, the viral mediators of protective immunity against alphaviruses are poorly understood, highlighted by the lack of a licensed human vaccine for any member of this virus genus. The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response. Although envelope protein domains have been studied for vaccine and neutralization in flaviviruses, their role in alphaviruses is less characterized. Here, we describe the role of the alphavirus E2 domains in neutralization and protection through the use of chimeric viruses.

Methodology/principal findings: Four chimeric viruses were constructed in which individual E2 domains of CHIKV were replaced with the corresponding domain from Semliki Forest virus (SFV) (ΔDomA/ΔDomB/ΔDomC/ ΔDomA+B). Vaccination studies in mice (both live and inactivated virus) revealed that domain B was the primary determinant of neutralization. Neutralization studies with CHIKV immune serum from humans were consistent with mouse studies, as ΔDomB was poorly neutralized.

Conclusions/significance: Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans. Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes. This study provides new insight into the role of alphavirus E2 domains on neutralization determinants and may be useful for the design of novel therapeutic technologies.

No MeSH data available.


Related in: MedlinePlus

Genome organization of chimeric CHIKV/SFV viruses.Genome organization of chimeric CHIKV/SFV viruses. The different domains of E2 from SFV were inserted into the CHIKV genome in the corresponding position in individual constructs using a PCR based cloning approach. Each virus expressed the GFP protein under control of a second sub-genomic promoter. Red portions of the E2 represent genetic sequences of SFV whereas CHIKV is shown in blue.
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pntd.0004163.g001: Genome organization of chimeric CHIKV/SFV viruses.Genome organization of chimeric CHIKV/SFV viruses. The different domains of E2 from SFV were inserted into the CHIKV genome in the corresponding position in individual constructs using a PCR based cloning approach. Each virus expressed the GFP protein under control of a second sub-genomic promoter. Red portions of the E2 represent genetic sequences of SFV whereas CHIKV is shown in blue.

Mentions: CHIKV/SFV chimeras were constructed using a PCR-based cloning approach which allowed precise manipulation of DNA sequences without relying on restriction enzymes [27]. In total, four chimeric viruses were constructed (referred to as ΔDomA/ΔDomB/ΔDomC/ΔDomA+B) in which each domain(s) was replaced in a CHIKV backbone with the corresponding domain(s) from SFV (Fig 1). In vitro and in vivo characterization was performed and it was determined that each virus was viable in cell culture, mice and mosquitoes, although different phenotypes were observed (Weger-Lucarelli et al. manuscript submitted).


Identifying the Role of E2 Domains on Alphavirus Neutralization and Protective Immune Responses.

Weger-Lucarelli J, Aliota MT, Kamlangdee A, Osorio JE - PLoS Negl Trop Dis (2015)

Genome organization of chimeric CHIKV/SFV viruses.Genome organization of chimeric CHIKV/SFV viruses. The different domains of E2 from SFV were inserted into the CHIKV genome in the corresponding position in individual constructs using a PCR based cloning approach. Each virus expressed the GFP protein under control of a second sub-genomic promoter. Red portions of the E2 represent genetic sequences of SFV whereas CHIKV is shown in blue.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608762&req=5

pntd.0004163.g001: Genome organization of chimeric CHIKV/SFV viruses.Genome organization of chimeric CHIKV/SFV viruses. The different domains of E2 from SFV were inserted into the CHIKV genome in the corresponding position in individual constructs using a PCR based cloning approach. Each virus expressed the GFP protein under control of a second sub-genomic promoter. Red portions of the E2 represent genetic sequences of SFV whereas CHIKV is shown in blue.
Mentions: CHIKV/SFV chimeras were constructed using a PCR-based cloning approach which allowed precise manipulation of DNA sequences without relying on restriction enzymes [27]. In total, four chimeric viruses were constructed (referred to as ΔDomA/ΔDomB/ΔDomC/ΔDomA+B) in which each domain(s) was replaced in a CHIKV backbone with the corresponding domain(s) from SFV (Fig 1). In vitro and in vivo characterization was performed and it was determined that each virus was viable in cell culture, mice and mosquitoes, although different phenotypes were observed (Weger-Lucarelli et al. manuscript submitted).

Bottom Line: The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response.Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans.Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.

ABSTRACT

Background: Chikungunya virus (CHIKV) and other alphaviruses are the etiologic agents of numerous diseases in both humans and animals. Despite this, the viral mediators of protective immunity against alphaviruses are poorly understood, highlighted by the lack of a licensed human vaccine for any member of this virus genus. The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response. Although envelope protein domains have been studied for vaccine and neutralization in flaviviruses, their role in alphaviruses is less characterized. Here, we describe the role of the alphavirus E2 domains in neutralization and protection through the use of chimeric viruses.

Methodology/principal findings: Four chimeric viruses were constructed in which individual E2 domains of CHIKV were replaced with the corresponding domain from Semliki Forest virus (SFV) (ΔDomA/ΔDomB/ΔDomC/ ΔDomA+B). Vaccination studies in mice (both live and inactivated virus) revealed that domain B was the primary determinant of neutralization. Neutralization studies with CHIKV immune serum from humans were consistent with mouse studies, as ΔDomB was poorly neutralized.

Conclusions/significance: Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans. Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes. This study provides new insight into the role of alphavirus E2 domains on neutralization determinants and may be useful for the design of novel therapeutic technologies.

No MeSH data available.


Related in: MedlinePlus