A chikungunya fever vaccine utilizing an insect-specific virus platform

Area of Science:

• Vaccinology
• Virology
• Structural Biology

Background:

• Traditional vaccine development faces tradeoffs between immunogenicity and safety.
• Live-attenuated vaccines offer strong immunity but pose safety concerns, while inactivated vaccines are safer but less immunogenic.
• Existing vaccine strategies necessitate multiple doses and boosters, highlighting a need for improved platforms.

Purpose of the Study:

• To develop a novel vaccine platform overcoming traditional immunogenicity and safety tradeoffs.
• To engineer a chimeric virus based on Eilat virus (EILV) and chikungunya virus (CHIKV) for chikungunya fever (CHIKF) vaccine development.
• To evaluate the safety and immunogenicity of the EILV/CHIKV vaccine candidate in preclinical models.

Main Methods:

• Development of a recombinant EILV/CHIKV vaccine using an EILV cDNA clone and CHIKV structural proteins.
• Structural characterization of the recombinant virus using single-particle cryo-electron microscopy.
• Assessment of viral replication competence, immunogenicity (neutralizing antibodies), and protective efficacy in mouse and nonhuman primate models.

Main Results:

• The recombinant EILV/CHIKV was structurally identical to wild-type CHIKV and mimicked early replication stages without productive replication, ensuring safety.
• A single dose induced rapid (4 days) and long-lasting (>290 days) neutralizing antibodies in mice, conferring complete protection.
• In nonhuman primates, EILV/CHIKV elicited robust immunity, preventing viremia and fever.

Conclusions:

• The Eilat virus (EILV) platform offers a safe and effective vaccine strategy by leveraging insect-specific viruses.
• The EILV/CHIKV candidate demonstrates potential for a single-dose vaccine against chikungunya fever.
• This represents a novel application of insect-specific viruses in vaccine development, with broad vaccinology implications.