Kunjin virus replicon vaccine vectors induce protective CD8+ T-cell immunity

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Self-replicating RNA (replicon) vaccine vectors offer a promising platform for inducing robust immune responses.
• The Australian flavivirus Kunjin (KUN) has been explored as a basis for developing novel vaccine vectors.
• CD8+ T-cell responses are crucial for controlling viral infections and cancer.

Purpose of the Study:

• To evaluate the capacity of Kunjin (KUN) replicon vaccine vectors to elicit protective alphabeta CD8+ T-cell responses.
• To compare the immunogenicity of KUN replicons delivered via different vaccine modalities.
• To assess the protective efficacy of KUN replicon vaccines against viral and tumor challenges.

Main Methods:

• KUN replicons encoding a model immunogen were prepared as naked RNA, DNA-based plasmids for in vivo transcription, or virus-like particles.
• Mice were immunized with one of the three KUN replicon vaccine formulations.
• CD8+ T-cell responses were quantified and compared to controls.
• Vaccinated mice were challenged with recombinant vaccinia virus and B16 tumor cells to assess protection.

Main Results:

• A single immunization with any KUN replicon vaccine modality induced comparable CD8+ T-cell responses to recombinant vaccinia virus.
• DNA-based KUN replicons elicited robust CD8+ T-cell responses at significantly lower doses than conventional DNA vaccines.
• Naked RNA KUN replicon immunization conferred protection against viral challenge and tumor growth.

Conclusions:

• Kunjin (KUN) replicon vectors are effective in inducing protective CD8+ T-cell responses.
• These vectors demonstrate potential for developing potent antiviral and anticancer vaccines.
• The KUN replicon system offers a versatile and efficient platform for vaccine development.