Replicon RNA Viral Vectors as Vaccines

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Single-stranded RNA (ssRNA) viruses, both positive and negative polarity, are explored as vaccine vectors.
• Various ssRNA viruses like alphaviruses, flaviviruses, measles virus, and rhabdoviruses have been engineered for antigen expression.

Approach:

• Engineered ssRNA viruses, including replicon RNA vectors, virus-like particles, and naked RNA, were used for immunization.
• Delivery systems like liposomes were employed to enhance the targeting and efficacy of RNA vectors.
• Immunization strategies were tested in diverse animal models (mice, chicken, pigs, primates) and clinical trials.

Key Points:

• Administration of replicon RNA vectors elicited robust immune responses and neutralizing antibodies in animal models.
• Immunization with these RNA-based platforms conferred protection against infectious agents and tumor cells.
• Both prophylactic and therapeutic applications were demonstrated, particularly in cancer immunotherapy.

Conclusions:

• Self-replicating RNA virus immunization offers high, transient antigen expression, leading to potent neutralizing antibody responses.
• These RNA-based vaccines provide protection against lethal challenges under safe conditions.
• Replicon RNA vectors have advanced to clinical trials, indicating their therapeutic potential.