Comparative analysis of expression, immunogenicity, and safety profiles between linear and circular RNA vaccine platforms

Jun 12, 2026Molecular therapy. Nucleic acids

Comparison of production, immune response, and safety between linear and circular RNA vaccines

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mRNA Technology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Circular RNA demonstrated prolonged expression compared to linear RNA in this comparison study.

Circular RNA with unmodified nucleotides and linear RNA with modified nucleotides produced higher antibody levels than linear RNA with unmodified nucleotides.
Cell-mediated immune responses were slightly higher for linear RNA with modified nucleotides and linear RNA with unmodified nucleotides compared to circular RNA.
All RNA types resulted in a decrease in certain blood cell counts shortly after high-dose injection in mice.
Platelet counts decreased more significantly with linear RNA containing unmodified nucleotides and circular RNA than with linear RNA containing modified nucleotides.
All observed changes in blood cell counts returned to normal levels by day 14 post-vaccination.

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mRNA vaccines have revolutionized development and continue to advance through clinical and research applications. Circular RNA is emerging as a promising alternative to linear RNA. However, no direct comparison has identified the optimal RNA platform for mRNA-based drug development. This study compares linear and circular RNA platformsand, focusing on expression dynamics, immune responses, and safety. In terms of expression efficiency, the circular RNA showed prolonged expression compared to linear RNA. The immunogenicity was evaluated using influenza HA as an antigen. In humoral immune response, linear RNA with modified nucleosides (Lin-m1Ψ) and circular RNA with unmodified nucleosides (Circ-WT) showed higher neutralizing antibody titers than linear RNA with unmodified nucleosides (Lin-WT). Lin-m1Ψ and Lin-WT induced slightly higher cell-mediated immune responses than Circ-WT. In mice, all RNA types showed a decrease in reticulocytes, monocytes, and alkaline phosphatase on day 2 following high-dose intramuscular injection. Furthermore, Lin-WT and Circ-WT showed greater decreases in platelets than Lin-m1Ψ. However, these changes recovered to normal by day 14 post-vaccination in all groups. These findings provide insights into developing RNA-based immunotherapies and selecting suitable RNA platforms for various applications, including preventive and therapeutic vaccines as well as protein-replacement therapies. in vitro in vivo