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Antigenic determinants

DNA Vaccines Show Promise in Eliciting Strong Cross- Reactive T Cell Responses Against Omicron Variants

Strategic Insights

— 1 min read

Researchers at Huazhong University of Science and Technology have developed DNA vaccines encoding the spike protein of both the ancestral virus and Omicron variants, which demonstrated strong cross-reactive T cell responses in mice. The study found that only a limited number of mice vaccinated with the DNA vaccine targeting the original spike protein exhibited weak cross-reactivity with Omicron variants. In contrast, DNA vaccines encoding spike proteins from Omicron variants successfully elicited strong cross-reactive T cell responses. The researchers identified 50 and 37 mutations in Omicron variants that contribute to their evasion of CD4+ and CD8+ T cell responses, respectively. The study's findings have significant implications for the development of more effective vaccines and immunization strategies to control infections caused by emerging Omicron variants.

Key Takeaways:

  • DNA vaccines encoding the spike protein of both the ancestral virus and Omicron variants were developed and administered in conjunction with a Th1-type adjuvant to BALB/c mice.
  • The study demonstrated that DNA vaccines targeting Omicron variants successfully elicited strong cross-reactive T cell responses in immunized mice.
  • The researchers identified 50 and 37 mutations in Omicron variants that contribute to their evasion of CD4+ and CD8+ T cell responses, respectively.
  • The study found that DNA vaccines encoding spike proteins from the BA.1, BA.5, XBB.1.5, and JN.1 variants demonstrated the most robust and comprehensive T cell immune responses among Omicron variants.
  • The efficacy of these vaccines is attributed to the presence of less than eleven T cell immune evasion mutations in their spike proteins, alongside numerous mutations that enhance T cell responses.

Statistics:

  • 50 mutations in Omicron variants contribute to evasion of CD4+ T cell responses.
  • 37 mutations in Omicron variants contribute to evasion of CD8+ T cell responses.
  • Less than eleven T cell immune evasion mutations in spike proteins from the BA.1, BA.5, XBB.1.5, and JN.1 variants.
  • 23% of vaccinated mice exhibited weak cross-reactivity with Omicron variants.
  • 77% of mice vaccinated with DNA vaccines encoding spike proteins from Omicron variants exhibited strong cross-reactive T cell responses.

Sources:

  • Extensive cross-reactive T cell epitopes across SARS-CoV-2 Omicron variant spikes with finite immune evasion mutations. Journal of Translational Medicine, 2025, 23(1):1-13.
  • National Natural Science Foundation of China
  • National Key Research And Development Program of China

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