Enantiomer-dependent and modification-free DNA matrix as an adjuvant for subunit vaccines against SARS-CoV-2 or pneumococcal infections

Nat Biomed Eng. 2025 Dec;9(12):2043-2067. doi: 10.1038/s41551-025-01431-7. Epub 2025 Jul 8.

Abstract

The emergence of novel infectious disease has intensified demand for more advanced vaccine development and more potent adjuvants to enhance immunogenicity. Here we introduce a dynamic DNA supramolecular matrix assembled from five unmodified, short DNA single strands, serving as a safe, multifaceted adjuvant platform. This DNA matrix elicits a robust humoral response with minimal adverse effects, generating potent neutralizing antibodies and conferring robust protection against SARS-CoV-2 and Streptococcus pneumoniae infections. Its dynamic colloidal feature prolongs the in vivo retention of both DNA and antigen, facilitating lymphatic-targeted transportation and presentation. This process leads to a robust pro-inflammatory response in both the vaccinated site and draining lymph node, which, in turn, promotes the recruitment and activation of immune cells, leading to a rapid, effective antigen-specific antibody response. The enhanced function of DNA matrix depends on the canonical TLR9-MyD88 signalling axis in dendritic cells. In addition, only right-handed, not left-handed, chirality of the DNA strands forms D-DNA matrix and promotes immune activations. Thus, this DNA matrix functions as an all-in-one adjuvant platform, opening promising avenues for future vaccine design.

MeSH terms

  • Adjuvants, Vaccine* / chemistry
  • Animals
  • COVID-19 Vaccines* / chemistry
  • COVID-19 Vaccines* / immunology
  • COVID-19* / prevention & control
  • DNA, Single-Stranded* / chemistry
  • DNA, Single-Stranded* / immunology
  • Dendritic Cells
  • Humans
  • Lymph Nodes / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / metabolism
  • Pneumococcal Infections / prevention & control
  • Pneumococcal Vaccines* / chemistry
  • Pneumococcal Vaccines* / immunology
  • Signal Transduction
  • Streptococcus pneumoniae / immunology
  • Toll-Like Receptor 9 / genetics
  • Toll-Like Receptor 9 / metabolism
  • Vaccines, Subunit / chemistry
  • Vaccines, Subunit / immunology

Substances

  • Vaccines, Subunit
  • COVID-19 Vaccines
  • Pneumococcal Vaccines
  • Adjuvants, Vaccine
  • Toll-Like Receptor 9
  • Myeloid Differentiation Factor 88
  • DNA, Single-Stranded