NexaVant™ VacciGrade™ - TLR3 & dsRNA-based Vaccine Adjuvant

TLR3 agonist - NexaVant™ (NVT) | Homogeneous and sterile vaccine adjuvant

NexaVant™​ VacciGrade™ is a double-stranded (ds) RNA-based TLR3 agonist and potent vaccine adjuvant, provided in a high-quality pre-clinical grade.

NexaVant™ (NVT) is a synthetic dsRNA of 424 bp chosen from the Chinese sacbrood virus (CSBV) genome. It displays high purity, molecular homogeneity, measurable pharmacokinetics, and non-toxicity in various animals, therefore overcoming various obstacles of currently available dsRNA-based adjuvants (e.g. Poly(I:C)) [1]. It is a potent TLR3 agonist verified using HEK-Blue™ hTLR3 cells (see figures) [1]. It also upregulates specific interferon-stimulated genes (ISGs) including RIG-I, MDA-5, and TLR3[1].

In vivo experiments in mice demonstrated NVT's ability to attract immune cells, activate dendritic cells, and induce strong Th1-type immune responses, such as IFN-γ+ CD4+ and IFN-γ+ CD8+ T cells, surpassing conventional adjuvants like Alum [1]. Moreover, NVT is a promising adjuvant for T cell vaccines, showing enhanced protection against influenza or Mycobacterium tuberculosis infections when used intranasally, promoting lung-resident memory CD4+ T cells that provide broad and long-term immunity against heterosubtypic strains [2-3].

InvivoGen also offers NexaVant™ in a standard grade for in vitro experiments.

Production of NVT

A nucleotide segment (1701-2112; 412 nucleotides) from the CSBV genome, which does not match any human DNA sequence,  was cloned into a vector. After in vitro transcription using T7 RNA polymerase technology, the remaining DNAs and non-specific ssRNAs were removed with the treatment of DNase I and RNase T1 to generate a dsRNA structure having UAUAG-3′ at both ends. Subsequently, the final product was purified by reverse-phase HPLC [1]. NexaVant™ is available at cGMP grade from the NA Vaccine Institute.

Key features

• Potent TLR3 agonist and vaccine adjuvant
• Strong Th1 responses inducer
• Highly pure (≥ 95%) and stable
• Ready-to-use liquid
• Batch-to-batch consistency
• Each lot is functionally tested

1. Ko KH, et al., 2023. A novel defined TLR3 agonist as an effective vaccine adjuvant. Front Immunol. ;14:1075291.
2. Ko KH, et al. 2024. A vaccine platform targeting lung-resident memory CD4+ T-cells provides protection against heterosubtypic influenza infections in mice and ferrets. Nat Commun.15(1):10368.
3. Ko KH, et al. 2025. A vaccine targeting lung resident-memory CD4(+) T cell phenotype protects against Mycobacterium tuberculosis in mice. NPJ Vaccines. 10(1):161.