2'3'-cGAMP (Sodium Salt): Benchmark STING Agonist for Innate Immunity Research

Executive Summary: 2'3'-cGAMP (sodium salt) is an endogenous cyclic dinucleotide produced by cGAS in response to cytosolic double-stranded DNA, acting as a high-affinity agonist for STING (Kd = 3.79 nM), resulting in robust type I interferon (IFN-β) induction (APExBIO). The compound is highly water-soluble (≥7.56 mg/mL) and chemically stable when stored at -20°C. STING activation by 2'3'-cGAMP is directly linked to metabolic and immune modulation, including D2HG production in macrophages (Wang et al., 2025). This reagent is a gold-standard tool for dissecting cGAS-STING signaling in cancer, antiviral, and immunometabolic research. It provides a reproducible benchmark for screening STING-targeted compounds and evaluating innate immune responses.

Biological Rationale

2'3'-cGAMP is a cyclic dinucleotide messenger endogenously synthesized by mammalian cGAS upon recognition of cytosolic double-stranded DNA (dsDNA) (APExBIO). It bridges innate DNA sensing to immune activation by binding and activating STING on the endoplasmic reticulum membrane (see also: CRISPR-CasX article; this article extends previous coverage by including metabolic and storage parameters). The cGAS-STING pathway is central to host defense against viral and bacterial infections, linking nucleic acid sensing to type I interferon (IFN-I) production. Aberrant activation or dysregulation of this axis is implicated in autoimmunity, cancer, and chronic inflammation (Wang et al., 2025). 2'3'-cGAMP (sodium salt) provides a standardized, cell-permeable agonist for probing this pathway in cellular and animal models.

Mechanism of Action of 2'3'-cGAMP (sodium salt)

Upon detection of cytosolic dsDNA, cGAS catalyzes the synthesis of 2'3'-cGAMP from ATP and GTP in a magnesium-dependent reaction (APExBIO). 2'3'-cGAMP then binds to the STING protein with a dissociation constant (Kd) of 3.79 nM, triggering a conformational change in STING (compare: IFG-1 article, which details signaling benchmarks; this article adds chemical and storage data). Activated STING recruits and activates TANK-binding kinase 1 (TBK1), which phosphorylates interferon regulatory factor 3 (IRF3). Phosphorylated IRF3 translocates to the nucleus, initiating transcription of type I interferon genes, notably IFN-β. This signaling cascade is essential for antiviral defense, antitumor immunity, and modulation of innate immune responses (Wang et al., 2025).

Evidence & Benchmarks

• 2'3'-cGAMP (sodium salt) binds human STING with a Kd of 3.79 nM, representing the highest known affinity among cyclic dinucleotides (APExBIO).
• STING activation by 2'3'-cGAMP induces robust IFN-β expression in both murine and human cells (Wang et al., 2025).
• 2'3'-cGAMP stimulation increases D-2-hydroxyglutarate (D2HG) production in macrophages, linking STING signaling to immunometabolic changes (Wang et al., 2025, Fig. S4).
• The compound is highly soluble in water (≥7.56 mg/mL), but insoluble in ethanol and DMSO (manufacturer spec: APExBIO).
• Stable storage is achieved at -20°C, preserving bioactivity for long-term experimental use (APExBIO).
• In vivo, 2'3'-cGAMP administration normalizes tumor vasculature via the endothelial STING-JAK1 axis (see also: Carmofur.com article; this article updates with metabolic benchmarks).

Applications, Limits & Misconceptions

2'3'-cGAMP (sodium salt) is a gold-standard reagent for:

• Dissecting cGAS-STING pathway signaling in immunology and inflammation research.
• Screening and benchmarking STING-targeted small molecules and biologics.
• Modeling type I interferon induction in antiviral and cancer immunotherapy contexts.
• Studying immunometabolic crosstalk, including D2HG elevation after STING activation (Wang et al., 2025).
• Validating biosensors and metabolic readouts in engineered cell lines (Wang et al., 2025).

Its benchmark use is described in oncology, antiviral, and metabolic biosensor development (related article provides protocol context; this article details chemical and storage facts).

Common Pitfalls or Misconceptions

• 2'3'-cGAMP (sodium salt) is not cell-permeable in all cell types; transfection or delivery reagents may be required for some primary or suspension cells.
• This reagent is not a direct antiviral or anticancer drug; it is a tool compound for pathway dissection and screening.
• It does not activate non-STING pathways and should not be used to infer cGAS-independent effects.
• Solubility is limited to water; it is insoluble in ethanol and DMSO, so incompatible solvents will result in precipitation or loss of activity.
• Prolonged storage above -20°C may lead to degradation and reduced efficacy.

Workflow Integration & Parameters

The sodium salt form (B8362) is provided as a solid by APExBIO. Reconstitute in water to achieve concentrations ≥7.56 mg/mL. Store aliquots at -20°C for maximal stability (see product page). For cellular assays, deliver via direct addition, electroporation, or transfection, depending on cell type. For in vivo studies, dilute in sterile PBS for injection. Use as a benchmark for STING activation in reporter assays, cytokine ELISAs, and metabolic profiling. The molecular weight is 718.37 g/mol; the empirical formula is C20H22N10Na2O13P2. For reference on cGAS-STING pathway engineering and translational applications, see 23-cgamp.com; this article updates with D2HG metabolic context and validated storage/solubility claims.

Conclusion & Outlook

2'3'-cGAMP (sodium salt) is the reference STING agonist for dissecting innate immune and metabolic pathways. Its quantitative, reproducible activation of the STING pathway underpins its role in immunology, oncology, and antiviral research. Its robust chemical properties and well-characterized mechanism make it ideal for standardizing assays and validating new STING-targeted compounds. Ongoing research continues to reveal its impact on immunometabolism and tumor microenvironment modulation (Wang et al., 2025). For more details and ordering, see the 2'3'-cGAMP (sodium salt) product page.