IL12 Human, Sf9
Description
Molecular Composition and Production
IL-12 Human, Sf9 refers to recombinant human IL-12 produced in Sf9 cells via baculovirus expression. The protein is a glycosylated heterodimer comprising:
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p35 subunit: 197 amino acids (22–24 kDa theoretical mass, ~25.5 kDa observed due to glycosylation)
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p40 subunit: 306 amino acids (34–37 kDa theoretical mass, ~40–45 kDa observed)
The subunits are linked via disulfide bonds, forming a 60–70 kDa bioactive complex . Sf9 cells enable high-yield expression with proper post-translational modifications, critical for receptor binding and activity .
Table 1: Key Physicochemical Parameters
Functional Activity and Mechanisms
IL-12 Human, Sf9 demonstrates enhanced bioactivity compared to mammalian-expressed variants:
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IFN-γ Induction: 5–10× more potent in activating T cells and NK cells .
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Th1 Differentiation: Synergizes with IL-2 and IL-18 to drive STAT4 phosphorylation and IFN-γ production .
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Cytotoxic Activity: Upregulates perforin and granzyme B in lymphocytes .
Key Findings from Directed Evolution Studies:
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EvIL-12 (evolved IL-12) showed 128× higher activity than wild-type IL-12 in IFN-γ induction due to improved receptor binding and stability .
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Mutations at the p40/IL-12Rβ1 interface (e.g., Pro39Ala, Asp40Ala) reduced STAT4 signaling, highlighting critical interaction sites .
Table 2: Receptor Interaction Residues
| Subunit | Critical Residues | Functional Role |
|---|---|---|
| p35 | Tyr62, Tyr189, Lys192 | High-affinity binding to IL-12Rβ2 |
| p40 | Glu81, Phe82, Pro39, Asp40 | Stabilizes IL-12Rβ1 interaction |
Cryo-EM studies (PDB: 8XRP) revealed conformational plasticity in the IL-12 heterodimer, influencing signaling efficiency .
A. Cancer Immunotherapy
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Enhances CD8+ T-cell cytotoxicity and tumor regression in preclinical models .
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Clinical trials use GMP-grade IL-12 (e.g., 219-GMP) with ED₅₀ = 0.01–0.05 ng/mL .
B. Autoimmune Disease Modulation
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Targeting the shared p40 subunit (with IL-23) via antibodies (e.g., ustekinumab) treats Crohn’s disease and psoriasis .
C. Infectious Disease Models
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Restores IFN-γ-dependent immunity in intracellular pathogen infections (e.g., Mycobacterium tuberculosis) .
Comparative Advantages of Sf9-Produced IL-12
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Cost-Effective Scalability: Higher yields than mammalian systems (e.g., HEK293) .
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Authentic Glycosylation: Maintains receptor affinity and in vivo stability .
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Low Endotoxin: Suitable for preclinical and clinical formulations .
Challenges and Future Directions
Product Specs
23-219aa (IL12A) / 23-328aa (IL12B), Interleukin 12 (subunit beta/alpha), IL12 His, NKSF1, NKSF, CTL maturation factor (TCMF), Cytotoxic lymphocyte maturation factor (CLMF), TSF, Edodekin-alpha, IL-12.
Baculovirus.
IL-12 is a heterodimer of IL-12A and IL-12B linked through a disulfide-bond:
>IL-12 ARNLPVATP DPGMFPCLHH SQNLLRAVSN MLQKARQTLE FYPCTSEEID HEDITKDKTS TVEACLPLEL TKNESCLNSR ETSFITNGSC LASRKTSFMM ALCLSSIYED LKMYQVEFKT MNAKLLMDPK RQIFLDQNML AVIDELMQAL NFNSETVPQK SSLEEPDFYK TKIKLCILLH AFRIRAVTID RVMSYLNAS.
>IL-12B
IWELKKDV YVVELDWYPD APGEMVVLTC DTPEEDGITW TLDQSSEVLG SGKTLTIQVK EFGDAGQYTC HKGGEVLSHS LLLLHKKEDG IWSTDILKDQ KEPKNKTFLR CEAKNYSGRF TCWWLTTIST DLTFSVKSSR GSSDPQGVTC GAATLSAERV RGDNKEYEYS VECQEDSACP AAEESLPIEV MVDAVHKLKY ENYTSSFFIR DIIKPDPPKN LQLKPLKNSR QVEVSWEYPD TWSTPHSYFS LTFCVQVQGK SKREKKDRVF TDKTSATVIC RKNASISVRA QDRYYSSSWS EWASVPCS.
Product Science Overview
IL-12 is a heterodimeric cytokine composed of two subunits: IL-12A (p35) and IL-12B (p40). The recombinant human IL-12 produced in Sf9 cells is a glycosylated heterodimer containing 503 amino acids, with a molecular mass of approximately 60 kDa . The two subunits are linked through a disulfide bond, which is essential for its biological activity .
IL-12 is a potent regulator of cell-mediated immune responses. It induces the production of interferon-gamma (IFN-γ) by natural killer (NK) cells and T cells, enhancing their cytotoxic activity . IL-12 also promotes the differentiation of naive T cells into Th1 cells, which are essential for the immune response against intracellular pathogens and tumors .
The recombinant form of IL-12 has been explored for its potential in cancer immunotherapy due to its ability to activate NK cells and cytotoxic T lymphocytes . Clinical trials have investigated the use of IL-12 in treating various cancers, HIV, and hepatitis virus infections . However, the therapeutic application of IL-12 has been limited by its toxicity, particularly the risk of cytokine release syndrome (CRS) .
The recombinant human IL-12 produced in Sf9 cells is purified using proprietary chromatographic techniques to ensure high purity (>97%) . The lyophilized form of IL-12 is stable at room temperature for up to three weeks but should be stored desiccated below -18°C for long-term storage . Upon reconstitution, it should be stored at 4°C for short-term use and below -18°C for future use .
