TNF alpha human
Description
Biological Functions
TNF-α regulates diverse processes through concentration-dependent and cell-type-specific mechanisms:
Low concentrations (pg/mL) promote cell proliferation and survival, while high concentrations (ng/mL) trigger apoptosis .
Mechanisms of Action
TNF-α signaling bifurcates through TNFR1 and TNFR2:
| Receptor | Expression | Pathway | Outcome |
|---|---|---|---|
| TNFR1 | Ubiquitous | TRADD → NF-κB/MAPK/apoptosis | Pro-inflammatory response, cell death |
| TNFR2 | Immune/endothelial | TRAF2 → PI3K/Akt | Cell survival, tissue regeneration |
TNFR1 activation dominates cytotoxic effects, whereas TNFR2 supports immune cell proliferation and regenerative processes .
Clinical Implications
Dysregulated TNF-α is implicated in multiple pathologies:
| Disease | Role of TNF-α | Therapeutic Approach |
|---|---|---|
| Autoimmune Disorders | Drives inflammation in RA, IBD, and psoriasis | TNF inhibitors (e.g., infliximab) |
| Cancer | Promotes tumor angiogenesis/metastasis; paradoxically induces cytotoxicity | Isolated limb perfusion with TNF-α |
| Neurodegeneration | Exacerbates neural apoptosis in ischemia | TNF-α preconditioning via NF-κB |
Clinical trials of systemic recombinant TNF-α (rhTNF-α) in the 1980s–1990s faced toxicity challenges, but localized delivery shows promise in sarcoma and melanoma .
Key Research Findings
Recent studies highlight TNF-α's dual roles:
For example, the −308 polymorphism in the TNF-α promoter correlates with severe malaria outcomes due to heightened cytokine production .
Unanswered Research Questions
Product Specs
Tumor necrosis factor (TNF) is a cytokine, which is a type of signaling molecule that helps regulate the immune system. TNF is involved in a process known as the acute phase reaction, which is the body's initial response to infection or injury. TNF is primarily produced by a type of white blood cell called a macrophage.
TNF has a wide range of effects on cells, including triggering cell death (apoptosis), stimulating cell growth and division (proliferation), and promoting inflammation. It is also involved in other processes such as the formation of new blood vessels (angiogenesis), the breakdown of fats (lipid metabolism), and blood clotting (coagulation). TNF's main function is to control the activity of immune cells.
When TNF production is disrupted or excessive, it can contribute to the development of various diseases, including autoimmune disorders (where the immune system attacks the body's own tissues), insulin resistance (a condition that can lead to type 2 diabetes), and cancer.
The purification of TNF-alpha is achieved through a series of standard chromatographic separation techniques.
Human TNF-alpha was lyophilized from a concentrated solution of 1mg/ml. This solution contained 20mM PB (phosphate buffer) at a pH of 7.2 and 100mM NaCl (sodium chloride).
Lyophilized Tumor Necrosis Factor-alpha remains stable at room temperature for up to 3 weeks; however, it is recommended to store it in a dry environment below -18 degrees Celsius. After reconstitution, TNF-alpha should be stored at 4 degrees Celsius for a period of 2 to 7 days. For longer-term storage, it is advisable to freeze it below -18 degrees Celsius.
To ensure optimal stability during long-term storage, it is recommended to add a carrier protein such as HSA (human serum albumin) or BSA (bovine serum albumin) at a concentration of 0.1%.
Repeated freezing and thawing of the protein should be avoided.
(a) Analysis by RP-HPLC (Reverse-Phase High-Performance Liquid Chromatography).
(b) Analysis by SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis).
Product Science Overview
TNF-α exists in two forms: a type II transmembrane protein and a mature soluble protein. The transmembrane protein is proteolytically cleaved to yield a soluble protein, which subsequently forms a non-covalently linked homotrimer in solution . Each subunit of this homotrimer has a relative molecular mass of approximately 17,350 Daltons .
Recombinant human TNF-α is produced in Chinese hamster ovary (CHO) cells that have been transfected with the full-length sequence for the human TNF-α gene . These transfected cells produce and secrete biologically active TNF-α, which is then purified by affinity chromatography . The recombinant protein is typically lyophilized from a filtered solution in PBS (pH 7.4) with human serum albumin (HSA) as a carrier protein .
TNF-α is a pleiotropic molecule that plays a central role in inflammation, immune system development, apoptosis, and lipid metabolism . It promotes angiogenesis, bone resorption, and thrombotic processes . TNF-α can drive both tumor elimination and promotion in cancer patients, depending on the dose and cancer type . Overexpression of TNF-α in engineered tumor cells has been shown to block their engraftment and growth, creating a tumor-suppressive microenvironment .
Recombinant human TNF-α is used in various research applications, including the induction of NF-κB and AP-1 pathways in HEK-Blue™ TNF-α cells . It has also been used as a ‘pre-activator’ of human mesenchymal stromal cells (MSCs) to stimulate the production of pro-apoptotic ligand TRAIL, reducing the growth of experimental metastases .
