Thymosin Alpha-1

Thymosin Alpha-1 (Tα1; also known as Thymalfasin) is a synthetic 28-amino acid acetylated polypeptide derived from the naturally occurring thymic peptide prothymosin alpha. It was originally isolated from thymosin fraction 5, a crude extract of the thymus gland. The compound is classified as a biological response modifier (BRM) with potent immunomodulatory properties. Thymosin Alpha-1 is widely studied for its ability to enhance both innate and adaptive immune responses and has been approved in more than 35 countries for the treatment of chronic hepatitis B and C infections.

Thymosin Alpha-1 exerts its pleiotropic immunomodulatory effects through multiple interconnected mechanisms. It acts as an agonist of Toll-like receptors (TLRs), particularly TLR-2 and TLR-9, on myeloid and plasmacytoid dendritic cells. This activation triggers downstream signaling cascades, predominantly the MyD88-dependent pathway, leading to the production of immune-related cytokines. Tα1 enhances the function of various immune cells, including T cells (promoting T-cell differentiation and maturation), B cells, natural killer (NK) cells, macrophages, and dendritic cells. It also promotes Th1 immune responses and modulates cytokine and chemokine production. Additionally, Tα1 interacts with galectin-1 (Gal-1) at the molecular level, affecting its carbohydrate-binding activity and modifying its biological functions.

• Viral Infections: Investigated for the treatment of chronic hepatitis B and C, often in combination with interferon therapy. Also studied for influenza, cytomegalovirus, and post-COVID immune reconstitution.
• Cancer Immunotherapy: Employed as an immune enhancer in oncology research, particularly in combination with PD-1 inhibitors, radiotherapy, and chemotherapy. Studies demonstrate Tα1 can protect lymphocytes from radiation-induced lymphocytopenia, enhance T lymphocyte function, and reverse CD8⁺ T-cell exhaustion.
• Immunodeficiency and Immune Reconstitution: Studied for restoring immune balance in immunocompromised states, including DiGeorge syndrome, and for modulating T-cell differentiation in conditions of immune dysregulation.
• Autoimmune and Inflammatory Disorders: Investigated for its role in T-cell tolerance, regulatory immunity, and modulation of neuroinflammatory conditions including stroke, traumatic brain injury, and neurodegeneration.
• Vaccine Research: Explored as a vaccine adjuvant to enhance immune responses.

CAS Number: 62304-98-7
PubChem CID: 16130571
Molecular Formula: C₁₂₉H₂₁₅N₃₃O₅₅
Molecular Weight: 3,108.28 g/mol
Sequence: Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn (ACSAADVDTSSEITTKDLKEKKEVVEEAEN)
Purity: ≥ 99%
Form: Lyophilized powder
Storage: Store at ≤ -20°C in a cool, dry place, protected from light and moisture
Solubility: Soluble in sterile water; prepare working solutions per laboratory protocol