Thymosin Alpha-1

Thymosin Alpha-1 (Tα1) is a 28 amino acid peptide (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-OH) originally isolated from bovine thymosin fraction 5 by Goldstein et al. in 1977. It is the most clinically advanced thymic peptide — marketed as Zadaxin (SciClone Pharmaceuticals) and approved in multiple countries for hepatitis B, hepatitis C, and immunodeficiency conditions, providing extensive published clinical pharmacology data for research context.

Thymosin Alpha-1 activates Toll-like receptors (TLR2, TLR4, TLR9) on dendritic cells and macrophages, driving innate immune activation. Published research has characterised TLR-mediated NFkB and IRF3 signalling downstream of Tα1, producing type I interferon (IFN-alpha, IFN-beta) and pro-inflammatory cytokine production. This TLR agonist mechanism is distinct from other immunostimulatory peptides and places Tα1 firmly within the pattern recognition receptor pharmacology research space.

T lymphocyte biology research with Thymosin Alpha-1 has examined thymic T cell maturation (CD4/CD8 single positive selection), peripheral T cell activation thresholds, regulatory T cell (Treg) modulation, and Th1/Th2 balance. Published data has suggested Tα1 promotes Th1-dominant immune responses through IFN-gamma production enhancement, with potential anti-Th2 effects relevant to allergy and asthma research models.

Dendritic cell maturation is a second major research theme: Tα1 treatment of immature dendritic cells drives upregulation of MHC II, CD80, CD86, and CD40 maturation markers (measured by flow cytometry), enhanced antigen presentation capacity, and increased IL-12 production — promoting adaptive immune priming.

NK cell activity research has examined Tα1 effects on natural killer cell cytotoxicity against tumour cell targets (51Cr release assay, LAMP-1 degranulation) and NK cell IFN-gamma production, relevant to innate anti-tumour immune research.

MW: 3108.4 g/mol. CAS: 62304-98-7. Molecular formula: C129H215N33O55. Reconstitute in bacteriostatic water at 1mg/mL. Store lyophilised at -20°C. For laboratory and analytical research purposes only.

Thymosin Alpha-1 quality assessment and activity confirmation: before research experiments, confirm Thymosin Alpha-1 biological activity using a validated functional assay. The most commonly used confirmatory assay is TLR9-mediated dendritic cell activation: incubate human monocyte-derived dendritic cells (generated from PBMCs by 7-day GM-CSF/IL-4 culture) with Thymosin Alpha-1 (1-100nM) for 24 hours, then measure IL-12p70 production (ELISA) in conditioned medium. Active Thymosin Alpha-1 should produce a statistically significant increase in IL-12p70 at concentrations above 10nM compared to vehicle control.

For T cell biology research comparing Thymosin Alpha-1 with Thymalin and Vilon: isolate CD4+ T cells by negative selection from human PBMCs. Rest overnight in serum-free medium, then stimulate with anti-CD3 antibody (1µg/mL plate-bound) with or without 72-hour pre-treatment with Thymosin Alpha-1 (1-100nM), Thymalin (1-100nM), or Vilon (1-100nM). Measure: proliferation by CFSE dilution; IL-2 secretion (ELISA, 24 hours); IFN-gamma secretion (ELISA, 72 hours); Treg induction (FoxP3+ CD25+ CD4+ by intracellular flow cytometry). This parallel comparison directly characterises the potency and immune subset specificity of each thymic bioregulator at the level of primary human T cell biology. MW: 3108.4 g/mol. CAS: 62304-98-7. Reconstitute in bacteriostatic water at 1mg/mL. Store lyophilised at -20°C. For laboratory and analytical research purposes only.

Thymosin Alpha-1 clinical pharmacology reference data: the Zadaxin clinical dataset provides important research context. Subcutaneous administration at 1.6mg twice weekly produces peak plasma concentrations of approximately 1-2ng/mL within 2 hours, with a plasma half-life of approximately 2 hours. At these plasma concentrations, Thymosin Alpha-1 produces measurable immunological effects — establishing the therapeutic concentration range for contextualising in vitro research concentrations. Research at 0.1-10nM brackets the estimated receptor-occupancy range from published clinical exposures, allowing direct translational comparison between in vitro mechanistic data and clinical observations. For TLR pharmacology research: confirm TLR dependence using TLR2-knockout, TLR4-knockout, and TLR9-knockout dendritic cells (or cells with siRNA knockdown of individual TLR subtypes) versus wild-type cells in parallel Thymosin Alpha-1 stimulation experiments. The relative IL-12 response across TLR-knockout versus wild-type cells identifies which TLR subtype drives the published immunostimulatory activity — critical mechanistic data for understanding the receptor basis of Thymosin Alpha-1's clinical immune effects. MW: 3108.4 g/mol. CAS: 62304-98-7. Reconstitute in bacteriostatic water at 1mg/mL. Store lyophilised at -20°C. For laboratory and analytical research purposes only.