Thy Alpha 1

Thymosin Alpha 1 (Tα1), tambem conhecido(a) como thymalfasin (trade name Zadaxin), is a highly conserved, acidic polypeptide consistindo de 28 aminoacido residues with a peso molecular of 3,108.3 Da e um(a) isoelectric point (pI) of 4.2. [1] [2]

Origin: Tα1 was originalmente isolado(a) de thymosin fraction 5 (TF5) — a crude extract from calf thymus — in 1977 by Dr. Allan L. Goldstein no(a) Albert Einstein College of composto de pesquisa. [2] It is derivado(a) de a larger precursor protein called prothymosin alpha (ProTα) (109–111 aminoacidos) via cleavage pelo(a) lysosomal asparaginyl endopeptidase legumain (δ-secretase). [3]

Structural Features: Linear polypeptide, N-terminally acetylated, no disulfide bonds, no glicosilacao. In aqueous solution, Tα1 is intrinsically disordered; upon binding to membranes or receptors, it adopts an α-helix conformation (residues 14–26). [8]

Regulatory Status:

• International: Approved in 30+ countries (China, Italy, Asia, Latin America, Eastern Europe) for cronico(a) hepatitis B, hepatitis C, and como um(a) vaccine adjuvant/chemotherapy adjunct. [5]
• FDA: Composto Orfao designation for HCC, malignant melanoma, and DiGeorge anomaly. NOT generally registered for marketing. [6]
• FDA Categoria 2: As of 2023/2024, placed no(a) Categoria 2 Substancia Farmaceutica a Granels list, restricting manipulacao pharmacy use. [7]
• WADA: May fall under broader banned peptide categories (note: Thymosin Beta-4 is explicitly prohibited; Tα1 status is context-dependent).

Developer: Originally developed by Alpha 1 Biomedicals Inc.; commercial rights acquired by SciClone Pharmaceuticals, que launched Zadaxin globally. [9]

Pharmacokinetic Highlights:

• Half-Life: ~2 hours (serum)
• Peak Levels: 1–2 hours post-subcutaneo(a) injection
• Urinary Excretion: 31–60% of administered dose
• Route: Subcutaneous (standard clinical route)
• Standard Clinical Dose: 1.6 mg SC (Zadaxin formulation)

1. Parent Molecule — Prothymosin Alpha

Tα1 e o(a) N-terminal fragment (residues 1–28) do(a) larger precursor protein prothymosin alpha (ProTα), an acidic nuclear protein of 109–111 aminoacidos envolveu in chromatin remodeling and proliferacao celular. ProTα is cleaved pelo(a) lysosomal enzyme legumain (δ-secretase) to release the bioactive Tα1 peptide. [3]

Structural Conformation: In aqueous solution, Tα1 is intrinsically unstructured (disordered). Upon interaction with negatively charged membranes (especialmente those exposing phosphatidylserine) or organic solvents, it adopts a structured conformation with an α-helix from residues 14–26 and two double β-turns no(a) N-terminal residues. [8]

2. Alvo Receptor Primarios

Tα1 functions como um(a) pleiotropic modulator by interacting with pattern recognition receptors (PRRs) and specific membrane components:

• TLR9 and TLR2 Agonist: Signals through TLR9 in plasmacytoid dendritic cells (pDCs) and TLR2 in myeloid dendritic cells (mDCs). [4]
• Membrane Interaction: N-terminal inserts into hydrophobic regions of cell membranes, particularmente those exposing phosphatidylserine (PS) (found on apoptotic cells), triggering signal transduction.
• Hyaluronic Acid (HA) Interaction: C-terminal “LKEKK” motif interacts electrostatically with HA, potentially interfering with CD44/RHAMM binding and suppressing tumor progression.

3. Sinalizacao a Jusante Cascades

A. MyD88 → TRAF6 → IKK → NF-κB (Immune Activation):

TLR9/TLR2 estimulacao recruits the adaptor protein MyD88, activating TRAF6 → IKK complex → NF-κB transcricao factor, promoting cytokine expressao genica (IL-2, IFN-γ, IL-12). Often envolve atypical PKC. [4] [10]

B. p38 MAPK / JNK (DC Maturation):

Tα1 induz fosforilacao of p38 MAPK and JNK (c-Jun N-terminal kinase). The p38 MAPK pathway is critico(a) para dendritic cell maturacao and production of Th1-priming cytokines. [11]

C. cAMP / PKC (Anti-Apoptosis in Thymocytes):

In thymocytes, Tα1 antagonizes steroid-induziu apoptose by stimulating cAMP production and activating PKC-dependent pathways.

D. IDO1 Pathway → Immune Tolerance:

Through TLR9 and Type I interferon receptor signaling, Tα1 induz IDO1 in dendritic cells, activating tryptophan catabolism (kynurenines), que promove generation of regulatory T cells (Tregs) — inducing immune tolerance and dampening excessive inflamacao/cytokine storms. [12]

The product supplied here is for uso em pesquisa apenas independentemente de regulatory status of related formulations.

4. Cellular and Tissue-Level Effects

Dendritic Cells:

• Promotes functional maturacao, increasing expression of HLA-DR, CD86, and CD40
• Stimulates IL-12 production → drives Th1 phenotype (antiviral/antitumor) [4]
• Can also promote tolerance via IDO1 pathway [12]

T-Cells:

• Promotes diferenciacao of celulas-tronco into thymocytes
• Increases ativou CD4+ and CD8+ T cell numbers
• Antagonizes glucocorticoid-induziu apoptose in immature thymocytes

Macrophages:

• Activates complement receptor (CR)-mediated phagocytosis (via actin/vinculin recruitment), distinto(a) de Fc receptor mechanisms [13]
• Dose-dependent response at 50–100 ng/mL

Tumor Cells:

• Upregula MHC Class I expression, making tumors mais visible to cytotoxic T cells
• Can directly inhibit proliferacao celular in certain cancer lines

NK Cells:

• Enhances NK cell activity and function [5]

5. Selectivity and Cross-Reactivity

Tα1 acts como um(a) “regulator of regulators” — modulating the sensitivity of TLRs to outro(a) stimuli (e.g., viral antigens) rather do que solely acting como um(a) direto(a) agonist. It is highly conserved across mammalian species (human, bovine, porcine, ovine). [5]

Distinct from Thymosin Beta-4 (TB-500): While Tα1 focuses on adaptive/innate immune modulacao (TLR/T-cell maturacao), TB-500 is primariamente an actin-sequestering protein envolveu in cell motility, cicatrizacao de feridas, and reparo tecidual.

6. Pharmacokinetics

Parameter	Value
Route	Subcutaneous (standard)
Peak Serum Levels	1–2 hours post-SC injection
Half-Life (T½)	~2 hours
Urinary Excretion	31–60% of administered dose
Dose-Response	Proportional Cmax/AUC for 0.8–6.4 mg single / 1.6–16 mg multiplos(as)
Accumulation	No evidence of accumulation with repeated dosing
Albumin Binding	C-terminal residues 11–20 bind HSA (carrier)

🦠 Viral Infections (Hepatitis B & C)

Tα1 is a maioria estabeleceu for cronico(a) Hepatitis B (CHB) and Hepatitis C (CHC). Clinical data demonstra induction of HBeAg seroconversion, ALT normalization, and viral supressao, with synergistic effects quando combined with interferon-alpha or nucleoside analogs. [5]

🎯 Oncology (Solid Tumors)

Research demonstra efficacy in malignant melanoma, hepatocellular carcinoma (HCC), and NSCLC. Tα1 is used como um(a) adjuvant to chemotherapy (e.g., dacarbazine) or immunotherapy (e.g., ipilimumab), reducing tumor growth, increasing survival, and mitigating chemo-induziu toxicity. [14] [15]

🏥 Sepsis

In severe sepse, Tα1 reverses immunosupressao by upregulating HLA-DR expression on monocitos and preventing linfocito apoptose. The ETASS trial (n=361) showed 26% vs 35% mortality (P=0.049). [16]

🦠 COVID-19 / SARS

During the COVID-19 pandemic, Tα1 was used in severe cases para restaurar lymphocytopenia and reverse T-cell exhaustion. A Wuhan retrospective study (n=76) showed observado(a) effects on immune markers em ambientes de pesquisa. [17]

💉 HIV/AIDS

Studied as adjunct to HAART, facilitating immune reconstitution by increasing CD4+ T-cell counts and sjTRECs (markers of thymic output). [18]

💉 Vaccine Adjuvant

Enhances immunogenicity of influenza, H1N1, and HBV vaccines, particularmente in immunocompromised populations (elderly, hemodialysis sujeitos de estudo). In hemodialysis sujeitos de estudo, 89% vs 53% seroconversion with H1N1 vaccine (P<0.01). [19]

🫁 Cystic Fibrosis (CF)

Tα1 has shown potential to correct maturacao/activity of mutated F508del-CFTR protein enquanto simultaneamente reducing lung inflamacao, though reproducibility has been debated. [20]

🍄 Fungal & Bacterial Infections

Activates dendritic cells for Th1 resistance against invasive aspergillosis and aprimora resistance to Pseudomonas in bone marrow transplant settings. [4]

🔬 Autoimmune Diseases

sujeitos de estudo with psoriatic arthritis, rheumatoid arthritis, and SLE exhibit lower serum Tα1 levels. Administration may restore immune homeostasis and regulate inflamacao. [21]

Clinical Trials

Preclinical Animal Data (Selected)

• Lung Cancer (LLC/H460): 0.25 mg/kg SC × 11 days — 40.5% tumor volume inibicao (LLC), 21.9% inibicao (H460). Promoted CD4+/CD8+ T cell infiltration. [22]
• Melanoma (B16F10): Monotherapy reduziu lung metastases by 32% (P<0.05); tumor growth diminuiu 34–46% (P=0.001–0.015). [5]
• Lung Adenoma Prevention: 0.4 mg/kg SC daily — reduziu adenoma multiplicity by ~45% at 2.5 months.
• Leukemia/Carcinoma Combo: Tα1 (200 µg/kg) + IL-2/IFN + cyclophosphamide alcancou complete tumor regression in FLC and 3LL models. [23]
• Sepsis (CLP): Tα1 + dexamethasone alcancou highest survival rate; reversed DC depletion.
• Immunosupressao: 100–1,000× mais ativo(a) do que thymosin fraction 5 in restoring immunity in 5-FU models.
• Aging: Restored antibody and T-cell responses in camundongos idosos (23–24 months) to levels comparable to young animals. [24]
• Arthritis (CIA): 0.25–1 mg/kg reduziu paw volume, weight, and arthritic scores.

Reported Tolerability Profile

Tα1 is consistently relatado(a) as bem tolerado(a) across 2,000+ clinical subjects. [1]

• Common: Local injection site discomfort/redness (most frequent)
• Rare: Fever, fatigue, muscle aches, nausea (usually quando combined with IFN)
• Hepatic: Transient ALT flares in HBV aplicacao em pesquisa (often a sign of experimental effect)
• Serious (rare): Fatal immune hemolytic anemia and engraftment failure in HSCT recipients
• Preclinical: Single doses up to 20 mg/kg and 13-week repeated doses up to 6 mg/kg/day showed no adverse reactions

Contraindications: Hypersensitivity to Tα1; organ transplant recipients (risk of rejection/GVHD via immune estimulacao). [1]