Thymosin Alpha-1

Thymosin Alpha-1 peptide, also known as Thymosin Alpha, TA1, or Tα1, is a protein molecule fragment that has been widely studied for its potential implications with the immune system. Researchers have hypothesized that it contributes to T-cell production to mitigate and alleviate infection and bacterial spread.(1)

Thymosin Alpha-1 is a natural polypeptide that researchers consider potentially restores and enhances immune functions.(2) Thymosin Alpha-1 is considered to be one of the polypeptides found in Thymosin Fraction 5, which is a crude extract of the thymus gland.(3)

Since its discovery, a synthetically developed form of Thymosin Alpha-1 has also been studied; researchers refer to the peptide as Thymalfasin.(2) Thymalfasin is composed of 28 amino acids, similar to natural Tα1, and is derived from a longer polypeptide precursor composed of 113 amino acids, known as Prothymosin Alpha.(3)

The primary goal of early research on Thymosin Alpha-1(4) was to understand and examine the peptide's immunomodulatory potential. Studies have suggested that the peptide may increase the concentration of major histocompatibility complex (MHC) class I and cytokine production, which can possibly lead to increased immune responses. The peptide may also improve natural killer cell activity and foster phenotypic marker expression in T cells, suggesting a multifaceted role in immune response modulation. Researchers postulated that the peptide may also increase the expression of high-affinity interleukin-2 receptors. This could potentially lead to more vigorous activation and proliferation of T lymphocytes.

Researchers speculate that Thymosin Alpha-1 may stimulate potential targeted action on helper T cells and cytotoxic T cell populations.(3) Tα1 can possibly induce T cell differentiation (thymocytes) and terminal differentiation of blood lymphocytes. Scientists postulate that it may elevate natural killer cell production and potentially stimulate cytokine-mediated inflammation.(2)(3) Additionally, the peptide has been studied for its potential to improve macrophage efficiency and functions as a modulator of alpha thrombin activity.(3)

Specifications

• Molecular Formula: C129H215N33O55
• Molecular Weight: 3108.31 g/mol
• Other Known Titles: TA1, Tα1, Thymalfasin

In a clinical study,(5) 11 test subjects with different immune system dysfunctions were evaluated to determine the levels of their natural killer (NK) cells and lymphokine-activated killer (LAK) cells present in their system. It was observed that immunodeficient subjects demonstrated a mean LAK cell activity of approximately 65% compared to control subjects. Upon presenting Thymosin Alpha-1 to test subjects, researchers observed an apparent increase in cytotoxic activity and NK cell activity.

A Phase II clinical trial(6) involved critically ill subjects with sepsis. The objective was to evaluate the efficacy and safety of Thymosin Alpha-1 in severe sepsis. The study was randomized into two groups: a control group with a placebo and an experimental group with 1.6 mg of Thymosin Alpha-1 presented subcutaneously twice daily for 5 days. 361 subjects were included in the research. The primary outcome was death, recorded up to 28 days after initiation. Study results indicated a slight decrease in mortality within the Thymosin Alpha-1 group by 26% compared to the control group with a 35% mortality rate. The difference indicated that Thymosin Alpha-1 could be beneficial for severe sepsis, but was not statistically significant.

Studies suggest that Thymosin Alpha-1 may impact inflammatory mediators by affecting Toll-like receptors (TLRs). TLRs are typically associated with innate and adaptive immunity; therefore, TLR dysregulation can lead to autoimmune and inflammatory diseases. Researchers suggest that Thymosin Alpha-1 could affect TLR signaling, potentially improving the adaptive immune response and possibly mitigating inflammation and allergic immune responses. This implies that Thymosin Alpha-1 may influence dendritic cell activity, which is considered vital for T cell activation, thus modulating the immune system.(3)

Initial Phase II clinical studies of Thymosin Alpha-1 were conducted in conjunction with dacarbazine (DTIC) chemotherapy and interferon-alpha (IFN-α) in test subjects with metastatic melanoma. Researchers suggested that combination therapy could lead to potential improvement in overall survival rates and progression-free survival without adding toxicity. However, more recent studies(8) used Thymosin Alpha-1 in combination with IFN-α and DTIC in 488 test subjects with melanoma. Subjects were randomized into combination therapy groups. The study outcome indicated that the addition of Thymosin Alpha-1 did not appear to improve the overall survival rate (9.4 vs. 6.6 months) nor progression-free survival (2.9 vs. 2.2 months).

Researchers also studied(9) the potential of Thymosin Alpha-1 in advanced hepatocellular carcinoma (HCC). Treatment-naive test subjects were enrolled over a year. The primary study outcome was survival, and secondary outcomes included time to progression and disease stability. Results indicated that the median survival rate was 4.8 months for patients with Thymosin Alpha-1 and 4.5 months for control subjects. The 12-month survival rate was 19% for the Thymosin Alpha-1 group vs. 12% for the control group. Overall, researchers concluded that Thymosin Alpha-1 did not induce any statistically significant improvement in overall survival in liver cancer.

Research(2) indicates that Thymosin Alpha-1 may act as an immune adjuvant, potentially improving response to vaccines, particularly in immunocompromised individuals who often do not generate sufficient protective antibodies. Thymosin Alpha-1 is believed to boost antibody production and specific T-cell activation, thus potentially improving vaccine efficacy against various diseases.