The thymus is the site of T-cell development and maturation. It is also a source of numerous immune-modulating factors. Thymic hormones that are known to induce phenotypic changes in thymocytes in vitro and/or alter T cell function in vivo are thymopoetin, thymic humoral factor, thymulins, and thymosin alpha 1 (ThyA). Thymosin A1 is an immunomodulatory polypeptide produced endogenously by the thymus gland. It has a wide range of immuno-enhancing properties including differentiation and maturation of T-cell progenitor cells, activation of dendritic and natural killer cells, and stimulation of cytokine release.
Thymosin A1 also acts as an anti-inflammatory and hepatoprotective agent. It decreases oxidative damage to hepatocytes by enhancing the activity of catalase, superoxide dismutase, and glutathione peroxidase. It also prevents hepatitis C virus oxidative stress-induced cellular death.
In addition, thymosin A1 is a tumor-targeting peptide that binds to RGDR on cancerous cells, thus causing integrin to be activated and leading to the infiltration of T lymphocytes into tumors. It is effective in several human cancers including hepatocellular carcinoma, lung cancer, and melanomas.
People who are undergoing chemotherapy or radiation are good candidates for thymosin A1 therapy, as it is capable of reducing toxicity and preventing chemo- or radiation-induced lymphopenia. However, it is important to note that thymosin A1 has been administered to people of all ages from children to adults over 100 years old. While health conditions and age can impact how well this peptide works, everyone can benefit from a stronger immune system.