Discovery and Significance of Thymosin—January 31, 2000

Discovery and Significance of Thymosin—January 31, 2000

The thymus is located in the upper part of the thoracic cavity, at the base of the sternum, and is a large lymphatic gland composed of two connected lobes. In childhood, the thymus is well-developed, but it gradually atrophies in adulthood, with its lymphatic tissue being obscured by surrounding fat tissue. Previously, people believed that the thymus no longer played a major role in adulthood. However, in 1961, experiments were conducted on mice that had their thymuses removed, revealing that these mice had fewer lymphocytes and gradually lost their immune functions, including both cellular and humoral immunity. Several months after surgery, the mice died of systemic infections. Additionally, it was found that when mature animals had their thymus removed, their lymphocyte counts also declined, leading to a decrease in immune function. These experiments demonstrated that the thymus is not only an important immune organ in young animals, but even in adult animals, although its tissue atrophies, it still retains some function and remains an important immune organ. In 1965, GoldsTein extracted various peptide substances from animal thymus tissue, which exhibited remarkable immune activity. Experiments proved that these active substances significantly promoted both T cells and B cells, as well as interleukin-2, colony-stimulating factors, and interferon-α. Furthermore, it was discovered that these substances also significantly promoted natural killer cells (NK) and activated killer cells (LAK). In the 1970s, China successfully produced thymosin injection; in the 1990s, China successfully developed oral capsules. The dosage of the latter is three times that of the injection, yet the efficacy is the same. Thymosin injection: 3mg, intramuscular injection, once daily; thymosin enteric-coated capsules: 16mg, oral administration, three times daily.