Thymosin α1

Thymosin α₁ is a peptide fragment derived from prothymosin alpha, a protein that in humans is encoded by the PTMA gene.

It was the first of the peptides from Thymosin Fraction 5 to be completely sequenced and synthesized. Unlike β thymosins, to which it is genetically and chemically unrelated, thymosin α₁ is produced as a 28-amino acid fragment, from a longer, 113-amino acid precursor, prothymosin α.

Function

Thymosin α₁ is an agonist for toll-like receptor 2 and toll-like receptor 9 on both myeloid and dendritic antigen-presenting cells, thereby stimulating the adaptive immune response.

Thymosin α₁ is believed to be a major component of Thymosin Fraction 5 responsible for the activity of that preparation in restoring immune function in animals lacking thymus glands. It has been found to enhance cell-mediated immunity in humans as well as experimental animals.

Therapeutic application

As of 2009 Thymosin α₁ is approved in 35 under-developed or developing countries for the treatment of Hepatitis B and C, and it is also used to boost the immune response in the treatment of other diseases.

Thymosin α₁ is usually administered by subcutaneous injection.

Clinical studies

Clinical trials suggest thymosin α₁ may be useful in cystic fibrosis, septic shock, acute respiratory distress syndrome, peritonitis, acute cytomegalovirus infection, TB, severe acute respiratory syndrome, and lung infections in critically ill patients., and for chronic hepatitis B.

For hospitalized COVID-19 patients, thymosin α₁ has not reduced mortality or length of hospitalization.

It has been studied for possible use in treating cancer (e.g. with chemotherapy).

See also

• Thymosins