Biology:Thymosin α1
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| Formula | C129H215N33O55 |
| Molar mass | 3108.315 g·mol−1 |
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Thymosin α1 is a peptide fragment derived from prothymosin alpha, a protein that in humans is encoded by the PTMA gene.[1]
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 having the sequence Ac-SDAAVDTSSEITTKDLKEKKEVEEEAEN, which is made from cleavage of a longer, 113-amino acid precursor, prothymosin α.[2]
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.[3]
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.[4]
Therapeutic application
Thymosin α1 is approved in some 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.[5][6] The synthetic version of Thymosin α1 is known as Thymalfasin and is sold under the brand name Zadaxin.[7]
Thymosin α1 is usually administered by subcutaneous injection.[3]
Clinical studies
Clinical trials suggest thymosin α1 may be useful in cystic fibrosis, septic shock,[8] acute respiratory distress syndrome, peritonitis, pancreatitis,[9] acute cytomegalovirus infection, TB, severe acute respiratory syndrome, and lung infections in critically ill patients.,[6][10] and for chronic hepatitis B.[11][12][13]
For hospitalized COVID-19 patients, a 2023 review concluded thymosin α1 was not effective in reducing mortality or length of hospitalization.[14] A subsequent 2023 review contradicted this, showing a reduction in mortality but not length of stay.[15]
It has been studied for possible use in treating cancer (e.g. with chemotherapy).[16]
See also
References
- ↑ "The human prothymosin alpha gene family contains several processed pseudogenes lacking deleterious lesions". Genomics 13 (2): 319–31. Jul 1992. doi:10.1016/0888-7543(92)90248-Q. PMID 1612591. https://zenodo.org/record/1258589.
- ↑ Garaci E (September 2007). "Thymosin alpha1: a historical overview". Ann. N. Y. Acad. Sci. 1112: 14–20. doi:10.1196/annals.1415.039. PMID 17567941.
- ↑ 3.0 3.1 "Thymosin alpha 1: A comprehensive review of the literature". World Journal of Virology 9 (5): 67–78. 2020. doi:10.5501/wjv.v9.i5.67. PMID 33362999.
- ↑ "Thymosin activity in patients with cellular immunodeficiency". N. Engl. J. Med. 292 (2): 70–4. January 1975. doi:10.1056/NEJM197501092920204. PMID 1078552.
- ↑ "Thymosin alpha 1: from bench to bedside". Ann. N. Y. Acad. Sci. 1112 (1): 225–34. September 2007. doi:10.1196/annals.1415.044. PMID 17600290. Bibcode: 2007NYASA1112..225G.
- ↑ 6.0 6.1 "From lab to bedside: emerging clinical applications of thymosin alpha 1". Expert Opin Biol Ther 9 (5): 593–608. May 2009. doi:10.1517/14712590902911412. PMID 19392576.
- ↑ "Therapeutic applications of thymosin peptides: A patent landscape 2018-present". Expert Opinion on Therapeutic Patents 33 (12): 865–873. 2023. doi:10.1080/13543776.2023.2298833. PMID 38131310.
- ↑ "Efficacy of thymosin α1 for sepsis: A systematic review and meta-analysis of randomized controlled trials". Frontiers in Cellular and Infection Microbiology 15. 2025. doi:10.3389/fcimb.2025.1673959. PMID 40969554.
- ↑ "Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: A systematic review and meta-analysis". Frontiers in Immunology 16. 2025. doi:10.3389/fimmu.2025.1571456. PMID 40599771.
- ↑ "Thymosin Alpha 1 Plus Routine Treatment for the Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis". Journal of the College of Physicians and Surgeons Pakistan 34 (12): 1497–1507. 2024. doi:10.29271/jcpsp.2024.12.1497. PMID 39648386.
- ↑ "Thymosin alpha-1 treatment in chronic hepatitis B". Expert Opinion on Biological Therapy 15: 129–132. 2015. doi:10.1517/14712598.2015.1007948. PMID 25640173.
- ↑ "Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials". Alternative Therapies in Health and Medicine 30 (1): 6–12. 2024. PMID 38308608.
- ↑ "Aging and Thymosin Alpha-1". International Journal of Molecular Sciences 26 (23). 2025. doi:10.3390/ijms262311470. PMID 41373628.
- ↑ "Thymosin alpha1 use in adult COVID-19 patients: A systematic review and meta-analysis on clinical outcomes". International Immunopharmacology 114. 2023. doi:10.1016/j.intimp.2022.109584. PMID 36527881.
- ↑ "The efficacy of thymosin alpha-1 therapy in moderate to critical COVID-19 patients: A systematic review, meta-analysis, and meta-regression". Inflammopharmacology 31 (6): 3317–3325. 2023. doi:10.1007/s10787-023-01354-2. PMID 37845598.
- ↑ "Thymosin alpha 1 in the treatment of cancer: from basic research to clinical application". Int J Immunopharmacol 22 (12): 1067–76. 2000. doi:10.1016/s0192-0561(00)00075-8. PMID 11137613.
Further reading
- "Modulation of estrogen receptor activity by selective coregulators.". J. Steroid Biochem. Mol. Biol. 85 (2–5): 117–22. 2003. doi:10.1016/S0960-0760(03)00207-3. PMID 12943695.
- "Prothymosin alpha is phosphorylated by casein kinase-2.". FEBS Lett. 312 (2–3): 152–6. 1992. doi:10.1016/0014-5793(92)80924-6. PMID 1426245. Bibcode: 1992FEBSL.312..152B.
- "Prothymosin alpha enhances human and murine MHC class II surface antigen expression and messenger RNA accumulation.". J. Immunol. 148 (7): 1979–84. 1992. doi:10.4049/jimmunol.148.7.1979. PMID 1545115.
- "Prothymosin alpha expression in lymph nodes and tonsils: an optical and ultrastructural study.". Acta Anat (Basel) 143 (3): 219–22. 1992. doi:10.1159/000147251. PMID 1632187.
- "Prothymosin alpha enhances interleukin 2 receptor expression in normal human T-lymphocytes.". Int. J. Immunopharmacol. 13 (8): 1059–65. 1992. doi:10.1016/0192-0561(91)90156-2. PMID 1814846.
- "Thymosins: both nuclear and cytoplasmic proteins.". Eur. J. Biochem. 192 (3): 643–51. 1990. doi:10.1111/j.1432-1033.1990.tb19271.x. PMID 2209614.
- "Isolation and partial sequencing of the human prothymosin alpha gene family. Evidence against export of the gene products.". J. Biol. Chem. 264 (13): 7546–55. 1989. doi:10.1016/S0021-9258(18)83269-0. PMID 2708378.
- "The expression of prothymosin alpha gene in T lymphocytes and leukemic lymphoid cells is tied to lymphocyte proliferation.". J. Biol. Chem. 264 (15): 8451–4. 1989. doi:10.1016/S0021-9258(18)81807-5. PMID 2785990.
- "Molecular cloning of cDNA for human prothymosin alpha.". Proc. Natl. Acad. Sci. U.S.A. 83 (23): 8926–8. 1987. doi:10.1073/pnas.83.23.8926. PMID 3466166.
- "The human prothymosin alpha gene is polymorphic and induced upon growth stimulation: evidence using a cloned cDNA.". Proc. Natl. Acad. Sci. U.S.A. 83 (24): 9403–7. 1987. doi:10.1073/pnas.83.24.9403. PMID 3467312.
- "Prothymosin alpha in human blood.". Proc. Natl. Acad. Sci. U.S.A. 84 (13): 4465–9. 1987. doi:10.1073/pnas.84.13.4465. PMID 3474615. Bibcode: 1987PNAS...84.4465P.
- "Human prothymosin alpha: amino acid sequence and immunologic properties.". Arch. Biochem. Biophys. 250 (1): 197–201. 1986. doi:10.1016/0003-9861(86)90717-4. PMID 3532956.
- "Binding of human prothymosin alpha to the leucine-motif/activation domains of HTLV-I Rex and HIV-1 Rev.". Eur. J. Biochem. 233 (1): 48–54. 1995. doi:10.1111/j.1432-1033.1995.048_1.x. PMID 7588773.
- "Distribution of prothymosin alpha in rat and human adrenal cortex.". Anat. Rec. 239 (1): 88–94. 1994. doi:10.1002/ar.1092390110. PMID 7913591.
- "Prothymosin alpha gene in humans: organization of its promoter region and localization to chromosome 2.". Hum. Genet. 90 (6): 629–34. 1993. doi:10.1007/BF00202480. PMID 7916742.
- "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides.". Gene 138 (1–2): 171–4. 1994. doi:10.1016/0378-1119(94)90802-8. PMID 8125298.
- "Expression of alpha-thymosins in human tissues in normal and abnormal growth.". Proc. Natl. Acad. Sci. U.S.A. 90 (20): 9504–7. 1993. doi:10.1073/pnas.90.20.9504. PMID 8415730. Bibcode: 1993PNAS...90.9504T.
- "Phosphorylation of human and bovine prothymosin alpha in vivo.". Biochemistry 32 (17): 4587–96. 1993. doi:10.1021/bi00068a015. PMID 8485135.
- Rubtsov IuP; Vartapetian AB (1996). "[New intronless members of human prothymosin alpha genes]". Mol. Biol. (Mosk.) 29 (6): 1320–5. PMID 8592501.
