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Background And Mechanism Of Action — Explained

By Editorial Desk · published 2026-07-09 · last reviewed 2026-08-01 · Info

The short version of 胸腺素α1 fits in a sentence. The long version — which is the one that helps — is below.

This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.

Background and Mechanism of Action

Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.

Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.

Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.

分子身份与天然来源

20世纪70年代,研究者从胸腺提取物中纯化出多种小肽,Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤,产量低且成分复杂。随着固相肽合成技术成熟,实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上,并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。

市售的胸腺素α1通常以冻干粉形式提供,溶解后用于注射。其氨基酸组成包括多个酸性残基,因此在中性pH下带负电荷。该肽可溶于水和生理盐水,但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度,溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。

胸腺素α1(thymosin alpha 1,Tα1)是一种由28个氨基酸组成的酸性肽,N端被乙酰化,分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离,属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守,提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置,并非表示亚型编号。它既存在于胸腺,也存在于脾脏和淋巴结等免疫组织。

Thymosin-alpha-1 at a glance

PropertyValueNotes
Amino acid length28 residuesSingle chain with an acetylated N-terminus
Molecular massApproximately 3,108 DaSmall shifts occur with counter-ion and water content
Isoelectric pointAround 3.5Low value follows from the many acidic residues
Parent moleculeN-terminal region of prothymosin alphaFree circulating form in humans is not firmly established
Common synonymsThymalfasin; T alpha 1Older literature also uses the full spelled-out form

Research History and Clinical Assessment

Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.

Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.

Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.

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Background and Molecular Profile

The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.

Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.

Further detail

=== Nitric oxide === Nitric oxide (NO) is a major source of immunomodulation in rodents, and is produced by enzyme nitric oxide synthetase type 2 (NOS2) in the alveolar macrophage. NO inhibits tyrosine phosphorylation of the kinases involved in production of the interleukin-2 (IL-2) receptor, the expression of which is fundamental for T cell proliferation. In humans, however, NOS2 activity has been difficult to verify. There are two explanations for the lack of responsiveness in the promoter of human inducible nitric oxide synthetase (iNOS) to NO activation by lipopolysaccharides (LPS) + interferon gamma (IFNγ). The first is that there are various inactivating nucleotide variations in the human counterpart of the enhancer element that regulates LPS/IFNγ induced expression of the mouse NOS2 gene. The second is because of the absence of a nuclear factor in human macrophages that is required for optimum expression of gene NOS2 (LPS-inducible nuclear factor-kappa B/Rel complex). It is assumed that the difficulty in verifying NOS2 is due to a much more tightly controlled expression in human AMs as compared to that in the rodent AMs. NOS2 is part of an autoregulatory feedback loop, wherein an allergen or provoker stimulates inflammatory cytokine production, which in turn stimulates NO production, and NO down-regulates cytokine production.

=== In humans === Although generally considered safe to use, it is neurotoxic to humans in high doses. Pyrethroids like deltamethrin can also be an allergen that provokes asthma in some people. Deltamethrin temporarily attacks the nervous system of any animal with which it comes into contact. Skin contact can lead to tingling or reddening of the skin local to the application. If taken in through the eyes or mouth, the most common symptom is facial paraesthesia, which can feel like many different abnormal sensations, including burning, partial numbness, "pins and needles", skin crawling, etc. There is one case report describing chronic intoxication from pyrethroid insecticides leading to a syndrome clinically similar to motor neuron disease. There are no antidotes, and treatment must be symptomatic, as approved by a physician. Over time, deltamethrin is metabolized, with a rapid loss of toxicity, and passed from the body. A poison control center should be contacted in the event of an accidental poisoning. Deltamethrin is able to pass from a woman's skin through her blood and into her breast milk, although breastfeeding remains safe under prevailing conditions. In South Africa, residues of deltamethrin were found in breast milk, together with DDT, in an area that used DDT treatment for malaria control, as well as pyrethroids in small-scale agriculture. A 2015 study conducted in Brittany, France, found a negative correlation between deltamethrin exposure (measured through the presence of a metabolite in urine) and cognitive scores in infants.

==== Cancer ==== While traditional chemotherapy can effectively kill cancer cells, lack of specificity for discriminating normal cells and cancer cells in these treatments usually cause severe side effects. Numerous studies have demonstrated that RNAi can provide a more specific approach to inhibit tumor growth by targeting cancer-related genes (i.e., oncogene). It has also been proposed that RNAi can enhance the sensitivity of cancer cells to chemotherapeutic agents, providing a combinatorial therapeutic approach with chemotherapy. Another potential RNAi-based treatment is to inhibit cell invasion and migration. Compared with chemotherapy or other anti-cancer drugs, there are a lot of advantages of siRNA drug. SiRNA acts on the post-transcriptional stage of gene expression, so it does not modify or change DNA in a deleterious effect. SiRNA can also be used to produce a specific response in a certain type of way, such as by downgrading suppression of gene expression. In a single cancer cell, siRNA can cause dramatic suppression of gene expression with just several copies. This happens by silencing cancer-promoting genes with RNAi, as well as targeting an mRNA sequence. RNAi drugs treat cancer by silencing certain cancer promoting genes. This is done by complementing the cancer genes with the RNAi, such as keeping the mRNA sequences in accordance with the RNAi drug. Ideally, RNAi is should be injected and/or chemically modified so the RNAi can reach cancer cells more efficiently. RNAi uptake and regulation is controlled by the kidneys.

=== Other functions === Cholesterol translocation from outer to the inner mitochondrial membrane Activates mitochondrial cholesterol side-chain cleavage Import protein into mitochondrial matrix Anticoagulant function Modulates α-synuclein - malfunction of this process is thought to be a cause of Parkinson's disease.

Sources: en.wikipedia.org

Supporting material

Early medical texts, especially the Carakasaṃhitā and Suśrutasaṃhitā, are often claimed to contain early references to rasaśāstra. Where these texts use the word rasa, later commentators interpret rasa as mercury, despite the word having various other meanings. The earliest mentions of mercury are to the unprocessed substance and it is not until the 9th century Kalyāṇakāraka that we find recipes for purifying and calcination. The 13th century Śārṅgadharasaṃhitā also contains elaborate descriptions of the processing and uses of mercury. An important feature is the use of metals, including several that are toxic. In addition to mercury, gold, silver, iron, copper, tin, lead, zinc and bell metal are used. In addition to these metals, salts and other substances such as coral, seashells, and feathers are also used. The usual means used to administer these substances is by preparations called bhasma, Sanskrit for "ash". Calcination, which is described in the literature of the art as śodhana, "purification", is the process used to prepare these bhasma for administration. Sublimation and the preparation of a mercury sulfide are also in use in the preparation of its materia medica. A variety of methods are used to achieve this. One involves the heating of thin sheets of metal and then immersing them in oil (taila), extract (takra), cow urine (gomutra) and other substances. Others are calcined in crucibles heated with fires of cow dung (puttam). Ayurvedic practitioners believe that this process of purification removes undesirable qualities and enhances their therapeutic power.

== Selected publications == Balalaie, S.; Hashtroudi, M. S.; Arabanian, A. (2000). "One-pot synthesis of tetrasubstituted imidazoles catalyzed by zeolite HY and silica gel under microwave irradiation". Green Chemistry. 2 (6): 274–276. doi:10.1039/b006201o. Balalaie, S.; Bararjanian, M.; Amani, A. M.; Movassagh, B. (2006). "(S)-Proline as a neutral and efficient catalyst for the one-pot synthesis of tetrahydrobenzo [b] pyran derivatives in aqueous media". Synlett. 2006 (2): 263–266. doi:10.1055/s-2005-923606. Bararjanian, M.; Balalaie, S.; Rominger, F.; Movassagh, B.; Bijanzadeh, H. R. (2010). "Six-component reactions for the stereoselective synthesis of 3-arylidene-2-oxindoles via sequential one-pot Ugi/Heck carbocyclization/Sonogashira/nucleophilic addition". The Journal of Organic Chemistry. 75 (9): 2806–2812. doi:10.1021/jo902713x. PMID 20387848. Balalaie, S.; Bararjanian, M.; Hosseini, M.S.; Bigdeli, Z. (2006). "One-pot synthesis of 1,4-dihydropyridine derivatives in a solvent-free condition". Helvetica Chimica Acta. 89 (8): 1769–1773. doi:10.1002/hlca.200690161. Balalaie, S.; Sharafi-Kolkesh, A. (2003). "A novel and efficient one-pot synthesis of 2,4,6-triarylpyridines under solvent-free conditions". Zeitschrift für Naturforschung B. 58 (10): 1075–1077. doi:10.1515/znb-2003-1021.

== Pathophysiology == Atherogenesis is the developmental process of atheromatous plaques. It is characterized by arterial remodeling, leading to the subendothelial accumulation of fatty substances called plaques. The buildup of an atheromatous plaque is a slow process, developed over several years through a complex series of cellular events occurring within the arterial wall and in response to several local vascular circulating factors. One recent hypothesis suggests that, for unknown reasons, leukocytes, such as monocytes or basophils, begin to attack the endothelium of the artery lumen in cardiac muscle. The ensuing inflammation leads to the formation of atheromatous plaques in the arterial tunica intima, a region of the vessel wall located between the endothelium and the tunica media. Chronic inflammation within the arterial wall, driven by immune cells (e.g., macrophages), accelerates atherosclerotic plaque instability by promoting collagen breakdown and thinning the fibrous cap, increasing the likelihood of rupture and thrombosis. The bulk of these lesions is made of excess fat, collagen, and elastin. At first, as the plaques grow, only wall thickening occurs without narrowing. Stenosis is a late event, which may never happen and is often the result of repeated plaque rupture and healing responses, not just the atherosclerotic process. Autopsy studies have shown that the prevalence of coronary artery atherosclerosis in males from the United States, with an average age of 22.1 years, who died in war, ranges from 45% to 77.3%.

After the prey has been digested, the cone snail will regurgitate any indigestible material, such as spines and scales, along with the harpoon. There is always a radular tooth in the radular sac. A tooth may also be used in self-defense when the snail feels threatened. The harpoon attack of the species Conus catus has been found to be one of the fastest complete movements recorded in animals, with a maximum speed of 90 km/h (56 mph), an acceleration of 400,000 m/s2, and a deceleration of 700,000 m/s2. The speed of other animals such as the peacock mantis shrimp and the trap-jaw ant was measured at the free end of a fixed appendage, while the speed of the harpoon was measured from its base and traveling inside the proboscis. The reason for this speed relies in hydrostatic pressure by the fluid inside the proboscis which propels the harpoon inside until it is almost completely out. A sphincter acts as a valve to keep fluid in the proximal half and in the distal half a constriction of ephitelial tissue together with a thicker harpoon base helps to build up hydrostatic pressure when the sphincter opens. The deceleration may help release the venom from the harpoon.

On 18 March 2021, German regional leaders including State Premiers and the mayor of Berlin called for the swift approval of the Russian vaccine by the European Medicines Agency to counteract the acute shortages of effective vaccines in Europe. German medical experts have recommended its approval also, and consider the Sputnik Vaccine "clever" and "highly safe". On 19 March 2021, the Philippine Food and Drug Administration granted emergency use authorization for Sputnik V, the fourth COVID-19 vaccine to be given authorization. The Philippine government planned to buy 20 million doses of the vaccine. On 12 April 2021, India approved the use of Sputnik V vaccine for emergency use against COVID-19 based on strong immunogenicity data. As of 12 April 2021, 62 countries had granted Sputnik V emergency use authorization. On 27 April 2021, Bangladesh approved the use of Sputnik V vaccine for emergency use. On 30 April 2021, Turkey and Albania approved the use of Sputnik V vaccine for emergency use.

Sources: en.wikipedia.org

Notes from published material

A monomer ( MON-ə-mər; mono-, "one" + -mer, "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization.

== Later life and recognition == Smolková-Keulemansová became one of the leading experts in the field of chromatography. She was the first professor of chemistry in the Czech Republic and one of the first in Europe. Not only did she continue her studies in chemistry, but she also focused on polarography, a PhD focused on gas chromatography and a DrSc concentrated on inclusion compounds in chromatography. In the early 1970s, inclusion complex formations in selective analytical separations became a major focus of Smolková-Keulemansová's, her first choice being cyclodextrins, but moving on with urea and thiourea for the separation of isomers. Her research on cyclodextrins started soon after her methods focused on gas chromatography, high-performance liquid chromatography and electromigration. Her research became more widespread and she was asked to add many monographs on cyclodextrins, one of them being for a compendium on supramolecular chemistry edited by Jean-Marie Lehn. She has written and co-written 140 original papers and numerous reviews and has contributed to many books, including her work in Journal of High-Resolution Chromatography, "A Few Milestones on the Journey of Chromatography", and an article in the journal Chromatographia, "Study of retention of isomeric aromatic hydrocarbons on GTCB and cyclodextrins". Smolková-Keulemansová died on 27 February 2024, at the age of 96.

=== Follicular phase === GnSAF prevents a pre-ovulatory surge in LH during this time, allowing sufficient time for the dominant follicle to mature before ovulation. At the start of the follicular phase, high serum FSH concentrations stimulate the development and proliferation of the granulosa cells of the small antral follicles, resulting in a steady increase in GnSAF biosynthesis. The relatively high GnSAF bioactivity dampens the response of the pituitary gland to GnRH by antagonising the sensitising effects of estradiol on the pituitary gland. The GnRH pulse, in the presence of GnSAF, is not frequent or potent enough to stimulate LH secretion from the anterior pituitary above basal levels.

Some medical organizations take the position that it carries prophylactic health benefits that outweigh the risks, while others hold that its medical benefits are not sufficient to justify it. Circumcision is one of the world's most common and oldest medical procedures, with 37–39% of men globally circumcised. Prophylactic usage originated in England during the 1850s and has since spread globally, becoming established as a way to prevent sexually transmitted infections. Beyond use as a prophylactic or treatment option in healthcare, circumcision plays a major role in many of the world's cultures and religions, most prominently Judaism and Islam. Circumcision is among the most important commandments in Judaism and considered obligatory. In some African and Eastern Christian denominations male circumcision is required. It is widespread in the United States, South Korea, the Philippines, Israel, Muslim-majority countries, and most of Africa. It is relatively rare for non-religious reasons in Latin America, Europe, Australia, most of Asia, and parts of Southern Africa. The origin of circumcision is not known with certainty, but the oldest documentation comes from ancient Egypt.

=== Courier delivery === Courier-delivered flowers (also sometimes called grower-direct or Flowers By Post) are assembled into bunches at the farm or in the warehouse of an importer or distributor; they are then placed in cardboard boxes and shipped direct to the recipient via overnight couriers. The advantage of such a service is that because the flowers are shipped from the farm or importer they can be fresher although temperature fluctuations en route and shipping conditions may negate the benefit. Recipients are responsible to unpack, clean, condition and arrange courier-delivered flowers. Few companies in fact ship flowers direct to the consumer from the farm. Most online flower retails such as ProFlowers, Interflora, Teleflora, FTD typically function as order gatherers and will work with local florists to have the order delivered.

Sources: en.wikipedia.org

Frequently asked questions

Is thymosin alpha-1 a hormone?

It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.

How does it relate to prothymosin alpha?

Prothymosin alpha is a much larger acidic protein, roughly 111 to 113 residues long, and the thymosin alpha-1 sequence matches its N-terminal region. The small peptide is therefore best understood as a fragment of that parent protein rather than a separate gene product.

Which clinical areas have been studied?

Trials and clinical reports have examined chronic hepatitis B and C, use as a vaccine adjuvant, and supportive treatment in some immunodeficiency and oncology settings. Results vary by indication, and regulatory approval differs between countries.

胸腺素α1是激素吗?

它不是经典的内分泌激素,而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现,而非经血液循环作用于远隔器官。

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