vaccine adjuvant raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-19 and is reviewed periodically as new material appears.
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.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| First described | 1977 | Reported as a component of thymosin fraction 5 |
| Sequence length | 28 amino acids | N-terminal residue is acetylated |
| Net charge at neutral pH | Negative | Reflects a high proportion of acidic residues |
| Principal studied uses | Chronic hepatitis B and vaccine adjuvant | Research uses outnumber approved indications |
| Regulatory status | Approved in a limited number of countries | Not approved in the United States or most of Europe |
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.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Secretin receptor family (class B GPCR subfamily) consists of secretin receptors regulated by peptide hormones from the glucagon hormone family. In early classifications, adhesion G protein-coupled receptors were included as part of the secretin receptor family, but in some more recent classification systems they are considered a distinct family (see for example: GRAFS). The secretin-receptor family of GPCRs include vasoactive intestinal peptide receptors and receptors for secretin, calcitonin and parathyroid hormone/parathyroid hormone-related peptides. These receptors activate adenylyl cyclase and the phosphatidyl-inositol-calcium pathway. The receptors in this family have seven transmembrane helices, like rhodopsin-like GPCRs. However, there is no significant sequence identity between these two GPCR families and the secretin-receptor family has its own characteristic 7TM signature. The secretin-receptor family GPCRs exist in many animal species. Data mining with the Pfam signature has identified members in fungi, although due to their presumed non-hormonal function they are more commonly referred to as Adhesion G protein-coupled receptors, making the Adhesion subfamily the more basal group. Three distinct sub-families (B1-B3) are recognized.
=== Dance === Alongside her screen career, Kallingal has maintained an active presence as a performer and choreographer. In 2014 she established Mamangam, a dance studio in Kochi, which closed in 2021 due to the COVID-19 pandemic. She subsequently reconstituted it as Mamangam Dance Company, which continues to produce and tour contemporary dance work. In November 2023, Mamangam Dance Company presented its debut full-length contemporary dance production, Neythe — Dance of the Weaves, at the Fine Arts Society Hall, Kochi. The 35-minute work paid tribute to the handloom weavers of Chendamangalam and was inspired by the displacement of livelihoods after the 2018 Kerala floods. The production was staged at the International Theatre Festival of Kerala in Thrissur in March 2025. Kallingal also created Nayika, a one-hour dance production tracing a century of women in Malayalam cinema, beginning with a tribute to P. K. Rosy, the industry's first actress.
== Metabolism == Safrole can undergo many forms of metabolism. The two major routes are the oxidation of the allyl side chain and the oxidation of the methylenedioxy group. The oxidation of the allyl side chain is mediated by a cytochrome P450 complex, which will transform safrole into 1′-hydroxysafrole. The newly formed 1′-hydroxysafrole will undergo a phase II drug metabolism reaction with a sulfotransferase enzyme to create 1′-sulfoxysafrole, which can cause DNA adducts. A different oxidation pathway of the allyl side chain can form safrole epoxide. So far, this has only been found in rats and guinea pigs. The formed epoxide is a small metabolite due to the slow formation and further metabolism of the compound. An epoxide hydratase enzyme will act on the epoxide to form dihydrodiol, which can be secreted in urine. The metabolism of safrole through the oxidation of the methylenedioxy proceeds via the cleavage of the methylenedioxy group. This results in two major metabolites: allylcatechol and its isomer, propenylcatechol. Eugenol is a minor metabolite of safrole in humans, mice, and rats. The intact allyl side chain of allylcatechol may then be oxidized to yield 2′,3′-epoxypropylcatechol. This can serve as a substrate for an epoxide hydratase enzyme, and will hydrate the 2′,3′-epoxypropylcatechol to 2′,3′-dihydroxypropylcatechol. This new compound can be oxidized to form propionic acid (PPA), which is a substance that is related to an increase in oxidative stress and glutathione S-transferase activity.
Sources: en.wikipedia.org
Robert H. Christenson, PhD, DABCC, FACB, is the current President of the American Association for Clinical Chemistry, AACC. As of 2026, he is a professor of pathology and professor of medical and research technology at the University of Maryland School of Medicine in Baltimore. He is a member of the editorial boards of Clinical Chemistry and the Journal of Clinical and Laboratory Analysis, and associate editor of Clinical Biochemistry.
Brother Zachariah — formerly known as James "Jem" Carstairs, a Silent Brother, and the former parabatai of Will Herondale, who acts as a kind of uncle to James, Lucie and the others. He is also a first cousin to Cordelia and Alastair. Barbara Lightwood — The eldest child of Gideon Lightwood and Sophie Collins. Growing up, Barbara had the perfect Sight, the ability to see past glamours. She has an understanding with Oliver Hayward, whose family runs the York Institute. Barbara was very affectionate and protective over Thomas—to the point where he found it smothering—and was often considered more gentle than her sister. She was somewhat of a romantic, and wanted to become a dutiful wife rather than a strong Shadowhunter. During a demon attack in Regents Park, Barbara was bitten and collapsed. In her final moments, she was delirious and lashed out, clawing at Oliver who had been crying by her bedside. This unknowingly spread the infection to Oliver who fell ill and died shortly after. Thomas and the others dedicated themselves to not only making a cure but finding and putting an end to the demon attacks in her name. Eugenia Lightwood — The second child of Gideon Lightwood and Sophie Collins. Like Barbara, Eugenia was very affectionate and protective over Thomas, to the point where he found it smothering, and wants to become a dutiful wife rather than a strong Shadowhunter. She is considered stubborn and rebellious. Eugenia was seemingly dubbed "ruined" as she had apparently been found alone with a gentleman whom did not later propose to her.
== Chemistry == Zalsupindole, also known as (R)-5-methoxy-N,N-dimethyl-α-methylisotryptamine, is a substituted isotryptamine derivative. It is a combined derivative of 5-methoxy-N,N-dimethylisotryptamine (5-MeO-isoDMT) and α-methylisotryptamine (isoAMT). Another related compound is 6-methoxy-N,N-dimethylisotryptamine (6-MeO-isoDMT). Zalsupindole is a close isotryptamine analogue of α,N,N,O-tetramethylserotonin (α,N,N,O-TMS or 5-MeO-α,N,N-TMT).
Sources: en.wikipedia.org
Trials differ in patient population, dose schedule, background treatment, and the endpoints used to judge success. Many are small and single-center, so random variation can dominate the reported effects.
Authorization is limited to a small number of countries and covers specific indications such as chronic hepatitis B and vaccine adjuvant use. Availability and labelling differ by jurisdiction.
Most reviews describe it as an immunomodulatory agent with an uncertain clinical effect. They generally call for larger, better-controlled trials before firm conclusions are drawn.
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。