免疫组织 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 2026-02-06 and is reviewed periodically as new material appears.
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.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | About 3.1 kDa | 28 residues, N-terminally acetylated |
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in aqueous buffers |
| Storage temperature | 2 to 8 °C | Protect from light and moisture |
| Common synonyms | Thymalfasin; Tα1 | Same peptide sequence |
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。
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。
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
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.
James Lamar Wittliff (born June 15, 1938) also known as Jim Wittliff, is an American Biochemist and Professor Emeritus of Biochemistry & Molecular Genetics at the University of Louisville. He was Chairman of the Department of Biochemistry at the University of Louisville School of Medicine and Dentistry from 1976-1983. Wittliff's laboratory was designated the National Reference Facility by the National Cancer Institute for performing quality assurance surveys of receptor biomarker testing in breast cancers for cooperative clinical trial groups in the United States and Canada. He is the co-developer with NEN/DuPont of the 1st FDA approved tests for quantifying levels of estrogen and progestin receptor proteins.
=== Frank H. Field and Joe L. Franklin Award for Outstanding Achievement in Mass Spectrometry (since 1985) === 2021 Veronica M. Bierbaum 2020 Kimberly A. Prather 2019 Jennifer S. Brodbelt 2018 Carol Vivien Robinson 2017 Vicki H. Wysocki 2015 Hilkka I. Kenttämaa 2010 Catherine E. Costello 2008 Catherine C. Fenselau 1990 Marjorie G. Horning
== Further reading == Rees, Jonathan. Refrigeration Nation: A History of Ice, Appliances, and Enterprise in America (Johns Hopkins University Press; 2013) 256 pages Refrigerators and food preservation in foreign countries. United States Bureau of Statistics, Department of State. 1890.
In late 1988, tensions between the United States and Panama were extremely high with the Panamanian leader, Manuel Noriega, calling for the dissolution of the agreement that allowed the United States to have bases in his country. In December 1989 President George H. W. Bush activated the planning section for Operation Just Cause/Promote Liberty. Just Cause was the portion of the mission to depose Noriega and return Panama to democracy. Originally scheduled to begin at 0200 hrs. on 20 December, it actually kicked off at 2315 hrs when part of a Special Forces detachment that was waiting for the signal to begin was discovered above a gate above a Panamanian checkpoint. Just Cause was the first mission to have a very large contingent of Special Operations Forces on the ground. The units that were involved with the mission were as follows: Task Force Green (Delta Force), Task Force Black (7th SFG), 5th SFG, 3rd SFG, 4th PSYOP Group, the reinforced 1st Brigade of the 82nd Airborne Division, and all three battalions of the 75th Rangers, and numerous other units from other forces such as the Navy SEALs, Marine Force Recon, and Air Force Combat Control Teams. Of the 23 US troops who died in the invasion four were Navy SEALs. The invasion was successful at deposing Noriega, but led to widespread looting and lawlessness in the following weeks.
Sources: en.wikipedia.org
n RCHNHC(O)OC(O) → [N(H)CH(R)CO)]n + n CO2 Poly-L-lysine has been prepared from N-carbobenzyloxy-α-N-carboxy-L-lysine anhydride, followed by deprotection with phosphonium iodide. Peptide synthesis from NCAs does not require protection of the amino acid functional groups. N-Substituted NCAs, such as sulfenamide derivatives have also been examined. The ring-opening polymerization of NCAs is catalyzed by metal catalysts. The polymerization of NCA’s have been considered as a prebiotic route to polypeptides. NCAs can also be used to form amides and lactams by reaction of carboxylic acids and isocyanates.
== Cause == Mechanical tension on a wound has been identified as a leading cause of hypertrophic scar formation. When a normal wound heals, the body produces new collagen fibers at a rate that balances the breakdown of old collagen. Hypertrophic scars are thick, red to brown in coloration, and may be itchy or painful. They do not extend beyond the boundary of the original wound but may continue to rise or thicken for up to six months. Hypertrophic scars usually heal and fade over one to two years. Hypertrophic scars may cause distress due to their appearance or the intensity of itchiness. They can also restrict movement if located close to a joint. Some people, such those with Ehlers–Danlos syndrome, may have an inherited tendency to develop hypertrophic scarring.
Bethlem myopathy is predominantly an autosomal dominant myopathy, classified as a congenital form of limb-girdle muscular dystrophy. There are two types of Bethlem myopathy, based on which type of collagen is affected. Bethlem myopathy 1 (BTHLM1) is caused by a mutation in one of the three genes coding for type VI collagen. These include COL6A1, COL6A2, and COL6A3. It is typically autosomal dominant, though uncommonly can be autosomal recessive. Bethlem myopathy 2 (BTHLM2), formerly known as myopathic-type Ehlers–Danlos syndrome, is caused by a mutation on the COL12A1 gene coding for type XII collagen. It is autosomal dominant. In 2017, an international workshop proposed a redefined criteria and naming system for limb-girdle muscular dystrophies. Bethlem myopathy 1 (collagen VI) was included into the proposed list and renamed LGMDD5 for autosomal dominant mutations and LGMDR22 for recessive mutations. Bethlem myopathy 2 (collagen XII) was not addressed. Gowers's sign, toe walking, multiple contractures of the joints (especially the fingers: 'Bethlem sign'), skin abnormalities, and muscle weakness (proximal more than distal) are typical signs and symptoms of the disease. Initially, in early childhood, there may also be joint laxity. There is no cardiac involvement in either Bethlem myopathy 1 or 2, which helps to differentiate it from Emery–Dreifuss muscular dystrophy. Currently there is no cure for the disease and symptomatic treatment is used to relieve symptoms and improve quality of life.
=== Halides === The colorless curium(III) fluoride (CmF3) can be made by adding fluoride ions into curium(III)-containing solutions. The brown tetravalent curium(IV) fluoride (CmF4) on the other hand is only obtained by reacting curium(III) fluoride with molecular fluorine:
=== Western medicine === There has been a recent increase in research to confirm the efficacy of some of the claimed benefits of E. sinensis, as well as find additional possible uses within the medical field. Testing on immuno-suppressed mice has showed positive effects on immune system function. This points to an area of future research for human use. Chitosan extraction for utilization in production of nanofiber membranes used for wound dressings. Research around nanofiber dressings has increased in recent years. Shrimp and crab chitosan is usually utilized, E. sinensis chitosan extraction has aims to address seasonal and regional restrictions.
Sources: en.wikipedia.org
Human (and other eukaryote) cells can produce ATP from glucose without oxygen in a process called glycolysis. This is not as efficient as respiration, but provides a high instantaneous output, and is hence used by some muscle cells. Glycolysis consumes ADP, Pi, glucose, and NAD+ to produce ATP, pyruvate, and NADH. Through lactate fermentation, pyruvate and NADH are turned into lactate and NAD+, thereby regenerating the NAD+ required for more glycolysis. During the 1990s, the lactic acid hypothesis was created to explain why people experienced burning or muscle cramps that occurred during and after intense exercise. The hypothesis proposes that a lack of oxygen in muscle cells results in a switch from cellular respiration to fermentation. Lactic acid created as a byproduct of fermentation of pyruvate from glycolysis accumulates in muscles causing a burning sensation and cramps. Research from 2006 has suggested that acidosis isn't the main cause of muscle cramps. Instead cramps may be due to a lack of potassium in muscles, leading to contractions under high stress. Animals, in fact, do not produce lactic acid during fermentation. Despite the common use of the term lactic acid in the literature, the byproduct of fermentation in animal cells is lactate. Another change to the lactic acid hypothesis is that when sodium lactate is inside of the body, there is a higher period of exhaustion in the host after a period of exercise.
=== Size-Exclusion Chromatography (Gel Filtration) === Size-exclusion chromatography separates proteins based on their size. The stationary phase is composed of porous beads that allow smaller molecules to enter the pores while larger molecules pass around them. As a result, larger proteins elute first, followed by smaller ones. This method is particularly useful for desalting or removing small contaminants from protein samples.
== Rivalries == Essendon's biggest rivals are Carlton, Richmond, and Collingwood, as these teams and Essendon are the four biggest and most supported clubs in Victoria. Matches between the clubs are often close regardless of form and ladder positions. If out of the race themselves, all four have the desire to deny the others a finals spot or a premiership. Essendon also has a fierce rivalry with Hawthorn, stemming from excessive on-field violence in the 1980s, perhaps reaching its zenith with the infamous Line in the Sand Match in 2004. Additionally, Essendon has a three-decade rivalry with the West Coast Eagles.
It has been found that the combination of emulsifiers might prevent particle agglomeration more efficiently. An SLN is generally spherical and consists of a solid lipid core stabilized by a surfactant. The core lipids can be fatty acids, acylglycerols, waxes, and mixtures of these surfactants. Biological membrane lipids, such as phospholipids, sphingomyelins, bile salts (sodium taurocholate), and sterols (cholesterol) are used as stabilizers. Biological lipids having minimum carrier cytotoxicity and the solid state of the lipid permit better controlled drug release due to increased mass transfer resistance.
Sources: en.wikipedia.org
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.
It is a chain of 28 amino acids, with an acetyl group attached to the first serine residue. The synthetic version replicates this sequence. Its molecular mass is about 3,108 daltons.