细胞因子 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 2026-01-16 and is reviewed periodically as new material appears.
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.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
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.
临床研究将Tα1用于慢性病毒感染、肿瘤辅助治疗和疫苗佐剂等场景。部分试验报告了免疫学指标改善，但临床终点获益在不同研究中并不一致。系统综述指出，研究间在人群、剂量和联合方案上差异较大，难以汇总结论。因此，Tα1的确切临床地位仍属开放问题，需要更多高质量随机对照试验来澄清。其机制研究也需从体外实验向体内模型推进。
胸腺素α1对免疫系统的影响涉及多种细胞类型。研究表明，它可促进未成熟T细胞向成熟T细胞分化，并增强T细胞对抗原刺激的增殖反应。树突状细胞在Tα1存在下表达更高水平的共刺激分子，从而更有效地呈递抗原。此外，自然杀伤细胞的活性也观察到上升。这些效应并非直接杀伤病原体，而是调节宿主免疫应答的强度与方向。
在信号层面，Tα1可能通过Toll样受体等模式识别受体发挥作用。部分实验显示，它能激活髓样分化因子88依赖的通路，进而促进核因子κB进入细胞核。这导致白细胞介素2、干扰素γ和白细胞介素12等细胞因子的转录增加。这些细胞因子偏向辅助性T细胞1型应答，有助于细胞免疫。然而，具体受体和结合位点尚未完全确定，不同实验模型的结果存在差异。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
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.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
==== Benzamides ==== Amisulpride (Socian) ‡ – Selective dopamine antagonist. Higher doses (greater than 400 mg) act upon post-synaptic dopamine receptors resulting in a reduction in the positive symptoms of schizophrenia, such as psychosis. Lower doses, however, act upon dopamine autoreceptors, resulting in increased dopamine transmission, improving the negative symptoms of schizophrenia. Lower doses of amisulpride have also been shown to have antidepressant and anxiolytic effects in non-schizophrenic patients, leading to its use in dysthymia and social phobias. Nemonapride † – Used in Japan. Remoxipride # – Has a risk of causing aplastic anaemia and, hence, has been withdrawn from the market worldwide. It has also been found to possess relatively low (virtually absent) potential to induce hyperprolactinaemia and extrapyramidal symptoms, likely attributable to its comparatively weak binding to (and, hence, rapid dissociation from) the D2 receptor. Sultopride – An atypical antipsychotic of the benzamide chemical class used in Europe, Japan, and Hong Kong for the treatment of schizophrenia. It was launched by Sanofi-Aventis in 1976. Sultopride acts as a selective D2 and D3 receptor antagonist.
=== Dietary therapy === Initial attempts at dietary therapy in ALD involved restricting the intake of very-long chain fatty acids (VLCFA). Dietary intake is not the only source for VLCFA in the body, as they are also synthesized endogenously. This dietary restriction did not impact the levels of VLCFA in plasma and other body tissues. After the realization that endogenous synthesis was an important contribution to VLCFA in the body, efforts at dietary therapy shifted to inhibiting these synthetic pathways in the body. The parents of Lorenzo Odone, a boy with ALD, spearheaded efforts to develop a dietary treatment to slow the progression of the disease. They developed a mixture of unsaturated fatty acids (glycerol trioleate and glyceryl trierucate in a 4:1 ratio), known as Lorenzo's oil that inhibits elongation of saturated fatty acids in the body. Supplementation with Lorenzo's oil has been found to normalize the VLCFA concentrations in the body, although its effectiveness at treating the cerebral manifestations of the disease is still controversial and unproven. Trials with Lorenzo's oil have shown that it does not stop the neurological degradation in symptomatic patients, nor does it improve adrenal function, but asymptomatic patients, and speculatively AMN variants without cerebral involvement, as well as female carriers may benefit from early intake of oleic and erucic acids in addition to VLCFA restriction.
=== tRNA === While consensus secondary and tertiary structures have been observed in tRNAs, there has not been evidence of tRNAs creating a quaternary structure thus far. Of note, it has been observed through high resolution imaging that tRNA interacts with the quaternary structure of bacterial 70S ribosome and other proteins.
Generally, American black bears are largely crepuscular in foraging activity, though they may actively feed at any time. Up to 85% of their diet consists of vegetation, though they tend to dig less than brown bears, eating far fewer roots, bulbs, corms and tubers than the latter species. When initially emerging from hibernation, they will seek to feed on carrion from winter-killed animals and newborn ungulates. As the spring temperature warms, American black bears seek new shoots of many plant species, especially new grasses, wetland plants and forbs. Young shoots and buds from trees and shrubs during the spring period are important to bears emerging from hibernation, as they assist in rebuilding muscle and strengthening the skeleton and are often the only digestible foods available at that time. During summer, the diet largely comprises fruits, especially berries and soft mast such as buds and drupes. During the autumn hyperphagia, feeding becomes virtually the full-time task. Hard mast becomes the most important part of the diet in autumn and may even partially dictate the species' distribution. Favored mast such as hazelnuts, oak acorns and whitebark pine nuts may be consumed by the hundreds each day by a single bear during the fall. During the fall period, bears may also habitually raid the nut caches of tree squirrels. Also extremely important in fall are berries such as huckleberries and buffalo berries.
Biotechniques Laboratory electrophoresis demonstration, from the University of Utah's Genetic Science Learning Center Discontinuous native protein gel electrophoresis[link removed] Drinking straw electrophoresis How to run a DNA or RNA gel Animation of gel analysis of DNA restriction Step by step photos of running a gel and extracting DNA A typical method from wikiversity
Sources: en.wikipedia.org
== See also == Alim-Louis Benabid Brain computer interfacing (BCI) BrainGate International Neuromodulation Society Interventional pain management North American Neuromodulation Society Neuroimmunology Neuromodulation (journal) Neuroprosthetics Neurotechnology Neurotherapy Neurostimulation Non-invasive cerebellar stimulation Optogenetics Visual prosthesis
== See also == Nazi architecture – Style promoted by the Nazis Palace of the Soviets – Unrealised Soviet project during Stalin's rule Reichstag building – Seat of the federal parliament of Germany Symbolism of domes
The heart functions as a pump in the circulatory system to provide a continuous flow of blood throughout the body. This circulation consists of the systemic circulation to and from the body and the pulmonary circulation to and from the lungs. Blood in the pulmonary circulation exchanges carbon dioxide for oxygen in the lungs through the process of respiration. The systemic circulation then transports oxygen to the body and returns carbon dioxide and relatively deoxygenated blood to the heart for transfer to the lungs. The right heart collects deoxygenated blood from two large veins, the superior and inferior venae cavae. Blood collects in the right and left atrium continuously. The superior vena cava drains blood from above the diaphragm and empties into the upper back part of the right atrium. The inferior vena cava drains the blood from below the diaphragm and empties into the back part of the atrium below the opening for the superior vena cava. Immediately above and to the middle of the opening of the inferior vena cava is the opening of the thin-walled coronary sinus. Additionally, the coronary sinus returns deoxygenated blood from the myocardium to the right atrium. The blood collects in the right atrium. When the right atrium contracts, the blood is pumped through the tricuspid valve into the right ventricle. As the right ventricle contracts, the tricuspid valve closes and the blood is pumped into the pulmonary trunk through the pulmonary valve.
=== Enzyme substitutes === In 2018, the FDA approved an enzyme substitute called pegvaliase which metabolizes phenylalanine. It is for adults who are poorly managed on other treatments. Tetrahydrobiopterin (BH4) (a cofactor for the oxidation of phenylalanine) when taken by mouth can reduce blood levels of this amino acid in some people.
Sources: en.wikipedia.org
=== Hormonal === Inhibition of ceramide synthesis with myriocin in obese mice may lead to both improved leptin signaling and decreased insulin resistance by decreasing SOCS-3 expression. An elevated level of ceramide can cause insulin resistance by inhibiting the ability of insulin to activate the insulin signal transduction pathway and/or via the activation of JNK.
=== Environmental triggers === Environmental factors, such as glandular viral infection, could prompt epithelial cells to activate the HLA-independent innate immune system through toll-like receptors. Although several infectious, exogenous agents have been implicated in the pathogenesis of Sjögren's disease, such as Epstein-Barr virus (EBV), human T-lymphotropic virus 1, and hepatitis C virus, their association with Sjögren's disease appears weak. While EBV is present in the salivary glands of normal individuals, a high incidence of EBV reactivation in Sjögren's patients has been reported with increased levels of EBV DNA. This indicates viral reactivation and the inability of lymphoid infiltrates to control EBV replication in Sjögren's disease, leading to the initiation or perpetuation of an immune response in target organs. Nonetheless, exactly how EBV reactivation is induced in lesions of patients with Sjögren's disease, and which specific molecular mechanisms are involved in the process of viral reactivation, remain to be clarified.
Pterygoplichthyini is a tribe of catfishes (order Siluriformes) of the family Loricariidae. It includes two genera, Pterygoplichthys and the currently undescribed genus referred to as the Hemiancistrus annectens group, This group was earlier misspelled as Pterygoplichthini. Pterygoplichthyines are known from nearly the entire range of loricariids except for the Guyanas and coastal streams in southeastern Brazil. although later work by the same authority, and his co-authors, placed this group among the genus Hypostomus. Pterygoplichthyini is sister to the tribe Ancistrini, which shares the derived presence of an evertible patch of plates on the cheek. Pterygoplichthys and the H. annectens group differ most obviously in the number of dorsal fin rays (7 in the H. annectens group and 9+ in Pterygoplichthys). The two genera are supported as sisters by only one derived characteristic: a modified stomach that is attached to the abdominal wall by a net of connective tissue. This modified stomach allows these fish to breathe air. The stomach is vascularized. A white net of connective tissue surrounds the organ, leaving a circular area in the middle of the stomach free; this connective tissue firmly holds the stomach to the body wall and is better developed in adults. It may also function as a hydrostatic organ, allowing the fish to remain buoyant midwater.
Rachel Frances Shaw (born 1981 or 1982) is an American actress, writer and director. She is best known for playing Bridgette Bird on the Showtime series SMILF, based on the 2015 short film of the same title, which she wrote, directed and starred in. Shaw is also known for playing Mary Jo Cacciatore on the 2010–2011 Spike TV series Blue Mountain State, and her recurring role as Shayla Nico in the first season of the USA Network television series Mr. Robot.
239Pu is a key fissile component in nuclear weapons, due to its ease of fission and availability. Encasing the bomb's plutonium pit in a tamper (a layer of dense material) decreases the critical mass by reflecting escaping neutrons back into the plutonium core. This reduces the critical mass from 16 kg to 10 kg, which is a sphere with a diameter of about 10 centimeters (4 in). This critical mass is about a third of that for uranium-235. The Fat Man plutonium bombs used explosive compression of plutonium to obtain significantly higher density than normal, combined with a central neutron source to begin the reaction and increase efficiency. Thus only 6 kg of plutonium was needed for an explosive yield equivalent to 20 kilotons of TNT. Hypothetically, as little as 4 kg of plutonium—and maybe even less—could be used to make a single atomic bomb using very sophisticated assembly designs.
Sources: en.wikipedia.org
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.
Thymosin alpha-1 is a single defined 28-residue peptide, while the broader family includes unrelated peptides such as thymosin beta-4. The shared name reflects historical isolation from thymus tissue rather than a common structure. Confusion between the two is common in older literature.
No single pathway fully accounts for its reported effects. Several studies describe interaction with innate immune receptors and downstream cytokine changes, but the complete picture is not settled. Open questions remain about which effects occur at physiological concentrations.
它促进未成熟T细胞分化并增强成熟T细胞的增殖与细胞因子分泌。这些作用有助于放大抗原特异性免疫应答。