The short version of Immune modulation fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-27. Anything still debated is marked as such rather than presented as settled.
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.
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。
| 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 |
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 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.
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 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.
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.
The idea of the great chain, as well as the derived "missing link", was abandoned in early 20th-century science, as the notion that embryonic development recapitulates "lower" forms was abandoned in biology, to be replaced by an evolutionary tree supplemented by horizontal gene transfer, as well as more complex web structures. The idea of a certain sequence from lower to higher complexity and fitness is still popular, as is the idea of progress in biology.
The water cycle (known scientifically as the hydrologic cycle) is the continuous exchange of water within the hydrosphere, between the atmosphere, soil water, surface water, groundwater, and plants. Water moves perpetually through each of these regions in the water cycle consisting of the following transfer processes:
=== Urinary tract infection === People with diabetes show an increased rate of urinary tract infection. The reason is that bladder dysfunction is more common in people with diabetes than in people without diabetes due to diabetes nephropathy. When present, nephropathy can cause a decrease in bladder sensation, which in turn can cause increased residual urine, a risk factor for urinary tract infections.
The low budget of the project proved to be a significant challenge, as well as the unique challenges of working with child actors. The producers wanted the style of the series to reflect trends begun in other popular and innovative TV shows such as Sesame Street and Laugh-In. Puppetry and animation were frequently used. Sometimes one or two of the kids would conduct "man-on-the-street" interviews, asking ordinary citizens about nutrition-related topics. All of the music, including the theme song and the various songs sung by the kids during an episode (many times in musical "romps" reminiscent of the ones seen on The Monkees TV series), were composed and arranged by Washington, DC musician and recording engineer Paul Brier, and performed by a rock combo credited on screen as "The Eye". Mulligan Stew premiered on October 4, 1972, during the National 4-H Week at the National 4-H Center in Washington, DC. The program was considered a success, especially by previous standards for television outreach sponsored by 4-H. The series had a moderate impact on kids making better choices in what they ate, and provided 4-H with a sizable marketing, promotional and public relations boost. Thanks in part to the popularity of Mulligan Stew, 4-H membership was boosted to an all-time high in 1974, and the series continued to air in reruns on public television until 1981.
Sources: en.wikipedia.org
=== Visual effects === The companies that were in charge of creating the visual effects for the season were Pixomondo, Rocket Science VFX, MPC Episodic, Soho VFX, Ingenuity Studios, Rising Sun Pictures, Studio 8, and Outpost VFX. Stephan Fleet was in charge of being the VFX supervisor once again after working for the previous seasons. Fleet revealed that the season would have bigger visual effects than the previous seasons but will keep the characters and story that was created by the creators of the series. Laz Alonso revealed that the season used over three times the amount of blood more than the previous season: "I'll put it to you this way. I was talking to the head makeup artist and she's in charge of ordering the blood — that's one of her many jobs. She told me that all of Season 2 ... When you talk about bulk, I don't think they used over a gallon of blood in Season 2, believe it or not. Season 3, we're already at three and a half gallons of blood. So that should give you a little indication of where it's going." Rocket Science VFX was in charge of the creation of series fire explosions, Soldier Boy's powers, and the body and head explosions, by taking a 3D environment work since the creation of the effects would be heavier. To achieve Soldier Boy's powers, the crew looked for real radioactive blast to have them combined with FX fire and make blast simulations. Rising Sun Pictures worked to get the effects of the destruction provoqued through the series and captured over 100 shots during the season.
Predators of cnidarians include: sea slugs, flatworms and comb jellies, which can incorporate nematocysts into their own bodies for self-defense (nematocysts used by cnidarian predators are referred to as kleptocnidae); starfish, notably the crown of thorns starfish, which can devastate corals; butterfly fish and parrot fish, which eat corals; and marine turtles, which eat jellyfish. Some sea anemones and jellyfish have a symbiotic relationship with some fish; for example clownfish live among the tentacles of sea anemones, and each partner protects the other against predators. Coral reefs form some of the world's most productive ecosystems. Common coral reef cnidarians include both anthozoans (hard corals, octocorals, anemones) and hydrozoans (fire corals, lace corals). The endosymbiotic algae of many cnidarian species are very effective primary producers, in other words converters of inorganic chemicals into organic ones that other organisms can use, and their coral hosts use these organic chemicals very efficiently. In addition, reefs provide complex and varied habitats that support a wide range of other organisms. Fringing reefs just below low-tide level also have a mutually beneficial relationship with mangrove forests at high-tide level and seagrass meadows in between: the reefs protect the mangroves and seagrass from strong currents and waves that would damage them or erode the sediments in which they are rooted, while the mangroves and seagrass protect the coral from large influxes of silt, fresh water and pollutants.
== Early life == Sheik was born on November 18, 1969, in Glen Ridge, New Jersey. He grew up in Montclair, New Jersey. Following his parents' divorce, he split time between his father's house in New Jersey and his mother's home in South Carolina. He was the half-brother of Broadway actress Kacie Sheik. Sheik's Juilliard-trained grandmother introduced him to the piano, and he later took up the electric guitar. By age 12, he was playing guitar with high school students in a cover band. After graduating from Phillips Academy, Andover in 1988, Sheik studied semiotics at Brown University; while at Brown, he played guitar in a band with fellow Brown student Lisa Loeb. Following his graduation from Brown in 1992, he moved to Los Angeles.
Plant hormones affect seed germination and dormancy by acting on different parts of the seed. Embryo dormancy is characterized by a high ABA:GA ratio, whereas the seed has high abscisic acid sensitivity and low GA sensitivity. In order to release the seed from this type of dormancy and initiate seed germination, an alteration in hormone biosynthesis and degradation toward a low ABA/GA ratio, along with a decrease in ABA sensitivity and an increase in GA sensitivity, must occur. ABA controls embryo dormancy, and GA embryo germination. Seed coat dormancy involves the mechanical restriction of the seed coat. This, along with a low embryo growth potential, effectively produces seed dormancy. GA releases this dormancy by increasing the embryo growth potential, and/or weakening the seed coat so the radical of the seedling can break through the seed coat. Different types of seed coats can be made up of living or dead cells, and both types can be influenced by hormones; those composed of living cells are acted upon after seed formation, whereas the seed coats composed of dead cells can be influenced by hormones during the formation of the seed coat. ABA affects testa or seed coat growth characteristics, including thickness, and effects the GA-mediated embryo growth potential. These conditions and effects occur during the formation of the seed, often in response to environmental conditions. Hormones also mediate endosperm dormancy: Endosperm in most seeds is composed of living tissue that can actively respond to hormones generated by the embryo.
The origin and first recorded use of the term megacap (or any of its various spellings), in relation to stock capitalization, is unclear. It dates back to at least 1997, if not earlier. The S&P 100 was launched on June 15, 1983. The Russell Top 200 Index was launched on September 1, 1992. The Fidelity Mega Cap Stock Fund's inception was on December 28, 1998. The Russell Top 50 Mega Cap Index was launched on January 1, 2005. Also in 2005, investment advisory executive Richard Imperiale noted that some investors were classifying "the top 10 percent of companies by market cap" into a mega cap segment of the stock market. In 2009, the third edition of Stock Investing For Dummies defined mega caps (and ultra caps) as companies with market caps over $50 billion. Subsequent editions used that definition until 2020, when the sixth edition redefined them as having market caps over $200 billion. The 2023 version, retitled Investing in Stocks For Dummies, used the same definition as the sixth edition. The Morningstar US Mega Cap Index was established on March 31, 2011. In 2011, Investing Demystified defined mega-caps as companies with market caps of at least $25 billion, whereas in the same year, The Complete Idiot's Guide to Stock Investing defined them as having market caps at least $50 billion. That's equivalent to $34 billion and $69 billion, respectively, in 2024 using GDP deflator adjustment. In 2014, Asset Allocation Demystified stated that a typical mega cap company had a market cap of over $50 billion. The S&P 500 Top 50 Index was launched on November 30, 2015.
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。