This is a working overview of immune modulation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-15. Anything still debated is marked as such rather than presented as settled.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
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.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
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.
| 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 |
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.
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.
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.
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.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
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== Diagnostic use == S100B is secreted by astrocytes or can spill from injured cells and enter the extracellular space or bloodstream. Serum levels of S100B increase in patients during the acute phase of brain damage. Over the last decade, S100B has emerged as a candidate peripheral biomarker of blood–brain barrier (BBB) permeability and CNS injury. Elevated S100B levels accurately reflect the presence of neuropathological conditions including traumatic head injury or neurodegenerative diseases. Normal S100B levels reliably exclude major CNS pathology. Its potential clinical use in the therapeutic decision making process is substantiated by a vast body of literature validating variations in serum 100B levels with standard modalities for prognosticating the extent of CNS damage: alterations in neuroimaging, cerebrospinal pressure, and other brain molecular markers (neuron specific enolase and glial fibrillary acidic protein). However, more importantly, S100B levels have been reported to rise prior to any detectable changes in intracerebral pressure, neuroimaging, and neurological examination findings. Thus, the major advantage of using S100B is that elevations in serum or CSF levels provide a sensitive measure for determining CNS injury at the molecular level before gross changes develop, enabling timely delivery of crucial medical intervention before irreversible damage occurs. S100B serum levels are elevated before seizures suggesting that BBB leakage may be an early event in seizure development.
=== Terpolymers === Terpolymers of PVDF are the most promising one in terms of electromechanically induced strain. The most commonly used PVDF-based terpolymers are P(VDF-TrFE-CTFE) and P(VDF-TrFE-CFE). This relaxor-based ferroelectric terpolymer is produced by random incorporation of the bulky third monomer (chlorotrifluoroethylene, CTFE) into the polymer chain of P(VDF-TrFE) copolymer (which is ferroelectric in nature). This random incorporation of CTFE in P(VDF-TrFE) copolymer disrupts the long-range ordering of the ferroelectric polar phase, resulting in the formation of nano-polar domains. When an electric field is applied, the disordered nano-polar domains change their conformation to all-trans conformation, which leads to large electrostrictive strain and a high room-temperature dielectric constant of ~50.
=== Extracellular signalling and neurotransmission === Cells secrete ATP to communicate with other cells in a process called purinergic signalling. ATP serves as a neurotransmitter in many parts of the nervous system, modulates ciliary beating, affects vascular oxygen supply etc. ATP is either secreted directly across the cell membrane through channel proteins or is pumped into vesicles which then fuse with the membrane. Cells detect ATP using the purinergic receptor proteins P2X and P2Y. ATP has been shown to be a critically important signalling molecule for microglia - neuron interactions in the adult brain, as well as during brain development. Furthermore, tissue-injury induced ATP-signalling is a major factor in rapid microglial phenotype changes.
==== MeSH D08.811.074 – dna repair enzymes ==== MeSH D08.811.074.124 – deoxyribodipyrimidine photo-lyase MeSH D08.811.074.249 – dna glycosylases MeSH D08.811.074.249.500 – DNA-formamidopyrimidine glycosylase MeSH D08.811.074.249.750 – thymine dna glycosylase MeSH D08.811.074.249.875 – uracil-dna glycosidase MeSH D08.811.074.500 – dna ligases MeSH D08.811.074.750 – DNA-(apurinic or apyrimidinic site) lyase MeSH D08.811.074.781 – muts dna mismatch-binding protein MeSH D08.811.074.812 – muts homolog 2 protein MeSH D08.811.074.875 – polynucleotide 5'-hydroxyl-kinase
Sources: en.wikipedia.org
=== Cryo-EM Facility === The cryo-EM facility at the Life Sciences Institute offers a wide range of advanced microscopes and technologies for cryo-electron microscopy, cryo-electron tomography, and correlative light and electron microscopy (CLEM).
One-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights, and LED-based Christmas lights. Because of their long life, fast switching times, and visibility in broad daylight due to their high output and focus, LEDs have been used in automotive brake lights and turn signals. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, about 200 milliseconds faster than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED appear if the eyes quickly scan across the array. White LED headlamps are beginning to appear. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors. Due to the relative cheapness of low output LEDs, they are also used in many temporary uses such as glowsticks and throwies. Artists have also used LEDs for LED art.
Thus, a high ratio of [NADH] to [NAD+] or a high ratio of [ADP] [Pi] to [ATP] imply a high amount of reduced cytochrome c and a high level of cytochrome c oxidase activity. An additional level of regulation is introduced by the transport rates of ATP and NADH between the mitochondrial matrix and the cytoplasm.
===== MeSH D08.811.277.352 – esterases (EC 3.1) ===== MeSH D08.811.277.352.100 – carboxylic-ester hydrolases MeSH D08.811.277.352.100.050 – acetylesterase MeSH D08.811.277.352.100.100 – carboxylesterase MeSH D08.811.277.352.100.150 – cholesterol esterase MeSH D08.811.277.352.100.170 – cholinesterases MeSH D08.811.277.352.100.170.176 – acetylcholinesterase MeSH D08.811.277.352.100.170.250 – butyrylcholinesterase MeSH D08.811.277.352.100.170.710 – pseudocholinesterase MeSH D08.811.277.352.100.220 – dehydroascorbatase MeSH D08.811.277.352.100.400 – lipase MeSH D08.811.277.352.100.400.745 – pancrelipase MeSH D08.811.277.352.100.430 – lipoprotein lipase MeSH D08.811.277.352.100.500 – monoacylglycerol lipases MeSH D08.811.277.352.100.550 – naphthol as d esterase MeSH D08.811.277.352.100.680 – phospholipases MeSH D08.811.277.352.100.680.510 – lysophospholipase MeSH D08.811.277.352.100.680.750 – phospholipases a MeSH D08.811.277.352.100.680.750.500 – 1-alkyl-2-acetylglycerophosphocholine esterase MeSH D08.811.277.352.335 – deoxyribonucleases MeSH D08.811.277.352.335.350 – endodeoxyribonucleases MeSH D08.811.277.352.335.350.025 – aspergillus nuclease s1 MeSH D08.811.277.352.335.350.137 – deoxyribonuclease (pyrimidine dimer) MeSH D08.811.277.352.335.350.250 – deoxyribonuclease i MeSH D08.811.277.352.335.350.250.900 – streptodornase and streptokinase MeSH D08.811.277.352.335.350.275 – deoxyribonuclease iv (phage t4-induced) MeSH D08.811.277.352.335.350.300 – dna restriction enzymes MeSH D08.811.277.352.335.350.300.250 – deoxyribonucleases, type i site-specific MeSH D08.811.277.352.335.350.300.260 – deoxyribonucleases, type ii site-specific MeSH D08.811.277.352.335.350.300.260.240 – deoxyribonuclease bamhi MeSH D08.811.277.352.335.350.300.260.250 – deoxyribonuclease ecori MeSH D08.811.277.352.335.350.300.260.260 – deoxyribonuclease hindiii MeSH D08.811.277.352.335.350.300.260.300 – deoxyribonuclease hpaii MeSH D08.811.277.352.335.350.300.270 – deoxyribonucleases, type iii site-specific MeSH D08.811.277.352.335.350.400 – holliday junction resolvases MeSH D08.811.277.352.335.350.500 – micrococcal nuclease MeSH D08.811.277.352.335.375 – exodeoxyribonucleases MeSH D08.811.277.352.335.375.750 – exodeoxyribonuclease V MeSH D08.811.277.352.355 – endonucleases MeSH D08.811.277.352.355.325 – endodeoxyribonucleases MeSH D08.811.277.352.355.325.025 – aspergillus nuclease s1 MeSH D08.811.277.352.355.325.300 – dna restriction enzymes MeSH D08.811.277.352.355.325.300.250 – deoxyribonucleases, type i site-specific MeSH D08.811.277.352.355.325.300.260 – deoxyribonucleases, type ii site-specific MeSH D08.811.277.352.355.325.300.260.240 – deoxyribonuclease bamhi MeSH D08.811.277.352.355.325.300.260.250 – deoxyribonuclease ecori MeSH D08.811.277.352.355.325.300.260.260 – deoxyribonuclease hindiii MeSH D08.811.277.352.355.325.300.260.300 – deoxyribonuclease hpaii MeSH D08.811.277.352.355.325.300.270 – deoxyribonucleases, type iii site-specific MeSH D08.811.277.352.355.325.350 – flap endonucleases MeSH D08.811.277.352.355.325.400 – holliday junction resolvases MeSH D08.811.277.352.355.325.500 – micrococcal nuclease MeSH D08.811.277.352.355.350 – endoribonucleases MeSH D08.811.277.352.355.350.025 – aspergillus nuclease s1 MeSH D08.811.277.352.355.350.500 – micrococcal nuclease MeSH D08.811.277.352.355.350.700 – ribonuclease h, calf thymus MeSH D08.811.277.352.355.350.715 – ribonuclease, pancreatic MeSH D08.811.277.352.355.350.725 – ribonuclease t1 MeSH D08.811.277.352.355.350.810 – RNA-induced silencing complex MeSH D08.811.277.352.365 – exonucleases MeSH D08.811.277.352.365.290 – exodeoxyribonucleases MeSH D08.811.277.352.365.300 – exoribonucleases MeSH D08.811.277.352.640 – phosphoric diester hydrolases MeSH D08.811.277.352.640.050 – annexin A3 MeSH D08.811.277.352.640.125 – 3',5'-cyclic-GMP phosphodiesterase MeSH D08.811.277.352.640.150 – 3',5'-cyclic-nucleotide phosphodiesterase MeSH D08.811.277.352.640.160 – 2',3'-cyclic-nucleotide phosphodiesterases MeSH D08.811.277.352.640.295 – glycerophosphoinositol inositolphosphodiesterase MeSH D08.811.277.352.640.430 – phosphodiesterase i MeSH D08.811.277.352.640.700 – phospholipases MeSH D08.811.277.352.640.700.700 – phospholipase c MeSH D08.811.277.352.640.700.700.500 – phosphatidylinositol diacylglycerol-lyase MeSH D08.811.277.352.640.700.700.750 – phospholipase c gamma MeSH D08.811.277.352.640.700.710 – phospholipase d MeSH D08.811.277.352.640.750 – sphingomyelin phosphodiesterase MeSH D08.811.277.352.650 – phosphoric monoester hydrolases MeSH D08.811.277.352.650.025 – acid phosphatase MeSH D08.811.277.352.650.035 – alkaline phosphatase MeSH D08.811.277.352.650.200 – fructose-bisphosphatase MeSH D08.811.277.352.650.225 – glucose-6-phosphatase MeSH D08.811.277.352.650.300 – histidinol-phosphatase MeSH D08.811.277.352.650.575 – 4-nitrophenylphosphatase MeSH D08.811.277.352.650.600 – nucleotidases MeSH D08.811.277.352.650.600.600 – 5'-nucleotidase MeSH D08.811.277.352.650.620 – phosphatidate phosphatase MeSH D08.811.277.352.650.622 – phosphofructokinase-2 MeSH D08.811.277.352.650.625 – phosphoprotein phosphatase MeSH D08.811.277.352.650.625.150 – calcineurin MeSH D08.811.277.352.650.625.300 – glycogen-synthase-d phosphatase MeSH D08.811.277.352.650.625.475 – myosin light-chain phosphatase MeSH D08.811.277.352.650.625.650 – phosphorylase phosphatase MeSH D08.811.277.352.650.625.700 – protein-tyrosine-phosphatase MeSH D08.811.277.352.650.625.700.150 – antigens, cd45 MeSH D08.811.277.352.650.625.700.200 – cdc25 phosphatase MeSH D08.811.277.352.650.625.725 – pyruvate dehydrogenase (lipoamide)-phosphatase MeSH D08.811.277.352.650.700 – 6-phytase MeSH D08.811.277.352.650.850 – pten phosphohydrolase MeSH D08.811.277.352.660 – phosphoric triester hydrolases MeSH D08.811.277.352.660.500 – aryldialkylphosphatase MeSH D08.811.277.352.700 – ribonucleases MeSH D08.811.277.352.700.350 – endoribonucleases MeSH D08.811.277.352.700.350.025 – aspergillus nuclease s1 MeSH D08.811.277.352.700.350.262 – eosinophil cationic protein MeSH D08.811.277.352.700.350.381 – eosinophil-derived neurotoxin MeSH D08.811.277.352.700.350.500 – micrococcal nuclease MeSH D08.811.277.352.700.350.700 – ribonuclease h, calf thymus MeSH D08.811.277.352.700.350.707 – ribonuclease iii MeSH D08.811.277.352.700.350.711 – ribonuclease p MeSH D08.811.277.352.700.350.715 – ribonuclease, pancreatic MeSH D08.811.277.352.700.350.725 – ribonuclease t1 MeSH D08.811.277.352.700.350.810 – RNA-induced silencing complex MeSH D08.811.277.352.700.375 – exoribonucleases MeSH D08.811.277.352.827 – sulfatases MeSH D08.811.277.352.827.070 – arylsulfatases MeSH D08.811.277.352.827.070.060 – n-acetylgalactosamine-4-sulfatase MeSH D08.811.277.352.827.070.250 – cerebroside-sulfatase MeSH D08.811.277.352.827.070.625 – steryl-sulfatase MeSH D08.811.277.352.827.180 – chondroitinases and chondroitin lyases MeSH D08.811.277.352.827.180.175 – chondroitinsulfatases MeSH D08.811.277.352.827.180.175.060 – n-acetylgalactosamine-4-sulfatase MeSH D08.811.277.352.827.180.175.275 – chondro-4-sulfatase MeSH D08.811.277.352.827.500 – iduronate sulfatase MeSH D08.811.277.352.897 – thiolester hydrolases MeSH D08.811.277.352.897.075 – acetyl-CoA hydrolase MeSH D08.811.277.352.897.700 – palmitoyl-coa hydrolase MeSH D08.811.277.352.897.850 – ubiquitin thiolesterase
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.
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.