Explore studies of immune function.
Thymosin peptides both increase and decrease TdT activity depending on the maturation stage, indicating they regulate multiple phases of T-cell development.
Hu, S K; Low, T L; Goldstein, A L · Animal Study
Mice lost immune killing power as they aged. By 24 months (equivalent to roughly 70+ human years), their spleen cells were much weaker at destroying tumor cells compared to 1-month-old mice. Four thymic hormones were tested: FTS (serum thymic factor), TP5 (a fragment of thymopoietin), TM4 (a synthetic version of TP5), and thymosin fraction V. Each worked differently depending on the age of the mouse and the dose used. The most striking result: TM4 at a very low dose (1 nanogram) actually suppressed immune killing in young mice but significantly boosted it in 12- and 24-month-old mice. FTS and TP5 partially restored killing ability in old mice. Thymosin fraction V had modest and inconsistent effects.
Ghanta, V K; Noble, P J; Brown, M E; Cox, P J; Hiramoto, N S; Hiramoto, R N · Animal Study
Natural killer (NK) cells are immune cells that destroy virus-infected and cancer cells without needing prior training. Cyclophosphamide (CY), a chemotherapy drug, wiped out NK cell activity in mice. Interferon alone (30,000 units per mouse) strongly boosted NK cells in healthy mice. But in CY-suppressed mice, interferon by itself did nothing. The combination worked: thymosin alpha 1 (200 micrograms/kg) given daily for 4 days, followed by a single interferon injection 24 hours before testing, fully restored NK cell activity in the immunosuppressed mice. Thymosin alpha 1 also accelerated NK cell recovery in mice that received bone marrow transplants.
Favalli, C; Jezzi, T; Mastino, A; Rinaldi-Garaci, C; Riccardi, C; Garaci, E · Animal Study
The paper argued that certain molecules made by immune cells can send signals directly to the brain. The authors named these 'immunotransmitters,' a new term for molecules that carry information from the immune system to the central nervous system (CNS). Examples include thymosin alpha 1 and thymosin beta 4 (peptides from the thymus gland), as well as ACTH (a stress hormone), TSH (thyroid hormone), and beta-endorphin (a natural painkiller) produced by lymphocytes (white blood cells). The review presented evidence that thymosin peptides can alter the hypothalamic-pituitary-adrenal (HPA) axis, which is the brain's master hormone control system. They also appeared to affect the gonadal (reproductive hormone) axis.
Hall, N R; McGillis, J P; Spangelo, B L; Goldstein, A L · Review
Parathymosin alpha is a newly discovered peptide of about 105 amino acid residues, isolated from rat thymus tissue. The first 30 amino acids of its sequence showed 43% structural identity with thymosin alpha 1 and prothymosin alpha. The structural overlap did not include residues 2 through 9 of thymosin alpha 1. This explained why antibodies targeting that region of thymosin alpha 1 did not recognize parathymosin alpha. Functionally, parathymosin alpha appeared to regulate prothymosin alpha's ability to protect sensitive mice from Candida albicans (a common fungal infection). This suggests it acts as a modulator of immune protection rather than a direct immune booster.
Haritos, A A; Salvin, S B; Blacher, R; Stein, S; Horecker, B L · In Vitro
The patient had primary intestinal lymphangiectasia (a condition where lymph vessels in the gut leak fluid, protein, and immune cells). Biopsies confirmed the diagnosis in her intestines, lungs, and lymph nodes. Lymphocytes were literally leaking out through her gut, confirmed by finding them in her stool. Her thymus gland was essentially absent. A biopsy showed no thymic tissue. Blood tests showed very low or absent thymulin and thymosin alpha 1. She had a selective loss of T-cells, especially CD4+ helper T-cells. Daily thymosin fraction 5 treatment produced a brief clinical improvement. But switching to weekly injections could not sustain it. Lymphocyte numbers never increased during treatment. The authors concluded that when the body loses T-cells faster than it can replace them, even thymic hormones cannot keep up without a functioning thymus.
Sorensen, R U; Halpin, T C; Abramowsky, C R; Hornick, D L; Miller, K M; Naylor, P; Incefy, G S · Case Report
Normal thymosin alpha 1 levels were similar across all groups of women tested, regardless of their hormonal status. This peptide appears unaffected by estrogen. Thymosin beta 4 told a different story. Castrated women not receiving estrogen had reduced levels. Postmenopausal women on chronic estrogen therapy had even lower thymosin beta 4. Castrated women on estrogen also showed decreased levels. Normal women in the early follicular phase (low estrogen point of the menstrual cycle), women with premature ovarian failure, and postmenopausal women not on estrogen all had similar thymosin beta 4 levels. But the premature ovarian failure and postmenopausal groups showed wide variation, suggesting these are not uniform populations.
Suh, B Y; Naylor, P H; Goldstein, A L; Rebar, R W · Cross Sectional
Thymosin alpha 1 (Ta-1) had strikingly different effects depending on the mouse strain. In B10.D2 mice (resistant to autoimmune thyroiditis), Ta-1 treatment between the two antigen injections actually increased thyroid inflammation. In B10.Br mice (naturally susceptible), Ta-1 suppressed the disease. Timing mattered. Early treatment (first 2 weeks) suppressed disease in the susceptible strain but worsened it in the resistant strain. Later treatment (weeks 3-4) had similar patterns. Different doses affected different T-cell subsets. The 0.01 microgram dose lowered Lyt-2+3+ cells (a type of immune cell) in resistant mice. The 0.001 microgram dose raised Lyt-1+ cells in the same strain. Each dose shifted the immune balance differently, which explains the opposing disease outcomes.
Tomazic, V J; Novotny, E A; Ordonez, J V · Animal Study
Leukocyte migration inhibition (LMI), a measure of how well immune cells respond to signals, was impaired in 24 head and neck cancer patients compared to healthy people. Adding thymosin alpha 1 to the lab dish improved LMI in the cancer patients' cells. The improvement appeared independent of T-cell subset levels, meaning thymosin alpha 1 was enhancing the function of existing cells rather than changing which cells were present. An interesting secondary finding: patients whose LMI was still normal had lower levels of suppressor/cytotoxic T-cells than both healthy people and patients with impaired LMI. This suggests that suppressor cells may contribute to the immune dysfunction in these cancers.
Wolf, G T; Peterson, K A; Lovett, E J · In Vitro
Normal thymosin alpha 1 levels: 670 ± 163 pg/mL for males and 652 ± 162 pg/mL for females. Normal thymosin beta 4 levels: 974 ± 400 ng/mL for males and 889 ± 345 ng/mL for females. Note that beta 4 levels are about 1,000 times higher than alpha 1. In AIDS patients, 57% had elevated thymosin alpha 1 and 48% had elevated thymosin beta 4. But there was no correlation between the two peptides' levels in any group, including healthy controls. People with AIDS-related immune dysfunction (not full AIDS) showed a different pattern: 54% had elevated thymosin alpha 1 but only 15% had elevated thymosin beta 4. This suggests thymosin alpha 1 rises earlier in the disease process.
Naylor, P H; Friedman-Kien, A; Hersh, E; Erdos, M; Goldstein, A L · Cross Sectional
Thymosin fraction 5 (TF5), a mix of thymic peptides, significantly increased both the percentage of human lymphocytes expressing IL-2 receptors (IL-2R) and the density of receptors on each cell. This happened after the cells were stimulated with PHA (a plant protein that activates immune cells). Synthetic thymosin alpha 1 alone produced the same effect, identifying it as the active ingredient in TF5. The effect was direct. When researchers used cyclosporin A (a drug that blocks IL-2 production), TF5 still increased IL-2R expression. This means thymosin works by directly putting more receptors on cells, not by making more IL-2. More receptors led to stronger cell multiplication.
Sztein, M B; Serrate, S A; Goldstein, A L · In Vitro
IL-2 is a 133-amino acid protein (molecular weight 15,420 daltons) produced by activated T-cells. Its gene sits on chromosome 4. The IL-2 receptor is a 272-amino acid protein (55,000 daltons). IL-2 does not just make immune cells copy themselves. It moves cells from a resting state (G1) through to DNA synthesis (S phase). During this process, the proto-oncogene c-myb increases 6 to 7 times above normal levels. The most exciting clinical development: IL-2 could expand LAK cells (lymphokine-activated killer cells) and TIL (tumor-infiltrating lymphocytes) that attack cancer. Early human trials showed both therapeutic promise and significant toxicity. Thymosin fraction 5 and thymosin alpha 1 could modulate IL-2 receptor expression on human blood cells, potentially increasing the effectiveness of IL-2 therapy.
Fletcher, M; Goldstein, A L · Review
The percentage of E-rosettes (a marker of mature T-cells) was lower in 33 acutely malnourished children compared to mildly growth-retarded children from the same area. But there was considerable overlap between groups, meaning not every malnourished child had low T-cells. This differed from studies in other countries where all severely malnourished children showed uniformly depressed T-cell markers. The authors suggested that specific nutrient deficiencies, not malnutrition overall, may drive immune problems. Adding thymosin fraction 5 to the children's blood cells in lab dishes increased E-rosette formation in a dose-dependent manner. This means immature T-cell precursors were present in the blood and could be pushed toward maturity with thymic peptides.
Keusch, G T; Cruz, J R; Torun, B; Urrutia, J J; Smith, H; Goldstein, A L · Cross Sectional
The new enzyme immunoassay (EIA) for thymulin achieved a sensitivity of 32.5 ± 5 pg/mL (IC50) with a detection limit of 5 pg/mL. This was more sensitive than previously available radioimmunoassays. The test was highly specific. It did not cross-react with thymosin alpha 1, thymopoietin II, or TP5 (another thymic peptide). Both the zinc-bound (biologically active) and zinc-free forms of thymulin showed the same immunoreactivity. Mapping studies showed that the minimum peptide structure needed for detection was the C-terminal portion from lysine-3 to asparagine-9 (7 of the 9 amino acids).
Métreau, E; Pléau, J M; Dardenne, M; Bach, J F; Pradelles, P · In Vitro
Eight monoclonal antibodies against thymosin alpha 1 were produced from mice immunized with synthetic thymosin alpha 1. The antibodies were screened using both solid-phase ELISA and liquid-phase radioimmunoassay for maximum specificity. Using indirect immunofluorescence on perfused rat thymus tissue, thymosin alpha 1-containing cells were found primarily in the thymic medulla. This confirmed earlier studies that used less specific polyclonal antibodies. The monoclonal antibodies provide a standardized, unlimited supply of reagent compared to the variable polyclonal antisera used previously. They can be used for both in vitro and in vivo studies of thymosin alpha 1 location and function.
Oates, K K; Naylor, P H; Goldstein, A L · In Vitro
Thymosin alpha-1 and lymphokine-containing supernatants directly stimulated both basal and corticotropin-induced corticosterone secretion from adrenal cells.
Torres-Alemán, I; Rejas, M T; Barasoaín, I; Borrell, J; Guaza, C · In Vitro
Met-enkephalin, leu-enkephalin, dynorphin (1-13), DSLET (delta agonist), and DAGO (mu agonist) were tested on human NK cells from healthy donors after 18-hour incubation. The results were bidirectional: populations with low baseline NK activity showed enhancement. Populations with high baseline NK activity showed suppression. This immunoregulatory pattern was consistent across different opioid peptides. The effect was confirmed in a serum-free system with recombinant interferon-alpha, ruling out serum-factor interference. Naloxone displayed both antagonist properties (blocking opioid effects) and direct immunomodulatory effects. This suggested lymphocytes themselves may produce opioid peptides in culture, creating an autocrine signaling loop.
Oleson, D R; Johnson, D R · In Vitro
Amniotic fluid thymosin alpha 1 levels were remarkably higher than newborn serum levels and increased in a logarithmic pattern with fetal age (r = 0.838).
Welch, R A; Lee, H H; Sokol, R J; Mutchnick, M G · Cross Sectional
Rhinovirus infection triggered significant increases in thymosin alpha 1 (p < 0.001), thymosin beta 4 (p < 0.001), and multiple immune cell types by day 5 after inoculation.
Hsia, J; Sztein, M B; Naylor, P H; Simon, G L; Goldstein, A L; Hayden, F G · RCT
TF5 stimulated IL-1 alpha (not IL-1 beta) production from monocytes. The active component was a novel basic peptide, not thymosin alpha 1.
Hu, S K; Badamchian, M; Mitcho, Y L; Goldstein, A L · In Vitro
Beta-endorphin and dynorphin replicated melatonin's immunoenhancing and anti-stress effects, but with complementary roles: beta-endorphin for normal conditions, dynorphin for stress states. Effects were circadian and opioid-receptor-mediated.
Maestroni, G J; Conti, A · Animal Study
Milk proteins contain encrypted bioactive peptide sequences that are released during digestion, including opioid-like casomorphins, mineral-binding phosphopeptides, and immunostimulating peptides.
Meisel, H; Frister, H; Schlimme, E · Review
No opioid peptide or morphine, across a wide concentration range, affected superoxide formation in human neutrophils or HL-60 cells under defined experimental conditions.
Seifert, R; Burde, R; Schultz, G · In Vitro
Thymosin alpha 1 modulates an early event in T cell activation. A 30-minute preincubation is sufficient to prime both CD4+ and CD8+ T cells, but macrophage-derived IL-1 is required for the enhanced response.
Sztein, M B; Serrate, S A · In Vitro
Prothymosin alpha acts as an accessory signal for T cell activation. It requires macrophage-derived IL-1 for its effect and works through an IL-2-dependent pathway.
Cordero, O J; Sarandeses, C S; Nogueira, M · In Vitro
Both thymosin alpha 1 and thymosin beta 4 suppress gut lamina propria lymphocyte proliferation through a mechanism that may involve protein kinase C but not calcium flux or ornithine decarboxylase pathways.
Elitsur, Y; Mutchnick, M G; Sakr, W A; Luk, G D · In Vitro
Thymosin alpha 1 increases high-affinity IL-2 receptor expression with a bimodal dose-response pattern. This directly correlates with enhanced IL-2 production and is only effective during immune activation.
Leichtling, K D; Serrate, S A; Sztein, M B · In Vitro
Morphine has anti-inflammatory effects on granulocytes through both opioid receptor-dependent (aggregation, ATP) and independent (arachidonic acid metabolism) mechanisms. Natural opioid peptides do not share these effects.
Mazzone, A; Ricevuti, G; Pasotti, D; Fioravanti, A; Marcoli, M; Lecchini, S; Notario, A; Frigo, G M · In Vitro
Immune cells in inflamed tissue release opioid peptides that activate receptors on sensory nerve terminals, producing local pain relief. This represents a newly discovered neuroimmune analgesic pathway.
Stein, C; Hassan, A H; Przewłocki, R; Gramsch, C; Peter, K; Herz, A · Animal Study
Chronic low-dose PCB exposure increased serum complement and NK cell activity while altering other immune parameters in rhesus monkeys.
Tryphonas, H; Luster, M I; White, K L; Naylor, P H; Erdos, M R; Burleson, G R; Germolec, D; Hodgen, M; Hayward, S; Arnold, D L · Animal Study
Central TNF-alpha and IL-1-alpha both increased nociceptive thresholds. TNF-alpha decreased locomotion. Naloxone partially reversed TNF-alpha's analgesic effect.
Bianchi, M; Sacerdote, P; Ricciardi-Castagnoli, P; Mantegazza, P; Panerai, A E · Animal Study
Salmonella genes required for antimicrobial peptide resistance were also required for macrophage survival and mouse virulence. Mutants were sensitive to both insect and mammalian peptides.
Groisman, E A; Parra-Lopez, C; Salcedo, M; Lipps, C J; Heffron, F · Animal Study
Thymic hormones (thymosin alpha-1, thymulin, thymopoietin) decline with age alongside thymic involution, and their supplementation shows potential for partially restoring age-related immune deficits.
Hadden, J W; Malec, P H; Coto, J; Hadden, E M · Review
Dynorphin immunoreactivity detected in both inflammatory cells and cutaneous sensory nerve fibers in Freund's adjuvant-inflamed rat paw tissue.
Hassan, A H; Pzewłocki, R; Herz, A; Stein, C · Animal Study
All three opioid precursor mRNAs detected in inflamed tissue. Opioid peptides localized to immune cells. Local opioid blockade increased pain, proving functional significance.
Przewłocki, R; Hassan, A H; Lason, W; Epplen, C; Herz, A; Stein, C · Animal Study
Native opioid peptides did not affect PMN respiratory burst. Opioid peptides modified by activated oxygen species enhanced PMA-stimulated respiratory burst.
Slaoui-Hasnaoui, A; Guerin, M C; Le Doucen, C; Loubatiere, J; Torreilles, J · In Vitro
Thymosin alpha 1 fully restored cocaine-suppressed antibody responses. Thymopentin partially restored them. Effect confirmed at the individual splenocyte level.
Ravagnan, G; Falchetti, R; Lanzilli, G; Di Francesco, P; Gaziano, R; Favalli, C; Garaci, E · Animal Study
All three opioid peptides found in synovial immune cells. Intra-articular naloxone increased post-surgical knee pain, proving endogenous opioids provide functional local analgesia.
Stein, C; Hassan, A H; Lehrberger, K; Giefing, J; Yassouridis, A · Cross Sectional
Dynorphin-A enhanced macrophage tumoricidal activity under suboptimal activation conditions but not when fully activated.
Hagi, K; Uno, K; Inaba, K; Muramatsu, S · In Vitro
Thymosin alpha 1 demonstrated promising antiviral and immune-enhancing effects in early hepatitis B and C trials, suggesting it could complement or replace interferon.
Mutchnick, M G; Ehrinpreis, M N; Kinzie, J L; Peleman, R R · Review
IL-1 beta and CRF caused immune cells in inflamed tissue to release opioid peptides that produced local pain relief, blocked by naloxone and anti-opioid antibodies.
Schäfer, M; Carter, L; Stein, C · Animal Study
Met-enkephalin, dynorphin, and kappa agonist U50,488 suppressed IL-6-induced HIV-1 expression by over 40% in chronically infected monocyte cells.
Chao, C C; Gekker, G; Sheng, W S; Hu, S; Portoghese, P S; Peterson, P K · In Vitro
Dynorphin A dose-dependently enhanced macrophage phagocytosis through a naloxone-insensitive (non-opioid receptor) mechanism.
Ichinose, M; Asai, M; Sawada, M · In Vitro
Brucella species showed broad resistance to 14 antimicrobial peptides, with their outer membranes remaining intact and binding less antimicrobial peptide than susceptible bacteria.
Martínez de Tejada, G; Pizarro-Cerdá, J; Moreno, E; Moriyón, I · In Vitro
Cecropin B was the most potent antimicrobial peptide against B. pertussis, with cecropins generally outperforming magainins, defensins, and protamine.
Fernandez, R C; Weiss, A A · In Vitro
Antimicrobial peptide effectiveness against Brucella abortus depended significantly on bacterial surface structure, with rough mutants showing different susceptibility patterns than smooth strains.
Halling, S M · In Vitro
Conditioned enhancement of NK cell activity depends on mu-opioid receptor activation, with beta-endorphin and met-enkephalin as the key mediating peptides.
Hsueh, C M; Chen, S F; Huang, H J; Ghanta, V K; Hiramoto, R N · Animal Study
Chronic intracerebroventricular beta-endorphin infusion significantly enhanced in vivo NK cell cytotoxicity and altered splenic and peripheral blood lymphocyte phenotypes.
Jonsdottir, I H; Johansson, C; Asea, A; Hellstrand, K; Thorén, P; Hoffmann, P · Animal Study
Combination thymosin alpha-1 (1 mg twice weekly) and lymphoblastoid interferon was tested as a strategy to improve sustained response rates in chronic hepatitis C over interferon monotherapy.
Rasi, G; DiVirgilio, D; Mutchnick, M G; Colella, F; Sinibaldi-Vallebona, P; Pierimarchi, P; Valli, B; Garaci, E · RCT
All five tested opioid peptides enhanced both NK cell and macrophage/monocyte cytotoxic activity when administered by single IP injection in mice.
Kowalski, J · Animal Study