Thymosin fraction-5 (TF5), an array of small molecular weight peptides present in crude extracts of the adult bovine thymus, contains numerous constituents with demonstrable biological activity. Because TF5 generally enhances immune reactivity in a variety of settings, and additionally restricts proliferation of certain neoplasms, we examined the effects of TF5 on proliferative capacity in the human promyelocytic leukemia cell line HL-60. Vital dye-exclusion, oxidative metabolism of chromogenic dyes, and clonogenic growth profiles were monitored to assess rates of cellular proliferation; our results demonstrate that TF5 restricted HL-60 cell growth, an influence that exhibited comparable potency and efficacy among all three indices. This antiproliferative activity was labile, insofar as medium conditioned in HL-60 cells for 24 h became devoid of the initial growth-suppressive activity after 24-h culture when subsequently administered to naive cultures. Review of cytoarchitectural traits, chromatin staining by TUNEL, and fluorescent cytometric analyses demonstrated that TF5 failed to elicit apoptosis, however, suggesting that this material instead drove treated cells into growth arrest and an unanticipated cytostasis. Qualitatively similar responses were noted in the human monoblastic leukemia cell line U937. Partial purification of TF5 by FPLC yielded a component containing an antiproliferative activity associated with the approximately 1000-Da fraction. These results demonstrate that TF5 contains a sub-fraction possessing a growth-suppressive activity capable of restraining normal proliferation of human myeloid neoplasms via the apparent induction of true cytostasis.
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http://dx.doi.org/10.1016/j.intimp.2005.04.001 | DOI Listing |
Expert Opin Biol Ther
July 2018
a Friedrich-Alexander-University Erlangen-Nuremberg , Institute of Biochemistry, Erlangen , Germany.
Objectives: We reevaluated a lyophilized sample of thymosin fraction 5, stored for 37 years at room temperature, by high-resolution mass spectrometry in terms of stability and yet uncharacterized polypeptides that could be biological important substances.
Methods: A top-down proteomic platform based on high-performance liquid chromatography (HPLC) coupled to high-resolution LTQ-Orbitrap mass spectrometry (MS) was applied to molecular characterization of polypeptides present in thymosin fraction 5.
Results: We detected more than 100 monoisotopic masses corresponding to thymosin β4 and truncated forms of ubiquitin, prothymosin α, thymosin β4, and thymosin β9.
Vestn Ross Akad Med Nauk
February 2015
Aim: The objective of this project was to explore the influence of immunoactive drugs (tactivin, thymulin, and thymosin fraction 5) on the development of the passive avoidance conditioned reflex.
Materials And Methods: Two types of passive avoidance boxes were used--a regular two-chamber box and a modified three-chamber box, comprising a dark chamber in which rats were exposed to electrical shock, a safe dark chamber, and a light chamber in the center.
Results: The project has established that the memory trace persists longer under the influence of the immunoactive drugs in both models, which is consistent with the reference nootropic piracetam test results.
Cochrane Database Syst Rev
February 2011
Medizinische Klinik 5-Schwerpunkt Onkologie/Haematologie, Klinikum Nord, Prof.-Ernst-Nathan-Str. 1, Nuernberg, Germany, D-90419.
Background: Purified thymus extracts (pTE) and synthetic thymic peptides (sTP) are thought to enhance the immune system of cancer patients in order to fight the growth of tumour cells and to resist infections due to immunosuppression induced by the disease and antineoplastic therapy.
Objectives: To evaluate the effectiveness of pTE and sTP for the management of cancer.
Search Strategy: We searched CENTRAL (The Cochrane Library 2010, Issue 3), MEDLINE, EMBASE, AMED, BIOETHICSLINE, BIOSIS, CATLINE, CISCOM, HEALTHSTAR, HTA, SOMED and LILACS (to February 2010).
Cell Motil Cytoskeleton
October 2009
Department of Anatomy and Embryology, Ruhr-University, D-44780 Bochum, Germany.
The beta-thymosins are N-terminally acetylated peptides of about 5 kDa molecular mass and composed of about 40-44 amino acid residues. The first member of the family, thymosin beta4, was initially isolated from thymosin fraction 5, prepared in five steps from calf thymus. Thymosin beta4 was supposed to be specifically produced and released by the thymic gland and to possess hormonal activities modulating the immune response.
View Article and Find Full Text PDFAnn N Y Acad Sci
September 2007
Department of Chemistry, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4003, USA.
Thymosin fraction-5 (TF5) is a protein preparation of the bovine thymus. TF5 stimulates many assays of T cell-mediated immunity. We found that TF5 substantially suppressed proliferation of the rat C6 glioma and MMQ pituitary adenoma cell lines.
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