Tuftsin stimulates thyrotropin secretion in rats.
Tuftsin acts at the hypothalamus level to stimulate thyrotropin-releasing hormone and thyrotropin secretion in rats.
Animals↗
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Modification of morphine withdrawal: effect of tuftsin, [Lys4]-tuftsinyltuftsin, tetrapeptide fragment (1-4) of substance P and its amide.
Withdrawal behavior in morphine-dependent rats precipitated by naloxone was attenuated after pretreatment with the tetrapeptide tuftsin and to some extent by its synthetic derivative [Lys4]-tuftsinyltuftsin. The tetrapeptide fragment (1-4) of Substance P was ineffective in suppressing morphine-withdrawal behavior, whereas its C-amide exerted only weak action. Possible involvement of an immunological mechanism is discussed.
Adjuvants, Immunologic↗
Solution conformation of tuftsin.
Conformation of chemically synthesized tetrapeptide tuftsin, an important immunomodulator, with the sequence Thr-Lys-Pro-Arg-OH has been studied in aqueous solution as well as in a number of organic solvents viz. trifluoroethanol (TFE), methanol and dioxane by circular dichroism (CD) spectroscopy which reveals preferential occurrence of mixture of random coil and beta-turns, that has already been predicted as bioactive conformation of this peptide.
Circular Dichroism↗
The immunomodulatory activity of tetra- and tripeptides of tuftsin-kentsin group.
It was found that tuftsin (Thr-Lys-Pro-Arg) and its tetrapeptide analogues with the same amino acid composition, but different sequences, demonstrate immunosuppressive activity for the humoral, but not (excepting the Thr-Lys-Arg-Pro tetrapeptide) for the cellular, immune response. The splitting of N-terminal residues from these tetrapeptides leads, however, to formation of tripeptides that are active in both humoral and cellular immune response tests. Thus, the biological degradation of peptides of the type investigated can seriously modulate their immunobiological activities. We also found that tetrapeptides Thr-Arg-Lys-Pro and Thr-Lys-Arg-Pro, as well as tripeptides Arg-Lys-Pro and Lys-Arg-Pro, distinctly differ in their immunomodulatory activities, although the structural differences consist in this case only in the displacement of two basic amino acid residues.
Amino Acid Sequence↗
Solution conformation of tuftsin.
Tuftsin, a natural linear tetrapeptide (Thr-Lys-Pro-Arg) of potential antitumor activity, has been studied in DMSO-d6 solution by 2D NMR spectroscopy. 1H and 13C spectra show the presence of two families of conformations characterized by a trans or cis Lys-Pro bond, respectively. The family of conformers containing the cis peptide bond is a mixture of extended structures as expected for a short linear peptide. On the contrary, the trans isomer appears to be a rigid, folded conformer, as indicated by crucial NOEs and by the exceptionally low temperature coefficient of Arg NH. Analysis of the solution data by means of energy calculations leads to a unique structure, characterized by a Lys-Pro inverse gamma-turn.
Amino Acid Sequence↗
Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress.
White laboratory male rats, inbred male C57BL/6 and Balb/c mice, and male Wistar rats, all previously divided on the basis of the type of emotional reactivity, were used to compare the effects of ten peptide compounds of the tuftsin family and Selank on the behavioral manifestations of emotional stress created by a conflict situation. Peptides were shown to have positive emotional effects and antistress actions. Individual physiologically significant effects were seen, due to the molecular structures of the study peptides and/or their degradation fragments. The results demonstrate the potential for the synthesis of peptide compounds with predictable directions of pharmacological actions and safe for wide use.
Adaptation, Psychological↗
A luminescent probe containing a tuftsin targeting vector coupled to a terbium complex.
Orthogonal protection strategies have been used to prepare a series of luminescent and MRI active lanthanide complexes containing a tuftsin targeting vector that are internalised by macrophage cells.
Chromatography, High Pressure Liquid↗
Tuftsin (an Ig-associated tetrapeptide) triggers the immunogenic function of macrophages: implications for activation of programmed cells.
The immunoglobulin heavy-chain-associated tetrapeptide, tuftsin (Thr-Lys-Pro-Arg), known for its phagocytosis-stimulating activity, was found to augment the antigen-specific, macrophage-dependent education of T lymphocytes. The investigation of stereospecific characteristics of the tetrapeptide, by use of structural analogs with different modifications, revealed strict structural requirements for eliciting the immunogenic activity of macrophages. It was found that the most important moiety for its activity is the dipeptide Pro-Arg. This finding is of interest in view of the appearance of this particular dipeptide in other bioregulatory peptides, including many of the peptide hormones. The significance of the appearance of a common structure in such molecules, which may act through specific receptors on different target cells, is discussed.
Amino Acid Sequence↗
Increased expression of endogenous xenotropic murine retrovirus by treatment with the tetrapeptides, tuftsin and kentsin.
Enhancement of endogenous xenotropic virus expression has been found upon treatment with tetrapeptides of a high-passage clone of Balb/c (K-Balb) mouse cells transformed with Kirsten sarcoma virus. Tuftsin (Thr-Lys-Pro-Arg) and kentsin (Thr-Pro-Arg-Lys) increased the expression of virus that was infectious for rat, but not mouse, cells in a concentration-dependent fashion. The enhancement of virus expression by the tetrapeptides was proportional to the spontaneous release of virus. The infectivity of the enhanced virus was neutralized by goat anti-RLV gp70 serum. Actinomycin D inhibited the induction of virus, suggesting that enhanced expression required de novo RNA synthesis. The effects observed using K-Balb cells offer an opportunity to study the many biological effects of these peptides in a fibroblast culture system.
Animals↗
Tuftsin analogs with D-amino acid residues.
The syntheses of nine tuftsin analogs containing D-amino acid residues are described. Their biological activity is discussed in terms of possible influence of the configurational change in definite position of the peptide chain on the preservation of beta-bend conformation of the tetrapeptide.
Amino Acids↗
Synthesis and biological investigations of new tuftsin analogs with elongated peptide chain.
In this paper the synthesis of the following elongated tuftsin analogs: Thr-Lys-Pro-Lys-Thr-Lys-Pro-Lys (I), Thr-Lys-Pro-Lys-Thr-Lys-Pro-Arg (II) and Ala-Lys-Thr-Lys-Pro-Arg-Glu-Gln (III) by the classical method is described. The compound II markedly inhibited the growth of murine sarcoma viruses (MSV).
Amino Acid Sequence↗
Synthesis of tritiated tuftsin and macrophage inhibitory tripeptide via acetylenic intermediates.
Acetylenic analogues of tuftsin (Thr-Dah-Pro-Arg) and of a macrophage inhibitory tripeptide (Thr-Dah-Pro) have been synthesized by conventional procedures in solution (Dah = 2,6-diamino-4-hexynoic acid). These acetylenic derivatives are intermediates for the preparation of structurally unmodified, tritiated peptides. Catalytic tritiation of Thr-Dah-Pro-Arg and of Thr-Dah-Pro has afforded the radioactive tetra- and tripeptides with specific activities of 11.4 Ci/mmol and 37 Ci/mmol, respectively.
Acetylene↗
Influence of the peptide chain length of new elongated tuftsin analogs on phagocytosis process.
In this paper the synthesis of the following elongated tuftsin analogs: Arg-Thr-Lys-Pro-Arg (1), Pro-Arg-Thr-Lys-Pro-Arg(II), Lys-Pro-Arg-Thr-Lys-Pro-Arg(III) and Thr-Lys-Pro-Arg-Thr-Lys-Pro-Arg(IV) by classical and solid-phase methods are described. The obtained peptides were tested for their biological activity: restoration of the phagocytosis of defected granulocytes from blood of children with acute lymphoblastic leukemia (ALL).
Child↗
[Hyp3]-tuftsin ([Hyp3]-TU) synthesis and biological activity.
[Hyp3]-tuftsin (Thr-Lys-Hyp-Arg) has been synthesized by the liquid-phase method. In biological investigations performed on rats antinociceptive and diuretic effects have been determined. It has been suggested that the presence of hydroxyl substituent in pyrrolidine ring of proline slightly modifies antinociceptive TU effect and is responsible for the increased diuretic [Hyp3]-TU activity.
Animals↗
Infrared spectroscopic investigations of tuftsin and its analogs.
The ability of tuftsin and its analogs to form folded intramolecularly hydrogen-bonded structures has been investigated by infrared spectroscopy. The appearance of beta-turns is documented for peptides containing proline in position 3 of the chain. Correlation of spectroscopic data with biological activity in the investigated series is attempted.
Hydrogen Bonding↗
New synthetic and natural tuftsin-related compounds and evaluation of their phagocytosis-stimulating activity.
The preparation of large amounts of tuftsin (50 g) as well as purification by preparative HPLC are presented. Synthesis of several analogues exhibiting significant phagocytosis-stimulating activity of human PMN are described and discussed. On the other hand, the synthesis of a natural human IgG decapeptide fragment 335-344 that could be liberated from the same carrier molecule is presented. This decapeptide fragment, Thr-Ile-Ser-Lys-Ala-Lys-Gly-Gln-Pro-Arg, showed interesting activity in stimulating phagocytosis of human polymorphonuclear leukocytes.
Amino Acid Sequence↗
Effect of liver transplantation on tuftsin activity and phagocytic activity of neutrophil granulocytes in patients with liver cirrhosis.
BACKGROUND: Tuftsin activity (TA) is reduced in cirrhosis. This contributes to the defective phagocytic activity (PA) of neutrophil granulocytes and is related to the impairment of splenic function. Orthotopic liver transplantation (OLT) cures cirrhosis and might restore TA. This study was aimed at determining if OLT restores TA and PA. METHODS: We measured in 9 cirrhotic patients, before and after successful OLT, TA by a bioassay and PA by chemiluminescence in which neutrophils of the patient were tested with both autologous (PA1) and pooled sera from healthy subjects (PA2). Splenic function was assayed by the pitted red cell count. RESULTS: Before OLT, TA was reduced in 7 patients, and PA1 in all the patients. Pitted cell count was elevated in all the patients. After OLT (median 39 months; range 21-49), TA improved in all cases [median: from 8% (5-16%) to 20% (9-22%), p < 0.008], normalizing in 5 out of the 7 patients with low values. PA1 improved in all the patients [from 102 cpm (65-128 cpm) to 235 cpm (78-280 cpm), p < 0.008], normalizing in 5. Pitted red count decreased in 7 patients and normalized in 3 [from 3.3% (2.1-6.0%) to 2.4% (1.4-2.8%), p < 0.021]. Platelet count [from 55 x 10(3) (30-100) to 185 x 10(3) (93-286), p < 0.008] and leucocyte count [from 3.60 x 10(3) (1.81-5.23) to 5.53 x 10(3) (3.31-6.71), p < 0.008] also improved. CONCLUSIONS: OLT improves TA and PA of cirrhotic patients. This effect is associated with an improvement of both functional hyposplenism and haematological hypersplenism. The restoration of natural defences against infections may mitigate the adverse effect of immunosuppressive treatment.
Female↗
Molecular basis of familial and acquired phagocytosis deficiency involving the tetrapeptide, thr-lys-pro-arg, tuftsin.
The biological activity and metabolism of the phagocytosis stimulating tetrapeptide (Thr-Lys-Pro-Arg) tuftsin, are discussed. Its effect is shown to be highly specific. It stimulates the phagocytic activity of the blood polymorphonuclear leukocyte. A unique familial deficiency of the tetrapeptide is described. In such patients, moderate to severe infections occur at high frequency. These are most pronounced in children. Biochemical and symptomatic evidence can readily be obtained in one or more children. At least one parent of either sex shows clinical signs or laboratory evidence of defective phagocytosis. Another type of deficiency results from removal of the spleen or from loss of specific function due to leukemic infiltration or embolism.
Adolescent↗