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At least 127 records · Page 7Linked to original sources
PubMed1983

Congenital tuftsin deficiency.

The serum tuftsin activity in four different pediatric groups has been studied: (a) 20 premature infants, (b) 20 full-term infants, (c) 20 normal children (controls), and (d) 5 patients with recurrent and severe infections of the respiratory system, skin, and lymph nodes. The normal children as well as the premature and full-term infants had normal tuftsin activity. Tuftsin activity in the serum of the 5 patients in group (d) was absent. Cellular and humoral immunity in these patients was normal. All patients have been shown to have a mutant peptide that is strongly inhibitory to the normal tetrapeptide tuftsin. The clinical response of these patients to gamma-globulin was excellent.

Adolescent↗
PubMed1994

Tuftsin-bearing liposomes as rifampin vehicles in treatment of tuberculosis in mice.

The antitubercular activity of rifampin was considerably increased when it was encapsulated in egg phosphatidylcholine liposomes. A further increase in the activity was observed when the macrophage activator tetrapeptide tuftsin was grafted on the surface of the drug-loaded liposomes. Intermittent treatments (twice weekly) with these preparations were significantly more effective than the continuous treatments. Rifampin delivered twice weekly for 2 weeks in tuftsin-bearing liposomes was at least 2,000 times more effective than the free drug in lowering the load of lung bacilli in infected animals. However, pretreatment with drug-free tuftsin-bearing liposomes did not render the pretreated animals resistant to the Mycobacterium tuberculosis infections, neither did it appreciably increase the chemotherapeutic efficacy of the liposomized rifampin. These results clearly demonstrate that liposome targeting to macrophages could considerably increase the antitubercular activity of liposomized drugs such as rifampin. Also, it shows that immunoprophylactic treatment with macrophage activators such as tuftsin does not afford any advantage in treatment of tuberculosis infections, presumably because of inactivation of the primed macrophages by the mycobacterial sulfatides.

Amino Acid Sequence↗
PubMed1994

The macrophage-activating tetrapeptide tuftsin induces nitric oxide synthesis and stimulates murine macrophages to kill Leishmania parasites in vitro.

The macrophage-activating tetrapeptide tuftsin was able to activate, in a dose-dependent manner, murine macrophages to express nitric oxide (NO) synthase and to produce NO. Tuftsin required lipopolysaccharides for the optimal induction of NO production and synergized with gamma interferon in the induction of NO synthesis. Tuftsin-dependent NO production was sensitive to inhibition by dexamethasone and the NO synthase specific inhibitor LGN-monomethylarginine (L-NMMA). Murine peritoneal macrophages activated by tuftsin were able to kill the amastigotes of the intracellular protozoan parasite Leishmania major in vitro.

Animals↗
PubMed1991

[Macrophage activation by synthetic peptides. III. Changes in the membrane potential, Ca2+ content and the regulatory decrease of macrophage volume under the action of tuftsin and its antagonist].

With the use of oxonol voltage-sensitive fluorescent dye it has been shown that the stimulation of macrophages (MP) with tuftsin results in a two-phase change in membrane potential: depolarization followed by hyperpolarization of plasma membrane. The pattern of changes in membrane potential depends on Na+ concentration in the medium and is disturbed with binding of cytoplasmic Ca2+. Fluorescent signal obtained from MP loaded with Ca(2+)-activated photoprotein obelin points to a significant increase in the concentration of cytoplasmic Ca2+ under the influence of tuftsin on cells: the source for Ca2+ being the medium. The rate of regulatory voltage decrease in MP increases under the influence of tuftsin: the effect of this peptide being similar to that of calcium ionophore. All these findings taken together enable us to suggest a phenomenological scheme of transmembrane ion signals arising during stimulation of MP with tuftsin: the receptor-mediated calcium channel provides a rise in cytoplasmic Ca2+ which opens non-selective cation channels for Na+ ions to activate eventually Ca(2+)-dependent K(+)-transport.

Animals↗
PubMed1988

Effect of the N-terminal tetrapeptide of substance P SP (1-4) and tuftsin on the pre- and postsynaptic transmitter outflow in rat adrenal gland slices.

Two structurally related tetrapeptides, the N-terminal tetrapeptide of substance P SP(1-4) and tuftsin, exerted some similarities in modifying immune reactions and normalizing stress-induced disorders in the catecholamine system of adrenals. This paper presents results about the effects of tuftsin and SP(1-4) on the cholinergic-adrenergic interaction in rat adrenal gland slices. Both, tuftsin and SP(1-4) inhibited the nicotine-evoked [3H]noradrenaline outflow (postsynaptic effect), but the effect of SP(1-4) was more pronounced. SP(1-4) also inhibited the electrically stimulated [3H]ACh outflow (presynaptic effect), whereas tuftsin did not affect the ACh outflow. It is suggested that the regulation of the cholinergic-adrenergic interaction in adrenals is mediated by specific receptors, which are different on the pre- and postsynaptic side.

Acetylcholine↗
PubMed1985

Effect of tuftsin on in vivo development of 3-methylcholanthrene-induced primary fibrosarcoma and Lewis lung carcinoma in mice.

The effect of tuftsin therapy on tumor development was examined in a murine primary fibrosarcoma and the Lewis lung carcinoma systems. Following im injection of 3-methylcholanthrene (CAS: 56-49-5) on day 0, C57BL/10ScSn mice were treated weekly with 3 ip tuftsin injections beginning on day 1 or day 60. Similar patterns of tumor development were observed regardless of whether tuftsin therapy was immediate or delayed. Only modest differences in experimental and control tumor incidences were found upon termination of studies; however, treated animals developed significantly fewer tumors than controls early during the observation periods. Thus mean tumor latent periods varied significantly when therapy began on day 1 (103.6 days in controls vs. 119.1 in treated mice; P = .02) or 2 months later (104.6 days in controls vs. 115.3 in treated mice; P = .01). One day subsequent to intra-footpad implantation of 10(5) Lewis lung carcinoma cells, C57BL/6 mice received at least 10 iv injections of tuftsin and were compared with controls for variations in survival or lung tumor development. The mean survival time in treated mice, 41.2 days, differed sharply from that (30.1 days) in controls (P = .00001). Similar groups of mice varied significantly in mean metastatic lung colony counts when examined on day 30; there were 15.1 colonies in controls and 8.0 in experimental animals (P = .03).

Animals↗
PubMed1984

[Tuftsin].

Literature review. The tetrapeptide tuftsin (Thr-Lys-Pro-Arg) is cleaved off the carrier IgG molecule enzymatically and stimulates the phagocytic and bactericidal activity of polymorphonuclear leucocytes and macrophages. The action of tuftsin is mediated by specific receptor sites on the surface of these cells. Its antitumor activity has been shown in vitro as well as in vivo. The influence of tuftsin on the major metabolic processes of the cell (hexosemonophosphate shunt; cAMP/cGMP; Ca++-distribution; redox reactions) is the basis of its mode of action.--The feature of tuftsin and its low toxicity make it a useful agent for immunotherapy.

Animals↗
PubMedDate not supplied

Antitumor activity of tuftsin on murine melanoma in vivo.

The effect of tuftsin on malignant melanoma was studied in vivo using a murine model system. It was found that tuftsin was capable of significantly reducing the number of tumor colonies appearing in the lungs of mice following iv administration of tumor cells. Although only a limited number of concentrations of tuftsin were used in our preliminary studies, it appears that tuftsin possesses antitumor activity over a wide range of doses.

Animals↗
PubMed1997

Release of reactive nitrogen intermediates from the peripheral blood-derived monocytes/macrophages of leprosy patients stimulated in vitro by tuftsin.

The production of reactive nitrogen intermediates (RNI) by macrophages is critical to host defence, particularly for exerting the bactericidal and tumoricidal properties. Nitric oxide (NO) were measured in the peripheral blood-derived monocytes/macrophages of normal and leprosy patients (BT/TT and BL/LL) in the presence and absence of 'tuftsin' as a function of in vitro culture age (on 1, 3, 7 days). Macrophages from both groups of leprosy patients were able to produce NO during the unstimulated state but only BL/LL macrophages could be activated by tuftsin to produce significantly high levels of NO. This increase was highest on day 1, then gradually decreased with in vitro culture age. Surprisingly, tuftsin was unable to enhance the NO production in normal macrophages above the basal level. Further, normal and BT/TT macrophages had only Cu-Zn derived superoxide dismutase (SOD) activity whereas BL/LL cultures has Cu-Zn and Mn derived SOD activity. These studies indicate that in BL/LL cultures: a, apart from tuftsin, some additional signal is required to activate nitric oxide synthase (NOS) gene for NO production; and b, Mn-SOD produced by Mycobacterium leprae is playing a defensive role against toxic-free radicals. The final outcome of this mechanism is the survival of M. leprae inside the macrophages.

Cells, Cultured↗
PubMed2004

Synthesis, conformation, and immunoreactivity of new carrier molecules based on repeated tuftsin-like sequence.

Sequential oligopeptides based on a pentapeptide (TKPKG) derived from tuftsin with different lengths were synthesized by stepwise solid phase methodology. These highly soluble oligomers were nontoxic on mouse spleen cells, and other biological data suggested that tuftsin-like properties were also presented. The (TKPKG)n (n=2,4,6,8) oligopeptides were not immunogenic; however, they increased sheep red blood cells (SRBC) antigen specific antibody response in mice, demonstrating their immunostimulatory effect. Chemotactic activity was also found on J774 monocyte cells, while MRC5 fibroblasts were chemotactically nonresponders to the tested forms of tuftsin. These oligomers showed unordered and flexible structure by CD measurements, confirmed by computer modeling studies indicating also a fairly good accessibility of the epsilon-amino group of each lysine residue. Data suggest that these new oligotuftsin derivatives can be considered as promising carriers for synthetic vaccine.

Amino Acid Sequence↗
PubMed1983

Potentiation of the defective monocyte chemotaxis in Hodgkin's disease by in vitro tuftsin treatment.

In vitro pre-incubation of monocytes derived from patients with Hodgkin's disease with tuftsin (50 micrograms/ml) significantly restored the deficient chemotactic responsiveness of these cells to the complement-derived factor C5a, as demonstrated by a monocyte migration assay based on the Boyden technique. Potentiation of the chemotactic responsiveness of monocytes was most significant after elective splenectomy. The results indicate that the specific receptors required for tuftsin activities may be available on the monocyte membranes in Hodgkin's disease. Since tuftsin is a natural, non-immunogenic tetrapeptide that can also be produced synthetically, it may provide a new therapeutic approach in Hodgkin's disease to at least partial restoration of the defective cellular immunity.

Adult↗
PubMed1987

Tuftsin induced tumor necrosis activity.

Tuftsin induced tumor necrosis activity was investigated. The activity was found in mice serum several days after i.p. injection of tuftsin. Further experiments with adhering peritoneal and spleen cells indicated that macrophages were the source of the observed activity. The same effect was observed when promyelocytic leukemia cells (HL60) were stimulated with different concentrations of the peptide. These showed yet another possible mechanism for tuftsin antineoplastic activity.

Animals↗
PubMed1986

Interactions of tuftsin with bovine serum albumin.

Interactions of tuftsin (Thr-Lys-Pro-Arg) with bovine serum albumin (BSA) were analysed by fluorescence spectroscopy and circular dichroism. The data show that tuftsin interacts weakly with BSA, but this interaction is considerably enhanced by introducing an apolar substituent at the C-terminus of the tetrapeptide. It is suggested that strong binding of tuftsin to albumin in blood may enhance its macrophage-stimulating activity in vivo.

Animals↗
PubMed1986

Protection of mice against Plasmodium berghei infection by a tuftsin derivative.

In Plasmodium berghei infections, the mortality rate and parasitaemias were significantly reduced and the mean survival time was considerably enhanced by pretreating the animals with a tuftsin derivative, Thr-Lys-Pro-ARg-NH-(CH2)2-NHCOC15H31. This effect of the modified tuftsin was further increased upon its incorporation in the liposome bilayer. These results indicate that tuftsin and its derivatives may prove useful in enhancing nonspecific host resistance against protozoan infections.

Animals↗
PubMed1989

Drug targeting in Leishmania donovani infections using tuftsin-bearing liposomes as drug vehicles.

The efficacy of sodium stibogluconate against Leishmania donovani infections was markedly enhanced by encapsulating this drug in tuftsin-bearing liposomes. Also, pretreatment of the animals with these liposomes (free of drug) rendered them resistant to this infection, possibly by activating the host's macrophages. These results demonstrate that tuftsin-bearing liposomes besides delivering the drug to the target cells could also enhance the nonspecific resistance against infections, thus offering an additional advantage over the use of tuftsin-free liposomes as drug carriers in leishmania therapy.

Adjuvants, Immunologic↗
PubMed1991

Bovine probursin tetradecapeptide contains amino acid sequence from somatostatin, tuftsin and bursin.

The B cell differentiating tripeptide bursin (lysyl-histidyl-glycyl-amide) is found in avian and mammalian bone marrow and in epithelial cells of the avian bursa of Fabricius and mammalian intrahepatic bile ducts. We now report the structure of probursin (Phe-Phe-Trp-Lys-Thr-Lys-Pro-Arg-Lys-His-Gly-Gly-Arg-Arg) isolated from bovine bone marrow and liver. Amino acids 1-5 correspond to the active site of somatostatin, 5-8 to tuftsin and 9-11 to bursin. Intact probursin has the biological activity of both somatostatin and bursin, and known enzyme cleavages could release free tuftsin, although intact probursin has low tuftsin activity. Probursin and its component peptides could regulate other bone marrow functions in addition to B cell differentiation, and, in mammals, could also regulate the function of hepatocytes and Kupffer cells after transport to the hepatic sinusoids via a local portal system involving the peribiliary capillary plexus.

Amino Acid Sequence↗
PubMedDate not supplied

Synthetic peptides from C-reactive protein containing tuftsin-related sequences.

Peptides containing Lys-Pro-Arg or Thr-Lys-Arg segments corresponding to various regions of human C-reactive protein were synthesized. The peptides prepared were composed of amino acid residues, 37-58, 51-58, 173-187 and 181-187 of C-reactive protein. The relationship between C-reactive protein, its synthetic fragments and tuftsin (Thr-Lys-Pro-Arg) was investigated in binding studies, enhancement of phagocytosis and change in cyclic nucleotide levels of mouse macrophages. The peptides AA 51-58 and 181-187 did enhance macrophage phagocytosis capacity to a similar extent to that of tuftsin. They showed however only negligible binding to the cells. The effect of C-reactive protein and the synthetic peptides on metabolic activity of neutrophils was also investigated. It was shown that the peptides inhibited to some degree superoxide production, lysozyme release and Vitamin B12 binding protein release from neutrophils in the absence and presence of the stimulants, PMA or Con A. Comparable activity with tuftsin was not found.

Amino Acid Sequence↗
PubMed2006

Immunomodulatory properties of new conjugates of muramyl dipeptide and nor-muramyl dipeptide with retro-tuftsin (Arg-Pro-Lys-Thr-OMe).

Six new conjugates of muramyl dipeptide and nor-muramyl dipeptide with retro-tuftsin were synthesised at Gdansk University of Technology. All compounds were investigated at Medical University of Gdansk. Their immunomodulatory properties were assessed using in vitro cultures of human subpopulations of white blood cells (peripheral blood mononuclear cells, peripheral blood lymphocytes, monocytes). We examined the viability of blood cells incubated with examined conjugates, as well as their ability to stimulate secretion of cytokines (TNFalpha--tumour necrosis factor alpha, IL6--interleukin 6) and cytotoxic activity of NK (Natural Killer) cells. Complementation in biological activity of muramyl dipeptide (MDP) and tuftsin in conjugates proved to be beneficial in the field of immunoadjuvanticity. Our investigations proved that new conjugates acquired features that native immunomodulators did not reveal separately. In examined compound, the part responsible for inducing cytotoxic activity of NK cells was the tuftsin part of the conjugates. MDP in conjugates was responsible for compound-induced synthesis of TNFalpha. The results of our study imply usefulness of the examine compounds (mainly A and B), as potential therapeutic agents.

Acetylmuramyl-Alanyl-Isoglutamine↗