Thymopoietin Pentapeptide Research Articles

Increased antitumor activity of tumor-specific peptide modified thymopentin.

Thymopoietin pentapeptide (thymopentin, TP5), an immunomodulatory peptide, has been successfully used as an immune system enhancer for treating immune deficiency, cancer, and infectious diseases. However, poor penetration into tumors remains a key limitation to the efficacy and application of TP5. iRGD (CRGDK/RGPD/EC) has been introduced to certain anticancer agents, and increased specific tumor penetrability of drugs and cell internalization have been observed. In the present study, we fused this iRGD fragment with the C-terminal of TP5 to yield a new product, TP5-iRGD. Cell attachment assay showed that TP5-iRGD exhibits more extensive attachment to the melanoma cell line B16F10 than wild-type TP5. Tumor cell viability assay showed that iRGD conjugation with the TP5 C-terminus increases the basal antiproliferative activity of the pentapeptide against the melanoma cell line B16F10, the human lung cancer cell line H460, and the human breast cancer cell line MCF-7. Subsequent injections of TP5-iRGD inhibited invivo melanoma progression more efficiently than the native TP5. Murine spleen lymphocyte proliferation assay also showed that TP5-iRGD and the parent pentapeptide feature nearly identical spleen lymphocyte proliferation activities. We built an integrin αvβ3 and TP5-iRGD computational binding model to investigate the mechanism by which TP5-iRGD promotes increased activity further. Conjugation with iRGD promotes binding to integrin αvβ3, thereby increasing the tumor-homing efficiency of the resultant peptide. These experimental and computational observations of increased TP5-iRGD activity help broaden the usage of TP5 and reflect the great application potential of the peptide as an anticancer agent.

Behandlung des Herpes simplex recidivans mit Thymopoetin-Pentapeptid

Treatment resistant recurrent herpes simplex persisting for years in 7 patients was treated with thymopoietin pentapeptide for 6 weeks, 50 mg subcutaneously three times per week. During treatment and follow-up of 6 weeks a pronounced reduction of frequency and duration of recurrences were observed. There was some tendency for normalisation of deranged lymphocyte and granulocyte function. The mode of action of thymopoietin pentapeptide in recurrent herpes simplex remains uncertain. An indirect effect via stimulation of production of interferon may be assumed.

Enhancement of Antitumor Effects of Combined Chemoimmunotherapy

The spontaneously metastatic murine pancreatic tumor, PAN 2, was used to evaluate established regimens of combined chemoimmunotherapy with 5-fluorouracil (5-FU) and levamisole and new protocols based on the immunomodulator, thymopoietin pentapeptide (TP-5). The combination of 5-FU and levamisole reduced the final tumor size by 32% and the mean number of lung metastases by 71%. Based on flow cytometric analysis, the combination treatment increased the percent of helper/inducer (CD4+) lymphocytes and reduced the number of effector (suppressor/cytotoxic) lymphocytes (CD8+). A second combination using 5-FU and TP-5 produced a reduction in tumor growth rate of 52%, with an 88% suppression of lung metastases with TP-5/5-FU (vs. levamisole/5-FU) treatment. The TP-5 treatment also increased splenic T-lymphocyte responsiveness to nonspecific mitogens by 2.3-fold. These results suggest a correlation between enhanced T-lymphocyte functional parameters and reduced tumor growth and metastatic spread produced by these combination therapies. Since TP-5 has been demonstrated to be a superior immunomodulator compared to levamisole, the greater therapeutic effect of TP-5 vs. levamisole further supports the postulated role of immunopotentiation in the success of combined chemoimmunotherapy.

Immunomodulators and wound healing.

The synthetic immunomodulators muramyl dipeptide (MDP), thymopoietin pentapeptide (TP5), and CP-46,665 were examined for their effects on wound healing in mice. We found no differences in wound disruption strength between immunomodulator-treated animals and saline controls on days 11, 14, and 21. The only exception was with high-dose CP-46,665, which produced weakened wounds on day 14 (p less than 0.05) and 21 (p less than 0.01). CP-46,665 was further studied by injecting high and low doses 48 hours before or after wounding. No differences were seen for these groups compared to controls at 11 and 21 days. Finally, to simulate a common clinical situation, mice were subjected to a 10% total body surface area (TBSA) burn to the right paraspinal region. Twenty-four hours later, a left paraspinal incision was performed with simultaneous injection of saline, Corynebacterium parvum (C. parvum), or low-dose TP-5, MDP, or CP-46,665. At 11 days, no detriment in wound healing was found for burned control or any of the immunomodulator-treated animals except in the C. parvum-treated mice, with significantly weakened skin strips (p less than 0.001). While C. parvum may be detrimental to wound healing, the synthetic modulators tested appear to have little effect on wound healing.

Effects of a combination of thymopoietin pentapeptide (TP-5) and interleukin 2 on lymphocyte subsets and helper activity of cord blood T cells

There have been several reports that lymphocytes of human cord blood have poor functional properties because of their immaturity and/or the presence of suppressor cells. We studied here the in vitro effects of thymopoietin pentapeptide (TP-5) and interleukin 2 (IL-2) on cord blood T cells. Lymphocyte subsets were analyzed by flow cytometry through the use of monoclonal antibodies after a 48 h culture period in TP-5 (optimal dose; 1μg/ml) and/or IL-2 (non-mitogenic dose used; 1% vol/vol). OKT 8-positive cells were significantly decreased after treatment in combination with TP-5 and IL-2. But there were no changes in the propotion of OKT 3-, T4-, T11- and Ial-positive cells. Poor helper activity of cord blood T cells, which was examined by enhancing activity of immunoglobulin-production of normal adult non-T cells stimulated by pokeweed mitogen, was enhanced to a significant level of IgG production after treatment in combination with two agents. Crude IL-2 activity was reevaluated through the use of recombinant IL-2.

Successful immunological reconstitution of CID with predominant T-cell defect by means of thymopoietin pentapeptide (TP5)

Successful immunological reconstitution of CID with predominant T-cell defect by means of thymopoietin pentapeptide (TP5)

Bone marrow transplantation and thymopoietin pentapeptide treatment in two infants with immunodeficiency with predominant T-cell defects

Two infants with immunodeficiency with predominant T-cell defects received transplants of HLA-identical bone marrow cells along with thymopoietin pentapeptide (TP-5) treatment and no prior immunosuppressive therapy. Both patients achieved durable engraftment with early reconstitution of cell-mediated immunity. The study of cell surface antigens with monoclonal antibodies (MoAb) revealed that the early appearance of T-cell subsets defined by OKT4 and OKT8 MoAb occurred. Neither of the patients showed any signs or symptoms of graft versus host disease over a 1-year period. This experience suggests that patients with T-cell deficiency who do not benefit from thymic hormones alone can be successfully treated by bone marrow transplantation. The association of TP-5 with bone marrow transplantation seems to induce and early and stable reconstitution and to protect against fatal post-transplant infection.

Letterer-Siwe disease in an octogenarian

The case of an 81-year-old woman suffering for about 1 year from a typical form of Letterer-Siwe disease (LSD) is reported. The only important systemic involvement was hepatosplenomegaly. The patient was treated with steroids and vinblastine and then with thymopoietin pentapeptide. This last drug proved useful for decreasing the dose of steroid and thus for checking the appearance of new skin lesions. The ultrastructural investigations, carried out before and after vinblastine, showed the presence in some histiocytosis X cells (HXC) of coated Birbeck granules (BG). Immunoelectron microscopy showed about 90% of HXC to be OKT6+ and the OKT6 labeling of these cells to be similar to that of the Langerhans cells of normal skin. Five percent of OKT6+ cells apparently contained no Langerhans granules.

Thymopoietin pentapeptide treatment of primary immunodeficiencies: Aniti F, Fiorilli M, Quinti I, Seminara R, Businco L, Galli E, Rossi P, Goldstein G: Lancet 6:551, 1983

Thymopoietin pentapeptide treatment of primary immunodeficiencies: Aniti F, Fiorilli M, Quinti I, Seminara R, Businco L, Galli E, Rossi P, Goldstein G: Lancet 6:551, 1983

Changes in surface antigens of immature thymocytes under the influence of T-cell growth factor and thymic factors.

Peanut agglutinin-positive thymocytes, peanut agglutinin-negative thymocytes, cortisone-resistant thymocytes, and unfractionated thymocytes were prepared from congeneic C57BL/6 Tla mice. By using surface iodination and immunoprecipitation of solubilized antigen with specific antisera (e.g., anti-H-2D, anti-TL, anti-Qa2/3, and anti-gp70), the released specific antigens were electrophoresed on polyacrylamide gels, and their radioactivity was measured. The relative percentages of surface antigens H-2D, TL, Qa2/3, and gp70 were 3.2%, 47.5%, 2.5%, and 46.8%, respectively, for peanut agglutinin-positive thymocytes; 31.8%, 4.4%, 32.7%, and 31.1%, respectively, for cortisone-resistant thymocytes; 13.2%, 28.7%, 12.3%, and 45.8%, respectively, for peanut agglutinin-negative thymocytes; and 7.7%, 27.1%, 4.3%, and 60.9%, respectively, for unfractionated thymocytes. After incubation with thymosin fraction V or T-cell growth factor (interleukin II) for 20 hr, the changes in surface antigens of peanut agglutinin-positive thymocytes closely correlated with their normal maturation (i.e., H-2D increases and TL decreases). Thymic factors (e.g., thymosin alpha 1, thymopoietin pentapeptide, facteur thymic serique) had only small or no effects on surface antigens of peanut agglutinin-positive thymocytes. The results suggest that peptides yet to be identified in thymosin fraction V may play an important role in intrathymic evolution and that T-cell growth factor is possibly a peripheral signal derived from activated T cells that modulates T-cell receptors and may be a critical regulator of intrathymic cellular development.

Synthetic Immunomodulators for Prevention of Fatal Infections in a Burned Guinea Pig Model

Individuals who have suffered severe trauma, such as burns, have a high incidence of infection associated with impaired host resistance. Nonspecific stimulators of host defense mechanisms, i.e., immunomodulators, may be of benefit in such situations. A small animal model (guinea pigs) was developed to study the efficacy of immunomodulators in burns. Anesthetized animals received a 20% total body surface area, full-thickness, scald burn. There was no mortality associated with this injury, but these animals were highly susceptible to challenge with Pseudomonas aeruginosa strain 1244 by direct injection into the burn wound within 24 hours of injury. This susceptibility persisted about 7 days. The standard model adopted was to injure animals, then challenge with 1 median lethal dose (LD50) of P. aeruginosa 96 hours after injury. Using this model, six synthetic immunomodulators were tested: CP-20,961, CP-46,665, muramyl dipeptide, thymopoietin pentapeptide (TP-5), levamisole, and lithium. Drug administration began 24 hours after injury and ended prior to challenge with P. aeruginosa at 96 hours. CP-20,961, muramyl dipeptide, levamisole, and lithium all had no beneficial effect on survival. A single dosage (0.3 mg/kg, I.V.) of CP-46,665, administered 24 hours postinjury, increased the survival rate from 50% to 85% and mean survival time (MST) from 8.2 days to 12.4 days. TP-5, given in four doses (0.1 mg/kg, I.V. each) every 24 hours, increased the survival rate from 40% to 80% and MST from 6.9 days to 11.6 days. These data show that immunomodulators could be of benefit in burns, but also that not all agents are effective in this particular situation.

THYMOPOIETIN PENTAPEPTIDE TREATMENT OF PRIMARY IMMUNODEFICIENCIES

26 patients with primary immunodeficiencies (3 infants with severe combined immunodeficiency [SCID] 3 with DiGeorge syndrome, 6 with T-cell defect or SCID with B cells, 4 with common variable hypogammaglobulinaemia and associated T-cell defect, 5 with ataxia-telangiectasia, and 5 with hyper-IgE syndrome) were treated with thymopoietin pentapeptide (TP-5) at a dose of 0·5 mg/kg daily for 2 weeks and then 3 times a week at 0·5 mg/kg for 10 weeks. 3 patients with DiGeorge syndrome and 3 with primary T-cell defect demonstrated pronounced clinical and immunological improvement during treatment. None of the patients with SCID and 3 of 6 patients with SCID with B cells or primary T-cell defect showed any clinical or immunological changes during therapy. In 5 patients with ataxia-telangiectasia clinical manifestations and immunological tests were unchanged by TP-5. Abnormality of T cells in cases of hyper-IgE syndrome was not corrected by TP-5 treatment.

Thymopoietin pentapeptide (TP-5) improves clinical parameters and lymphocyte subpopulations in atopic dermatitis

In a double-blind prospective study, eighteen patients with atopic dermatitis (AD) were treated with thrice-weekly injections of 50 mg thymopoietin pentapeptide (TP-5) or placebo for 6 weeks. Clinical parameters, lymphocyte subsets defined by monoclonal antibodies, and serum IgE were modified. Younger patients (age less than 34) responded to TP-5 with much greater improvement in severity scores than TP-5-treated patients of age greater than 34 or than placebo-treated patients of either age group (p less than 0.05). Both absolute lymphocytes and OKT8+ cytotoxic/suppressor cells were significantly increased (p less than 0.05) in the TP-5 group, whereas they were not significantly increased in the placebo group (p greater than 0.05). Conversely, Ia+ cells were significantly increased in the placebo group (p less than 0.05), but remained the same in the TP-5 group (p greater than 0.05). Serum IgE levels were not significantly altered in either group. Thus, TP-5 had a beneficial clinical effect in AD, especially in younger patients, and increased the reduced OKT8+ cytotoxic/suppressor T cells and prevented an increase of Ia+ cells during pollen season.

Immuno-regulating peptides, I. Synthesis and structure-activity relationships of thymopentin analogs.

Seventeen peptides, related to thymopoietin pentapeptide, L-arginyl-L-lysyl-L-aspartyl-L-valyl-L-tyrosine (thymopentin) were synthesized by the stepwise strategy in solution. Of these, L-arginyl-L-lysyl-L-aspartic acid and L-arginyl-L-lysyl-L-aspartyl-L-valine, shortened from the C-terminus of the pentapeptide, exhibit significant immuno-stimulating potencies, exceeding those of thymopentin, both in vitro and in vivo immunological tests. Studies on the structure-activity relationships suggest that the potencial active site of thymopoietins is very sensitive to the N- and C-terminal elongations of the peptide chain. For thymic hormones, an active site carrying cumulative chemical signals is proposed instead of well-defined active centers.

Studies of thymopoietin pentapeptide (TP5) on experimental tumors: I. TP5 relieves immunosuppression in tumor-bearing mice

The allogeneic and syngeneic immune responses of tumor-bearing mice (C57BL/6 mice bearing 3LL and DBA mice bearing P815) were evaluated by the cytotoxic lymphocyte precursor unit (CLP-U) and MLC. In general, tumor-bearing mice showed slightly enhanced immune responses 4 days after tumor inoculation. This enhanced immune response rapidly declined and about 7–10 days after tumor inoculation, both allogeneic and syngeneic responses were markedly lower than normal. Mice treated with TP5, starting 2 weeks before tumor inoculation, retained normal or enhanced allogeneic and syngeneic responses up to 3 weeks after tumor inoculation. When this tumor-induced suppressive effect was studied in cell transfer experiments, spleen cells from tumor-bearing mice enhanced the growth of tumors in syngeneic recipients whereas spleen cells from TP5-treated mice inhibited the growth of tumors in syngeneic recipients. Moreover, the spleen cells from TP5-treated mice also showed enhanced cytotoxic activity against tumor cells in vitro. These findings suggest that the tumors, after a transient stimulatory phase, induced immune suppressive mechanisms in the hosts' immune defenses. Treatment with TP5 prevented the development of these immune suppressive effects and spleen cells from TP5-treated tumor-bearing mice inhibited tumor growth in freshly tumor-inoculated recipients.

Determination of T lymphocyte subpopulations by monoclonal antibodies in rheumatoid arthritis. Influence of immunomodulating agents

The pathogenesis of rheumatoid arthritis is unknown, but clear abnormalities of the immune system are well documented in this disease. We therefore evaluated T cell subpopulations in patients with rheumatoid arthritis using monoclonal antibodies previously shown to react with all T cells (OKT3), with inducer/helper T cells (OKT4) and with suppressor/cytotoxic T cells (OKT8). These investigations disclosed evidence of a significant decrease in the number of OKT8 + cells/mm 3 and a high inducer-helper/suppressor-cytotoxic (OKT4 +/OKT8 +) ratio in active rheumatoid arthritis. A modest number of patients with active arthritis were treated with levamisole or with synthetic thymopoietin 32–36 (thymopoietin pentapeptide or TP-5). These individuals responded with ratio decreases to more normal levels. Our data support the hypothesis that monoclonal T cell antibodies may offer an important tool for the further evaluation of patients with rheumatoid arthritis and their individual response to treatment.

Effect of thymopoietin pentapeptide (TP5) on autoimmunity. I. TP5 suppression of induced erythrocyte autoantibodies in C3H mice.

C3H mice (young and old), when immunized with the cross-reacting rat erythrocytes, produced erythrocyte autoantibodies that usually persisted for more than 10 weeks. I.P. injection of thymopoietin pentapeptide (TP5) once or thrice weekly accelerated the loss of erythrocyte autoantibodies 7 weeks after immunization; 10 ng of TP5 was the optimal dose. The rat agglutinin responses of these immunized mice were unaffected by TP5 during the whole period of study. Spleen cells from rat erythrocyte-immunized mice, when transferred to syngeneic recipients undergoing similar immunization schedules, delayed the appearance of erythrocyte autoantibodies in the recipients. A greater delay was observed when spleen cells were taken from mice that had also received TP5 treatment.

Immunokinetics of a single dose of thymopoietin pentapeptide.

14 patients with classical or definite rheumatoid arthritis and a low number of E-rosette forming cells were given single doses of 5 mg and 50 mg of thymopoietin intravenously. Thymopoietin pentapeptide produced a dose-related sustained increase in E-rosette forming lymphocytes as shown by the decrease of thymopoietin dependent rosetting ratio. A single dose of 50 mg restored the number of E-rosette forming cells to normal after 12 h and this effect lasted 60 to 7 days. With the administration of 5 E-rosette forming cells markedly increased after 12 h and returned to the pretreatment level on the 2nd day. These immunokinetic data clarify some aspects of the clinical pharmacology of thymopoietin pentapeptide and must be considered for a rational schedule of treatment with the drug.

Effect of methisoprinol, levamisole and thymopoietin pentapeptide on lymphocyte ADA activity during mitogenic stimulation

Effect of methisoprinol, levamisole and thymopoietin pentapeptide on lymphocyte ADA activity during mitogenic stimulation

Immunokinetics of a single dose of thymopoietin pentapeptide

Immunokinetics of a single dose of thymopoietin pentapeptide