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PubMed1985

Mechanisms of action of two new immunomodulators.

Despite antibiotics, infection remains a significant problem in surgical patients. The reasons are multiple, and include acquired immunologic deficiencies that are seen in malnutrition, sepsis, trauma, and burns. Two immunomodulators, thymopentin (TP-5) and CP-46,665, have been shown to improve survival in infectious animal models of such deficiencies. We investigated the mechanism of action in guinea pigs subjected to a burn of 30% of the total body surface area. These animals received 0.3 mg/kg of thymopentin, 0.3 mg/kg of CP-46,665, or saline solution. Neutrophils, macrophages, and serum samples were obtained from the animals and tested for their ability to phagocytose and kill Pseudomonas aeruginosa. The serum was tested for its ability to opsonize Escherichia coli. Thymopentin was found to improve neutrophil function on postburn days 2 and 4 and to improve macrophage function on postburn day 4. CP-46,665 was found to improve both macrophage function and opsonization on postburn day 2.

Adjuvants, Immunologic↗
PubMed1996

The protective role of the immunomodulator AS101 against chemotherapy-induced alopecia studies on human and animal models.

The immunomodulator AS101 has been demonstrated to exhibit radioprotective and chemoprotective effects in mice. Following phase-I studies, preliminary results from phase-II clinical trials on non-small-cell-lung-cancer patients showed a reduction in the severity of alopecia in patients treated with AS101 in combination with chemotherapy. To further substantiate these findings, the present study was extended to include 58 patients treated either with the optimal dose of 3 mg/m2 AS101 combined with carboplatin and VP-16, or with chemotherapy alone. As compared with patients treated with chemotherapy alone, there was a significant decrease in the level of alopecia in patients receiving the combined therapy. The newly developed rat model was used to elucidate the protective mechanism involved in this effect. We show that significant prevention of chemotherapy-induced alopecia is obtained in rats treated with Ara-C combined with AS101, administered i.p. or s.c. or applied topically to the dorsal skin. We show that this protection by AS101 is mediated by macrophage-derived factors induced by AS101. Protection by AS101 can be ascribed, at least in part, to IL-1, since treatment of rats with IL-1 RA largely abrogated the protective effect of AS101. Moreover, we demonstrate that in humans there is an inverse correlation between the grade of alopecia and the increase in IL-1 alpha. In addition, protection by AS101 could be related to PGE2 secretion, since injection of indomethacin before treatment with AS101 and Ara-C partly abrogated the protective effect of AS101. To assess the ability of AS101 to protect against chemotherapy-induced alopecia, phase-II clinical trials have been initiated with cancer patients suffering from various malignancies.

Alopecia↗
PubMed1998

TNF modulates susceptibility to UVB-induced systemic immunomodulation in mice by effects on dermal mast cell prevalence.

The mechanisms by which UV radiation is immunosuppressive are controversial, but there is growing evidence that processes of UVB-induced suppression of the immune response towards a sensitizing antigen are different if this antigen is applied to irradiated compared with non-irradiated sites. Consistent with this is our recent observation (Hart et al., J. Exp. Med. 1998. 187: 2045-2053) that the prevalence of dermal mast cells determines the extent of susceptibility of different mouse strains to UVB-induced systemic, but not local, immunosuppression. Using C57BL/6 and BALB/c mice exposed to low and high doses of UVB, respectively, in the presence of a polyclonal anti-TNF antibody, we found that TNF is directly involved as a mediator in the suppression by UVB of local immune responses. To determine whether TNF indirectly regulates UVB-induced systemic immunomodulation by altering the prevalence of dermal mast cells, dermal mast cell numbers in gene-targeted mice deficient in TNF or TNF receptors (p55/p75-/- mice) were quantified by video image analysis. A reduced dermal mast cell prevalence in these mice correlated with decreased susceptibility for systemic immunosuppression caused by UVB. We hypothesize that TNF is one molecule that controls dermal mast cell prevalence by as yet unknown mechanisms. However, it is the mediators released from mast cells upon UVB-induced degranulation, which do not include TNF, that directly signal suppressive events relevant to systemic immunosuppression.

Animals↗
PubMed1993

Inhibition of acute, experimental autoimmune encephalomyelitis by the synthetic immunomodulator linomide.

Linomide (LS-2616, quinoline-3-carboxamide) is a synthetic immunomodulator that stimulates natural killer cell activity and activates several lymphocytic subpopulations in experimental animals and humans. In this study we determined the effect of oral treatment with linomide on the development of experimental autoimmune encephalomyelitis, an animal model for immune-mediated human demyelinating disorders. Experimental autoimmune encephalomyelitis was induced in SJL/J mice and in an outbred strain of rats (Sabra) by subcutaneous injection of spinal cord homogenate in adjuvant followed by inoculation with Bordetella pertussis. Linomide was administered in drinking water, at an estimated dose of 50 to 100 mg/kg/day. None of the linomide-treated mice (0/41) and Sabra rats (0/15) developed any clinical or pathological signs of experimental autoimmune encephalomyelitis, whereas almost all control animals (48/53 and 18/19, respectively) were severely paralyzed and 64.5% died from the disease. Lymphocytes obtained from linomide-treated animals had reduced in vitro proliferative responses to guinea pig myelin basic protein, proteolipid protein of the myelin, and tuberculin-purified protein derivative, unlike antigen-independent proliferation which was rather unaffected. Natural killer cell activity (tested by a cytotoxic assay on radiolabeled YAC-1 target cells) was significantly enhanced in mice treated with linomide. Our results indicate that modulation of the immune system with linomide leads to complete inhibition of experimental autoimmune encephalomyelitis in the absence of systemic immunosuppression. Linomide could therefore be of use in future clinical trials for the treatment of human autoimmune demyelinating disorders.

Adjuvants, Immunologic↗
PubMed2003

Placental immunomodulator ferritin, a novel immunoregulator, suppresses experimental arthritis.

OBJECTIVE: To determine the effect of treatment with C48, the recombinant cytokine-like domain of the novel human placental immunomodulator ferritin (PLIF) immunoregulator, on zymosan-induced arthritis (ZIA) in mice and on adjuvant-induced arthritis (AIA) in rats. METHODS: The in vitro effect of PLIF/C48 was tested in mixed lymphocyte cultures (MLCs) of allogeneic mouse splenocytes. Arthritis was induced by intraarticular injection of zymosan into naive mice and by subcutaneous injection of Mycobacterium tuberculosis into rats. C48 was injected intraperitoneally daily from day 3 to day 9 or from day 7 to day 13 after induction of synovitis by zymosan, and every other day from day 2 to day 14 after induction of AIA. Swelling of the joints and histologic features of the synovium were assessed. Th1 and Th2 cytokines were quantified by enzyme-linked immunosorbent assay. RESULTS: Both PLIF and C48 significantly inhibited the in vitro immunoreactivity of mouse splenocytes in MLCs. Treatment of ZIA mice and AIA rats with C48 effectively reduced joint swelling. C48 treatment reduced synovial lining thickening, numbers of mononuclear cells and histiocytes, as well as cartilage destruction and bone erosions. In vitro, activated splenocytes from C48-treated ZIA and AIA animals produced significantly higher levels of interleukin-10 (IL-10). In animals with ZIA, this was accompanied by lower levels of tumor necrosis factor and IL-2. CONCLUSION: Human PLIF and C48 were shown to exert cross-species immunosuppressive activity in vitro. The in vivo suppression of articular inflammation in the experimental models of ZIA and AIA was the result of treatment with the antiinflammatory human C48. These results suggest that treatment with C48 may offer an effective immunotherapeutic means of controlling inflammatory polyarthritis.

Adjuvants, Immunologic↗
PubMed1982

Immunomodulating effect of human placenta-eluted gamma globulins in rheumatoid arthritis.

Patients who had active and severe rheumatoid arthritis (RA) were treated with human placenta-eluted gamma globulins (PEGG) composed of purified IgG eluted from trophoblastic cells. A control group of RA patients received retroplacental gamma globulins with no clinical effects. Seven of eleven treatments with PEGG showed good (4 patients) or very good (3 patients) clinical results. All patients had immunologic modifications demonstrated by a significant increase in active E-rosette-forming cells and mitogen responsiveness. The precise mechanism of immunomodulating effect of PEGG should be further investigated.

Adult↗
PubMed1986

Successful treatment of autoimmunity in MRL/1 mice with LS-2616, a new immunomodulator.

Autoimmune MRL/1 mice were treated with a recently developed substance with immunomodulating properties, LS-2616. Treatment was initiated at the age of 8 weeks, before the onset of clinically apparent disease, and at 16 weeks of age, after development of established lupus disease. Beneficial therapeutic effects were obtained, even when LS-2616 was administered at the lowest dose tested (1 mg/mouse/week) to 16-week-old mice. The effects of LS-2616 on longevity, as well as on development of lymphadenopathy, splenomegaly, glomerulonephritis, and vasculitis, were pronounced and were comparable with those of cyclophosphamide. The results obtained suggest a potential role for LS-2616 in the treatment of autoimmune disease in humans.

Adjuvants, Immunologic↗
PubMed2005

Immunomodulation with interferon-gamma and colony-stimulating factors for refractory fungal infections in patients with leukemia.

BACKGROUND: Invasive fungal infections (IFI) in immunocompromised patients are associated with significant morbidity and mortality, despite appropriate antifungal treatment and recovery from neutropenia. The outcome of these infections depends significantly on the overall state of immunosuppression, including mainly the phagocytic system (neutrophils and macrophages). Interferon-gamma (IFN-gamma), granulocyte-colony--stimulating factor (G-CSF) and granulocyte-macrophage-colony--stimulating factor (GM-CSF) are cytokines that enhance the activity of neutrophils and macrophages. METHODS: The authors reported 4 patients with leukemia and refractory invasive candidiasis or trichosporonosis despite 1-13 months of appropriate antifungal treatment. RESULTS: Cytokines were administered for 1.5-5 months without significant toxicity. For each patient, initiation of interferon-gamma plus a colony-stimulating factor resulted in a clinical response. The contribution of cytokines to control the fungal infection in these 4 patients was suggested by the strong inflammatory reaction observed in the 2 patients who had an immediate response (within 7 days of initiation of cytokine therapy) and by the good outcome in the 2 other patients in whom antifungal agents were discontinued at the start of cytokine therapy. CONCLUSIONS: These data suggested a potential role for immunomodulation in patients with leukemia with refractory invasive fungal infections.

Adolescent↗
PubMed1992

Immunomodulation of streptococcal cell wall-induced arthritis. Identification of inflammatory cells and regulatory T cell subsets by mercuric chloride and in vivo CD8 depletion.

Streptococcal cell wall (SCW)-induced arthritis is a chronic, erosive polyarthritis which can be induced in susceptible Lewis rats by one intraperitoneal injection of a sterile, aqueous suspension of SCW. The chronic phase of the disease is dependent on T cells. Mercuric chloride is an immunomodulating agent, causing autoimmunity in BN rats, but an OX8+ cell-mediated immunosuppression in Lewis rats. Therefore, we investigated the effect of mercuric chloride, whether or not combined with in vivo OX8 depletion, on SCW-induced arthritis in Lewis rats. We show that (a) depletion of OX8+ cells leads to a more chronic arthritis with a more rapid onset, (b) treatment with mercuric chloride induces a rapidly developing disease which is not chronic, and (c) treatment with mercuric chloride and OX8+ cell depletion induces an arthritis with a very rapid onset and enhanced chronicity. Together with histological data this suggests an important role for OX8+ T cells in controlling both the acute and chronic phase of the disease. In addition, mercuric chloride seems to induce an early activation of T cells resulting in an enhanced onset of disease, which is controlled later by enhanced activation of OX8+ cells.

Adjuvants, Immunologic↗
PubMed1993

Linomide, a novel immunomodulator that prevents death in four models of septic shock.

Intravenous injections of 50 micrograms Staphylococcus aureus enterotoxin B (SEB) or bacterial lipopolysaccharide (LPS) are lethal, provided that mice are simultaneously sensitized with either N-galactosamine (GalN) or the anti-glucocorticoid RU-38486. Similar to the synthetic glucocorticoid (GC) receptor agonist dexamethasone, pharmacological doses of the immunomodulator linomide (quinoline-3-carboxamide) prevent death in all four models of lethal septic shock (LPS + GalN, LPS + RU-38486, SEB + GalN, and SEB + RU-38486) and inhibit the secretion of tumor necrosis factor, one of the major intermediate effector molecules of SEB and LPS toxicity. In this system, cyclosporine A (CsA), although effective in suppressing SEB toxicity, fails to counteract the lethal effect of LPS. This observation, together with the fact that linomide acts in the presence of excess amounts of GC receptor antagonist, indicates that linomide functions in a different way to that of known immunosuppressive agents like CsA and GC.

Adjuvants, Immunologic↗
PubMed2005

The immunomodulator FTY720 interferes with effector functions of human monocyte-derived dendritic cells.

The potent immunomodulator FTY720 elicits immunosuppression via acting on sphingosine 1-phosphate receptors (S1PR), thereby leading to an entrapment of lymphocytes in the secondary lymphoid tissue. To elucidate the potential in vitro effects of this drug on human monocyte-derived DC, we used low nanomolar therapeutic concentrations of FTY720 and phosphorylated FTY720 (FTY720-P) and investigated their influence on DC surface marker expression, protein levels of S1PR and DC effector functions: antigen uptake, chemotaxis, cytokine production, allostimulatory and Th-priming capacity. We report that both FTY720 and FTY720-P reduce chemotaxis of immature and mature DC. Mature DC generated in the presence of FTY720 or FTY720-P showed an impaired immunostimmulatory capacity and reduced IL-12 but increased IL-10 production. T cells cultured in the presence of FTY720- or FTY720-P-treated DC showed an altered cytokine production profile indicating a shift from Th1 toward Th2 differentiation. In treated immature and mature DC, expression levels for two S1PR proteins, S1P1 and S1P4, were reduced. We conclude that in vitro treatment with FTY720 affects DC features that are essential for serving their role as antigen-presenting cells. This might represent a new aspect of the overall immunosuppressive action of FTY720 and makes DC potential targets of further sphingolipid-derived drugs.

Actins↗
PubMed2005

Role of cyclooxygenase-2 in immunomodulation and prognosis of endometrial carcinoma.

Although there are several hypotheses explaining the mechanisms of immune-privileged status of malignant tumor, the exact pathway has yet to be explored. Cyclooxygenase (COX)-2 plays a vital role in prognosis of cancer patients in terms of contribution to neoangiogenesis and apoptosis inhibition; however, the impact of COX-2 in immunomodulation has not been reported. We have evaluated the expression of COX-2 and its impact on infiltration of immune-competent cells into the tumor cell nest in endometrial carcinoma. Tissue specimens from 70 endometrial carcinoma patients who had undergone a curative resection were evaluated for COX-2 expression and host immune status (CD8+ T cells). COX-2 expression was associated with FIGO stage and myometrial invasion, but there was no statistically significant impact. CD8+ T cells within cancer cell nest (Nest CD8) were inversely correlated with the expression level of COX-2 (p = 0.0006). Nest CD8 became an independent predictor of patient survival (Hazard ratio = 10.300, p = 0.0304) in Cox's multivariate analysis. The expression level of COX-2 was found to be a significant predictor of disease relapse in univariate analysis (p = 0.0294) but not in multivariate analysis (p = 0.5949). In conclusion, increased nest CD8 produced a survival advantage in endometrial carcinoma patients. Moreover, tumor-produced COX-2, which reduces the infiltration of CD8+ T cells into cancer cell nests, may allow tumors to avoid immune surveillance.

Adult↗
PubMed2003

Analogs of 1alpha,25-dihydroxyvitamin D3 as pluripotent immunomodulators.

The active form of vitamin D(3), 1,25(OH)(2)D(3), is known, besides its classical effects on calcium and bone, for its pronounced immunomodulatory effects that are exerted both on the antigen-presenting cell level as well as directly on the T lymphocyte level. In animal models, these immune effects of 1,25(OH)(2)D(3) are reflected by a strong potency to prevent onset and even recurrence of autoimmune diseases. A major limitation in using 1,25(OH)(2)D(3) in clinical immune therapy are the adverse side effects on calcium and on bone. TX527 (19-nor-14,20-bisepi-23-yne-1,25(OH)(2)D(3)) is a structural 1,25(OH)(2)D(3) analog showing reduced calcemic activity associated with enhanced in vitro and in vivo immunomodulating capacity compared to the mother-molecule. Indeed, in vitro TX527 is more potent that 1,25(OH)(2)D(3) in redirecting differentiation and maturation of dendritic cells and in inhibiting phytohemagglutinin-stimulated T lymphocyte proliferation. In vivo, this enhanced potency of TX527 is confirmed by a stronger potential to prevent type 1 diabetes in nonobese diabetic (NOD) mice and to prolong the survival of syngeneic islets grafts, both alone and in combination with cyclosporine A, in overtly diabetic NOD mice. Moreover, these in vivo effects of TX527 are obtained without the adverse side effects observed for 1,25(OH)(2)D(3) itself. We believe therefore that TX527 is a potentially interesting candidate to be considered for clinical intervention trails in autoimmune diseases.

Adjuvants, Immunologic↗
PubMed1991

Polyphosphoinositide metabolism in polymorphonuclear cells from healthy and thermally injured rats: effect of the immunomodulator RU 41740.

Burn trauma is associated with alterations of various components of host defenses, including impaired neutrophil functions. In an animal model of experimental thermal injury, we studied if the modifications of cellular reactivity result from alterations in signalling systems by comparing polyphosphoinositide breakdown, particularly the production of inositol phosphates (IP, IP2 IP3), in healthy and burned rat polymorphonuclear neutrophil leukocytes (PMNs). Neutrophil activators such as N-formyl-methionyl-leucyl-phenylalanine (fMLP) and serum-opsonized zymosan increased in vitro production of inositol phosphates in PMNs from healthy rats. The immunomodulator RU 41740 had no effect by itself, but decreased the stimulating effect of fMLP and zymosan. In PMNs from burned rats, the stimulating effects of fMLP and zymosan were decreased, while RU 41740 stimulated inositol phosphate generation. In vivo treatment with RU 41740 inhibited the activation of phosphoinositide metabolism by fMLP or zymosan in healthy rat PMNs. Similar treatment of burned rats after injury restored the stimulating effect of fMLP and zymosan on inositol phosphate accumulation in PMNs. Thus, RU 41740 can modulate fMLP and zymosan receptor-mediated signal transduction, inducing an attenuation of the phosphatidylinositol hydrolysis response. After burn injury, when the activating effects of fMLP and zymosan are inhibited, RU 41740 can, on the contrary, stimulate phospholipase C-mediated polyphosphoinositide turnover and the formation of intracellular messengers such as IP3. These data show that RU 41740 has different effects on polyphosphoinositide metabolism in rat PMNs, according to the physiological and pathological state of the animals. Interestingly, it has a beneficial action on the post-burn decrease in PMN reactivity.

Animals↗
PubMed1994

Cytokine induction in mice by the immunomodulator imiquimod.

Imiquimod has been identified as a potent antiviral and antitumor agent in animal models. The biological activity associated with imiquimod has been attributed to its induction of interferon (IFN)-alpha. The present studies evaluated imiquimod administered orally for its ability to stimulate production of IFN and other cytokines in mice. The cytokine profile induced by imiquimod was compared with other known immunomodulators. Imiquimod was found to stimulate increased serum IFN in mice. Daily dosing of imiquimod for five consecutive days led to diminished production of IFN in mice as measured after the final dose. Elevated levels of serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 but not IL-1 alpha were found in serum from mice treated with imiquimod. Imiquimod produced significantly higher levels of IFN but lower levels of TNF and IL-6 and IL-1 alpha than lipopolysaccharide. Polyinosinic acid:polycytidylic acid induced significantly higher amounts of IFN but lower levels of TNF and IL-6 than imiquimod. Imiquimod stimulated significantly higher levels of IFN when compared with 2-amino-5-bromo-6-phenyl-4(3H)-pyrimidinone (ABPP) and similar levels of IFN when compared with tilorone. Neither ABPP nor tilorone induced TNF or IL-6. Finally, imiquimod stimulated TNF, IFN, and IL-6 production in cultures of mouse spleen and bone marrow cells. These studies demonstrate that imiquimod induces not only IFN but other cytokines as well, all of which may contribute to its biological activity.

Aminoquinolines↗
PubMedDate not supplied

Immunomodulation by the copolymer glatiramer acetate.

Glatiramer acetate (GA; Copaxone, also known as Copolymer 1 or Cop-1), a copolymer of amino acids, is very effective in the suppression of experimental autoimmune encephalitis (EAE), the animal model for multiple sclerosis (MS), in various species including primates. The immunological cross-reaction between the myelin basic protein and GA serves as the basis for the suppressive activity of GA in EAE, by the induction of antigen-specific suppressor cells. The mode of action of GA is by initial strong promiscuous binding to major histocompatibility complex class II molecules and competition with MBP and other myelin proteins for such binding and presentation to T cells. Suppressor T cells induced by GA are of the Th2 type, migrate to the brain and lead to in situ bystander suppression. Clinical trials with GA, both phase II and phase III, were performed in relapsing-remitting MS (RRMS) patients, and demonstrated efficacy in reducing the relapse rate, decreasing MRI-assessed disease activity and burden and slowing progression of disability. GA is generally well tolerated and is not associated with influenza-like symptoms and formation of neutralizing antibodies seen with beta-interferons. It exerts its suppressive effect primarily by immunomodulation, and has recently shown ameliorating effect in a few additional autoimmune disorders as well as in graft rejection. At present GA is considered a valuable first-line treatment option for patients with RRMS.

Animals↗
PubMed1986

Effect of the immunomodulator tilorone on antipyrine disposition in the rat.

A wide variety of immunomodulators, including the synthetic interferon inducer tilorone (2,7-bis[2-(diethylamino)ethoxy]fluoren-9-one), have been shown to inhibit cytochrome P-450-dependent drug metabolism in vitro. In an effort to determine if tilorone also inhibits drug metabolism in vivo, we examined the effect of this agent on the disposition of antipyrine in the rat. Administration of tilorone hydrochloride (50 mg X kg-1 X d-1) 4 d resulted in a 42% reduction in antipyrine clearance and a 71% increase in plasma half-life. Administration of a single dose of tilorone hydrochloride (50 mg/kg) 48 h prior to antipyrine was found to cause a similar alteration in antipyrine clearance and half-life. Both treatment regimens were also found to produce a substantial weight loss in the pretreated animals. Preliminary studies indicated that tilorone treatment reduced food and water consumption in the rat. Therefore, the effect of a 75% decrease in food and water consumption on antipyrine disposition was also examined. This magnitude of restriction had no detectable effect on antipyrine elimination. Thus, tilorone results in a substantial reduction of the in vivo metabolic clearance of antipyrine and appears to be a useful compound for studying the dynamic interaction between the drug metabolizing and immune systems in vivo.

Animals↗