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At least 19 recordsLinked to original sources

PubMed1989

Influence of carbohydrates on the cytotoxicity of an aqueous mistletoe drug and of purified mistletoe lectins tested on human T-leukemia cells.

Partially and highly purified lectins from Viscum album L. (mistletoe) cause a dose-dependent decrease of viability of human leukemia cell cultures, MOLT-4, after 72 h treatment. The LC50 of the partially purified lectin was 27.8 ng/ml, of the highly purified lectin 1.3 ng/ml. Compared to the highly purified lectin a 140-fold higher protein concentration of an aqueous mistletoe drug was required to obtain similar cytotoxic effects on MOLT-4 cells. Cytotoxicity of the highly purified lectin was preferentially inhibited by D-galactose and lactose, cytotoxicity of the mistletoe drug and the partially purified lectin were preferentially inhibited by lactose and N-acetyl-D-galactosamine (GalNAc). Two lectin fractions with almost the same cytotoxic activity on MOLT-4 cells but with different carbohydrate affinities were isolated by affinity chromatography from the mistletoe drug: mistletoe lectin I with an affinity to D-galactose and GalNAc and mistletoe lectin II with an affinity to GalNAc. The lectin fractions and the mistletoe drug inhibited protein synthesis of MOLT-4 cells stronger than DNA synthesis. Furthermore a subpopulation of MOLT-4, resistant to cytotoxic doses of both the mistletoe drug and the mistletoe lectins, was shown to exhibit a reduced amount of GalNAc and N-acetyl-D-glucosamine in their cellular glycoproteins which are probably responsible for the binding of the cytotoxic lectins. These results indicate that lectins are the main toxins in the mistletoe drug.

Carbohydrates↗

PubMed1997

Induction of anti-mistletoe lectin antibodies in relation to different mistletoe-extracts.

Mistletoe extracts are frequently applied in adjuvant cancer treatment. The mistletoe lectins are especially suggested to mediate an antitumorous effect. During treatment with mistletoe lectin-rich extracts, anti-mistletoe lectin antibodies preferentially of the immunoglobulin G type are produced against mistletoe lectin (ML)-1. Interestingly, after application of mistletoe extracts containing natural micelles, anti-mistletoe lectin antibodies of the immunoglobulin G as well as one of the immunoglobulin E type were induced in parallel, suggesting that the nature and preparation of the antigens within the extract modifies immune responses. Anti-mistletoe lectin antibodies were shown to neutralize the cytotoxic effect of mistletoe lectin on peripheral blood mononuclear cells in vitro. Thus, the mode of application of these extracts seems to be of importance with respect to the therapeutic effect.

Antibodies↗

PubMed2000

Biological effects of natural and recombinant mistletoe lectin and an aqueous mistletoe extract on human monocytes and lymphocytes in vitro.

Mistletoe lectin is thought to constitute the active principle in extract preparations from mistletoe, which are widely used as immunomodulators in adjuvant tumor therapy. However, no study exists which compares the immunological potency of different well-defined mistletoe lectin preparations on human immune cells. Therefore, in the present study the biological effects of an aqueous mistletoe extract, standardized for mistletoe lectin I (eML), the isolated natural mistletoe lectin (nML), and the recombinant form of this lectin (rML) on human peripheral blood monocytes and lymphocytes were compared with respect to cell viability and cytokine induction. After 48-hr incubation of peripheral blood mononuclear cells (PBMC) with rML, nML, and eML, a continuous concentration-dependent decrease in cell viability was found with an IC50 of about 3 ng/ml for rML and nML and 10 ng/ml for eML, respectively. This effect also was seen when isolated lymphocytes and monocytes were separately incubated with the lectin preparations. After incubation of PBMC and isolated monocytes of 5/10 blood donors with eML, an increase in cell viability was found at lectin concentrations between 10 and 1,000 pg/ml. This effect was not seen with the pure lectin preparations nML and rML. After 48-hr incubation of PBMC with rML, nML, and eML, induction of IL-1-beta, TNF-alpha, IL-2, IL-6, and IL-10 but not IFN-gamma was measured. For IL-1-beta it could be shown that cytokine induction took place at a broad lectin concentration range (0.1-100 ng/ml). Cytokine levels varied greatly in the PBMC cultures of the different blood donors. When monocytes were separately incubated with eML, nML, and rML for 48 hr, high levels of IL-1-beta were found. In contrast, in cultures of separated lymphocytes from the same donors only a minimal production of IL-1-beta and no production of IFN-gamma was found after incubation with rML, nML, and eML. It is concluded that there are quantitative differences in the immunomodulatory effects of the mistletoe lectin preparations on human monocytes and lymphocytes. Therefore, measurement of cell viability and cytokine induction may be a diagnostic laboratory tool to determine the immunological potency of various mistletoe preparations and may help to clarify the clinical benefit of therapies with these substances.

Adult↗

PubMedDate not supplied

Mistletoe extracts standardized to mistletoe lectins in oncology: review on current status of preclinical research.

Since the identification and characterization of mistletoe lectins as pharmacologically active constituents at the end of the 1980s, research on mistletoe has made substantial advances. Mistletoe extracts are now available that are standardized in terms of the active mistletoe lectins (measured as mistletoe lectin I, ML I). This constitutes an indispensable precondition for reproducible investigations. Preclinical studies have shown that mistletoe extracts standardized in terms of ML I or pure ML I itself have highly potent cytotoxic and immunostimulating effects, predominantly on the cellular immune system. The immunostimulating effect is correlated with the apoptosis of immunologically active cells at low concentrations. Cytotoxic effects on tumor cells are likewise apoptosis-related, but at higher levels necrotic cell death predominates. Due to these properties, mistletoe extracts or pure ML I showed antitumoral activities in different animal models. The objective of this review is to present the current state of preclinical research on standardized mistletoe extracts which hence may be included in the category of rationalphytotherapy.

Animals↗

PubMed2006

Viscotoxins, mistletoe lectins and their isoforms in mistletoe (Viscum album L.) extracts Iscador.

The purpose of the following study was to evaluate the presence of the most frequently investigated pharmacologically active mistletoe compounds, viscotoxins (VT) and mistletoe lectins (ML), in European mistletoe Viscum album L. and in the pharmaceutical mistletoe preparations Iscador. Quantitative analysis of the VT isoforms A1, A2, A3, B, 1-PS, and U-PS in fresh mistletoe plant material from the three European subspecies of V. album, during fermentative extraction of mistletoe and in Iscador showed that the pharmaceutical proceeding specific for the preparation of Iscador warrants a high yield of VT. No degradation or transformation of VT during the production process became apparent. The VT compositions of the three host specific European subspecies of V. album, ssp. album, ssp. abietis, and ssp. austriacum, showed characteristic differences. They ensured the identification of the subspecies specific types of Iscador. ML contents of mistletoe extracts were reduced during fermentative extraction. The quantified contents of total ML were 261 +/- 9.3 ng/ml in Iscador M 5 mg spec. and 391 +/- 18.3 ng/ml in Iscador Qu 5 mg spec. Binding of ML to the glycoprotein asialofetuin (type 1) was found to be temperature dependent. Binding activity was increased to 250 % (ML I) and 410 % (ML II and ML III) respectively by decreasing temperature from 30 degrees C to 4 degrees C. 95% of ML could be eliminated from Iscador by affinity chromatography with immobilised glycoproteins at 0 degrees C. Quantitative extraction of ML from the crude extract and their analysis by SDS-PAGE revealed the presence of about 30 % ML I, 20% ML II, and 50% ML III in Iscador M 5 mg spec. and Iscador Qu 5 mg spec. The annual course of concentrations of ML and VT in the leaves of V. album showed maximal ML contents in December and culminaton of VT in June. Seasonal fluctuations of the composition of mistletoe imply the importance of fixed harvesting seasons.

Chemistry, Pharmaceutical↗

PubMed2002

Mistletoe extracts standardised in terms of mistletoe lectins (ML I) in oncology: current state of clinical research.

PURPOSE: The aim of this review is to present the current state of clinical oncological research on mistletoe extracts standardised in terms of the active substance mistletoe lectin. METHODS: This review focuses on studies with clearly defined mistletoe extracts standardised in terms of mistletoe lectins I, II, and III (calculated as mistletoe lectin I, ML I) which belong to the category of rational phytotherapy. That means that studies with anthroposophic or homeopathic drugs will not be included. RESULTS: There are several preclinical studies that show a cytotoxic and immunostimulating effect of mistletoe extracts, predominantly on the cellular immune system. The clinical database, however, is not as good as the experimental results. So far, no direct anticancer action or any improvement in time to tumour progression or overall survival in cancer patients has been seen. The first results of a randomised phase III study suggest that additive administration of a mistletoe preparation may improve the quality of life. CONCLUSION: Mistletoe therapy has not gained an established place in oncology. Further, well-planned randomised clinical investigations will be necessary to verify the first positive findings with regard to an improvement of quality of life in cancer patients.

Adjuvants, Immunologic↗

PubMed1999

Recognition of different antigens of mistletoe extracts by anti-mistletoe lectin antibodies.

Anti-mistletoe lectin-1 (ML-1) antibodies are produced during treatment of cancer patients with mistletoe extracts. However, little is known about their ability to recognise distinct epitopes present in mistletoe extracts. To estimate this, ML-1, ML-2 and ML-3 were analysed by Western blot analysis using high titred anti-ML antibody positive sera from cancer patients treated with different mistletoe extracts. In these experiments we could clearly demonstrate that anti-ML antibodies bind to ML-1 A- and B-chains and, in addition, that they recognised a spectrum of other antigens. This kind of immunological response varied from one individual to another and was not influenced by the different mistletoe extracts. Elution studies showed that anti-ML-1 A-chain or B-chain specific antibodies cross-reacted with A- or B-chains of the other lectins indicating homologies between these molecules (probably in the glycosylated side chain). However, the unglycosylated ML-3 A-chain was only detectable by antibodies specific for the ML-3 A-chain. From our data it has to be concluded that different epitopes of the mistletoe extracts are involved in the induction of the humoral immune response during mistletoe therapy and also that cross-reactivity between the different ML exist.

Adolescent↗

PubMed2004

Demonstration of antibodies to the chitin-binding mistletoe lectin (cbML) in tumor patients before and during therapy with an aqueous mistletoe extract.

Mistletoe extracts exert immunomodulatory properties in vivo and in vitro, and these effects have been related mainly to mistletoe lectin 1 (ML-1). Recently, a new chitin-binding mistletoe lectin (cbML) has been isolated and structurally characterized in these extracts. Aim of the present study was, therefore, to evaluate whether this cbML also affects immunocompetent cells and can for instance activate B-cells to produce anti-cbML-specific antibodies. Sera from patients with different tumors who were treated with the mistletoe extract ABNOBAviscum Mali (AM) 4 for at least 18 weeks were analysed before therapy and after 3, 6, 9, 12, 18, and 24 weeks. Sera were tested by ELISA against ML-1, -3, and cbML, isolated from a single mistletoe plant collected from an apple tree (Malus domestica). Eight of the 26 patients (31%) had IgG anti-cbML antibodies already before therapy, while only four had anti-ML-1 and -3 antibodies. Of the 18 anti-cbML negative patients before therapy 54% developed these antibodies during therapy, and there was a significant increase in anti-cbML antibody titers. In contrast, anti-ML-1 or -3-antibodies developed in almost 100% of the 25 patients being negative before therapy. These data indicate that cbML can induce immunological responses in patients treated with mistletoe extracts, although it seems to have lower antigenicity. Interestingly, anti-cbML antibodies can be observed in a low incidence also in individuals, not having yet received mistletoe therapy.

Adjuvants, Immunologic↗

PubMed1993

In vitro effects of mistletoe extracts and mistletoe lectins. Cytotoxicity towards tumor cells due to the induction of programmed cell death (apoptosis).

The in vitro effects of therapeutically administered mistletoe extracts (ABNOBAviscum) and pure mistletoe lectins (mainly mistletoe lectin I) on a variety of human and murine tumor cell lines have been investigated. Mistletoe extracts and purified mistletoe lectins inhibited in vitro the growth of all tumor cell lines tested including B cell hybridomas, P815, EL-4, Ke37, MOLT-4 and U937. The mechanism of growth arrest was shown to be due to the induction of programmed cell death (apoptosis). Thus, fragmentation of genomic DNA into oligonucleosomal bands of approximately 200 base pairs in length was observed within 20 h when tumor cells were incubated with mistletoe extracts or lectins. These data point to a rational basis for the direct cytotoxic effects of mistletoe extracts and lectins apart from the postulated immunostimulatory properties of these agents.

Adjuvants, Immunologic↗

PubMed1997

Oligoclonal in vitro response of CD4 T cells to vesicles of mistletoe extracts in mistletoe-treated cancer patients.

Mistletoe (Viscum album) extracts are widely used in adjuvant cancer therapy. We have investigated the in vitro responsiveness of T cells from mistletoe-treated cancer patients and untreated healthy donors to various preparations of mistletoe extracts. Proliferation of peripheral blood mononuclear cells from treated but not from untreated patients was observed in response to therapeutically used mistletoe extracts prepared from apple (mali) or pine (pini) host trees. The strongest proliferation was induced by a vesicle preparation of mali extract. Activation was strongly inhibited by interleukin-10. Using a newly developed flow-cytometry assay, we determined that cell growth was restricted to CD4 T cells. Analysis with a panel of monoclonal antibodies against the variable region of the T cell receptor beta chain (V beta) revealed an oligoclonal pattern of CD4 T cell activation. These results indicate that therapeutic administration of mistletoe extracts sensitizes a restricted set of CD4 T lymphocytes in mistletoe-treated patients.

CD4-Positive T-Lymphocytes↗

PubMedDate not supplied

Activation of dendritic cells by an aqueous mistletoe extract and mistletoe lectin-3 in vitro.

BACKGROUND: The function of dendritic cells (DC), the most important cell population for the induction of specific immune responses, is often altered in cancer patients. Since mistletoe extracts are applied to tumour patients, their influence on the activation/generation of DC was investigated. MATERIALS AND METHODS: Monocytes from healthy individuals were stimulated with the mistletoe extract (HM) or the mistletoe lectin 3 (ML-3) in the presence or absence of GM-CSF/IL-4. RESULTS: HM slightly but significantly stimulated the expression of CD83 but not CD1a in the presence of GM-CSF/IL-4, while in their absence only CD86 was activated. In pre-generated immature DC, HM and ML-3 enhanced the expression of CD86 but did not significantly activate CD83/CD1a. There was no relevant influence on the expression of HLA-class-I or class-II molecules. CONCLUSION: For the first time, our data demonstrate an influence of a mistletoe extract on the activation/generation of DC, but it remains to be elucidated whether the function of DC is also activated and especially whether this rather slight effect is of importance for tumour patients.

Antigens, CD↗

PubMed1999

[Value of mistletoe lectin standardized mistletoe extract for evaluating antitumor properties].

It could be shown from several experiments that carbohydrate-binding mistletoe lectins represent the pharmacologically active constituents of mistletoe extracts. On the basis of these findings, it was possible to develop an extract preparation standardized with respect to the mistletoe lectin concentration. This drug is the first mistletoe preparation that fulfills the criteria of the guidelines for the development of drugs (1) regarding its quality and stability of the active ingredients under certain storage conditions. The quality of this preparation has also been shown in several animal models to demonstrate antitumoral potencies.

Adjuvants, Immunologic↗

PubMed1990

Anti-mistletoe lectin antibodies are produced in patients during therapy with an aqueous mistletoe extract derived from Viscum album L. and neutralize lectin-induced cytotoxicity in vitro.

The humoral response components of an aqueous mistletoe extract (HM) was evaluated in 23 tumor patients who had been treated from 2 months up to 6 years with increasing dosages of HM. IgG antibodies against mistletoe lectin and other components of this extract were detected by ELISA, immunodiffusion, and blotting technique, using either the aqueous extract (HM) or a purified lectin preparation (ML). Their activity depended upon dosage of HM and length of therapy. No anti-HM/ML antibodies of the IgM type could be detected. Immunoblotting revealed lectin-specific antigens at 62 kD, 33k D, and 29 kD. In the presence of ML or HM, PHA-induced proliferation of normal lymphocytes was decreased in a dose-dependent manner; this effect was neutralized by adding the IgG fraction from pooled anti-HM-antibody-positive sera, indicating that the cytotoxic effect of lectins was eliminated by these specific antibodies. In view of these findings, it is questionable whether exposing tumor cells to mistletoe extracts in vivo exerts the same direct effect on tumor cells that is observed in vitro.

Blotting, Western↗

PubMed1998

Flow cytometric analyses of the specific activation of peripheral blood mononuclear cells from healthy donors after in vitro stimulation with a fermented mistletoe extract and mistletoe lectins.

Immunostimulatory properties of mistletoe extracts derived from Viscum album L. (VAL) are well described, demonstrating activation especially of T, T-helper cells and monocytes/macrophages. In order to characterise in detail the communication between different cell populations, we studied mistletoe-induced expression of co-stimulatory signals and their ligands by flow cytometry. Peripheral blood mononuclear cells (PBMC) from 15 healthy controls were incubated for 7 days with a fermented VAL extract. VAL significantly upregulated the expression of the co-stimulatory molecule B7.1 (CD80) on monocytes/macrophages, but not B7.2 (CD86). No significant changes in the expression of either molecules on B cells could be found, suggesting that only monocytes/macrophages act as antigen presenting cells (APCs) in this in vitro system. Purified mistletoe lectins, components of most VAL extracts were also analysed, but did not induce similar responses of monocytes/macrophages. The receptor for B7 molecules, CD28, but not CTLA-4 (CD152), was also found to be significantly enhanced on CD4+ cells after VAL simulation. There was no evidence for activation of a B cell response via the CD40/CD40L pathway. Our data support the concept that stimulation by VAL extracts induces a specific T-helper cell reaction with monocytes/macrophages acting as APCs and purified lectins do not exert the same effects.

Adult↗

PubMed2002

[Blood and tissue eosinophilia, mistletoe lectin antibodies and quality of life in a breast cancer patient undergoing intratumoral and subcutaneous mistletoe therapy].

BACKGROUND: Mistletoe therapy (MT) is a method of complementary medicine whose efficacy is controversially discussed. Until now there is a lack of data of high-dose intratumoral application. PATIENT AND METHODS: We are presenting a 3-year follow-up of an 80-year-old woman with metastasized breast cancer (c(2)T3/N1/M1) receiving combined intra- and peritumoral and subcutaneous MT with ABNOBAviscum(r) and concomitant pamitron acid. At time of admission the patient had bone metastases (thoracic vertebra 11 fracture), a lymphangiosis carcinomatosa, bilateral pleural effusions, and a reduced quality of life (QoL). RESULTS: Under MT we induced an eosinophilia and an elevation of eosinophil cationic protein (ECP). Simultaneously, we ascertained a reduction of 50% of Ca 15-3 and a sustained partial tumor remission. After 5 months the mistletoe-lectin-1 antibodies IgG-1 and -3 were maximally increased and we perceived a second Ca 15-3 reduction. After 3 months we observed a benefit in QoL. During the following 5 months the patient gained about 10 kg in weight. In the second year slow tumor progress was observed. After 19 months the patient had pneumonia which caused an MT pause. Subsequently, a combined intratumoral mistletoe and letrozol therapy brought a partial remission. The patient lived without chemo and radiation therapy more than 3 years with good QoL and died after 41 months, after a sepsis and a following stroke without signs of tumor progress. CONCLUSION: In metastasized breast cancer a palliative high-dose local MT can make a contribution to a tumor reduction and a benefit in QoL.

Aged↗

PubMedDate not supplied

Cytokine release of whole blood from adult female donors challenged with mistletoe lectin-1 standardised mistletoe extract and E. coli endotoxin or phytohaemagglutinin (PHA).

Cytokine (TNF, alpha, interleukin-6) release of whole blood from healthy donors was challenged with mistletoe extract standardised for mistletoe lectin-1 (sML) and control substances (E. coli endotoxin; phytohaemagglutinin). The rationale of this investigation was non-proven warnings that pro-inflammatory cytokines induce by the application of standardised mistletoe lectins may induce tumor cell proliferation. These investigations provided evidence that non-cytotoxic concentrations of sML did not induced enhanced TNFa or interleukin-6 secretion compared to non-challenged control cells. Cytotoxic concentrations of sML, however, induced significantly higher cytokine levels than the control, obviously due to non-physiological stimuli. Immunomodulation with clinically relevant, low-dose sML incubation did not induce proinflammatory cytokine secretion in vitro.

Adult↗

PubMed1996

Evaluation of the stimulatory activity of a fermented mistletoe lectin-1 free mistletoe extract on T-helper cells and monocytes in healthy individuals in vitro.

Previously, a strong stimulatory response of peripheral blood mononuclear cells (PBMC) to a fermented mistletoe extract (Iscador Pini, i.p.) could be observed in normal and allergic individuals. Aim of this study was therefore to analyse the cell subtypes involved in this in vitro reactivity. PBMC from 11 non-mistletoe treated healthy and allergic individuals were therefore investigated. Flow cytometric analyses revealed that this mistletoe extract stimulated T-cells (CD3+), especially T-helper cells (CD4+), as well as monocytes at concentrations of 100 or 1,000 micrograms/ml. Furthermore, an increased proportion of T- and T-helper cells expressing the interleukin-2 (IL-2) receptor (CD25) and monocytes expressing HLA-DR molecules, respectively, could be demonstrated. There was no evidence for a major involvement of B- (CD19+), natural killer- (NK-; CD56+) and T-suppressor cells/cytotoxic T-lymphocytes (CD8+). To get more insights whether the T-cell proliferation induced by i.p. was the consequence of a primary or a secondary type of immune response, kinetic studies (n = 5) were performed hereby comparing the reactivity of the non-recall antigen keyhole limpet hemocyanin (KLH) as well as the recall antigen purified protein derivative (PPD) derived from Mycobacterium tuberculosis with that of i.p. I.p. at a concentration of 100 micrograms/ml always exhibited the kinetics of a primary immune reaction. These findings were further substantiated by additional flow cytometric studies analysing changes in the proportions of naive (CD45RA+) and memory/effector cells (CD45RO+) during the exposure to i.p. It could be shown that the proportion of naive cells decreased and that of the transition stage increased, which could indicate that there was a change towards memory/effector cells. In conclusion, these data demonstrate that i.p.-related antigens act like "non-recall"-antigens, and the in vitro immune response involves T-cells as well as monocytes.

Adjuvants, Immunologic↗

PubMed2004

Isolation and quantification of chitin-binding mistletoe lectin from mistletoe extracts and validation of this method.

A method was established to isolate and quantify small amounts of chitin-binding mistletoe lectin (cbML) from extracts of the mistletoe (Viscum album L.) by affinity and reverse phase high performance liquid chromatography. A validation, according to ICH guidelines, of this analytical method was carried out and showed that specificity, robustness and precision are guaranteed. In addition, linearity is ensured for a content between 0.6 and 4.1 microg/ml of cbML in the extracts and recovery was calculated to be in the range of 94 to 100%. So, accuracy of the method is guaranteed as well. As far as the range of the analytical method is concerned, a minimum of 1.2 microg and a maximum of 8.2 microg cbML can be incubated with the affinity material. Detection and quantitation limits were calculated to be 0.13 and 0.46 microg/ml cbML, respectively.

Amino Acid Sequence↗