Behavior of lymphocyte subsets and expression of activation markers in response to immunotherapy with galactoside-specific lectin from mistletoe in breast cancer patients

Abstract

Cellular aspects of the immunomodulating activity of the galactoside-specific lectin from mistletoe (ML-1) were investigated in 10 cancer patients. Regular subcutaneous injections (4 weeks) of the optimal dosis of ML-1 (1 ng per kg body weight, twice a week) yielded notable increases in the apparent numbers of certain lymphocyte subsets [pan T cells; helper T cells; natural killer (NK) cells] which are generally believed to be involved in antitumor immunity. Moreover, ML-1 administration resulted in an increased level of expression of interleukin (IL)2 receptors on lymphatic cells, an indicator of cellular activation. In vitro, the exposure of human lymphocytes to ML-1 resulted in an enhanced expression of receptors for IL-2 (T cells) and HLA-DQ (B cells), which similarly substantiated the capacity of ML-1 to affect immunological parameters within the host defense system. Thorough clinical trials are now required to assess any impact of the application of the lectin on the course of the disease.

Recombinant mistletoe lectin induces p53-independent apoptosis in tumour cells and cooperates with ionising radiation

“…Mistletoe extracts are often used as complementary cancer treatment in addition to standard chemotherapy and radiation treatment and are reported to have an immunostimulatory and pain-relieving effect (Hajto et al, 1989;Beuth et al, 1992;Heiny et al, 1998;Stein and Berg, 1998;Ernst and Cassileth, 1999). A direct antitumour effect of mistletoe has been linked to the specific components lectin I -III that can induce apoptosis in various transformed cell lines, in particular in tumour cells of lymphoid origin.…”

Complete amino acid sequence of the A chain of mistletoe lectin I

“…ML-I is a component of a commercially available mistletoe extract with immunostimulating potency applied for the treatment of human cancer [7]. This immunomodulating capacity has recently been attributed to the presence of ML-I in the extract [8].…”

“…The general pathway(s) of activation of these mechanisms are still unknown, but specific mistletoe lectin-carbohydrate (cell glycoconjugate) interactions appear to be the effector system involved in eliciting such an immune response [14]. Controlled increases of these non-specific defence mechanisms may induce clinically beneficial immunomodulation in the treatment of cancer [7]. Accordingly, the detailed chemical structure of ML-I is crucial to elucidate its immunomodulatory capacity and for the design of more effective therapeutic substances.…”

Variable Sensitivity of Lymphoblastoid Cells to Apoptosis Induced by <i>Viscum album</i> Qu FrF, a Therapeutic Preparation of Mistletoe Lectin

“…Beuth et al [50] have demonstrated that ML-I enhanced expression of HLA-DQ on B cells. In vivo experiments have demonstrated that during treatment with MLs, anti-ML antibodies of IgG and IgE isotype are produced.…”