Das Lektin der Mistel als Immunmodulator: Biochemische Charakterisierung, Effektorwirkung auf intrazelluläre Biosignalketten und Zytokinfreisetzung sowie Richtlinien für onkologische Anwendung

Abstract: The biochemical, cell biological and immunological investigation of extracts with reported clinical efficiency offers the possibility to define up to now uncharacterized potent pharmaceuticals. In the case of the mistletoe extract the optimized biochemical purification of the ß-galactoside-specific lectin and the establishment of a sensitive detection system for standardization of extracts with respect to the lectin content are prerequisites to unequivocally prove that this extract component causes clinically relevant immunomodulation via protein (lectin)-carbohydrate (cellular glycoconjugate)-recognition. Application of the optimal dosis of 1 ng lectin/kg body weight accounts for enhancement of several factors that characterize the host defence system. The use of this dosis of purified lectin in animal studies or of lectin in extracts in clinical trials leads to a comparable extent of augmentation, whereas lectin-depleted extract fails to be immunomodulatory. On the cellular level secretion of cytokines is stimulated, quantitative alterations in protein phosphorylation, phospholipid metabolism and Ca 2+ mobilization possibly being involved in this reaction in response to lectin binding to macrophages that is ascertained glycocytologically. Increased cytokine secretion in vitro translates into enhanced serum levels in patients. In combination with chemo- or radiotherapy biweekly lectin injections are a supportive treatment modality. The documented controlled lectin-dependent immunomodulation warrants comprehensive clinical studies to assess its putative value.

Keyword(s): Lektin

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