Activation of CD4-Positive T Cells by Polysaccharide Fractions Isolated from the Cupressaceae Thuja occidentalis L. (Arborvitae) *

Various mitogens have been described which act on different subpopulations of mouse and/or human peripheral lymphocytes. In recent years it has been mainly Japanese and German research teams that have isolated polysaccharide fractions with immunomodulative prop-erties [1-3, 17]. In addition to fungal polysaccharides such as lentinan, schizo-phyllan, and PSK polysaccharide, which are basically in the experimental step of clinical use [6, 10, 13], the focus of atten-tion has mainly been on plants belonging to the asteracean family, such as Echi-nacea purpurea and E. angustifolia, where an increase in granulocyte phagocytosis is observable. Thuja occidentalis L., a Cupressaceae, has hardly been investi-gated up till now. Several authors have demonstrated that allopathic extracts of this plant could be strong antiviral agents directed against plant and animal viruses [12, 3]. Polysaccharide fractions with molecular weights ranging between 5 x 105 and 1 x 106 and higher have been isolated from aqueous alkaline extracts of the herbal parts of Thuja occidentalis by ethanol precipitation and ultrafiltration using a Satorius Ultra Sart filtration cel