Immunoprotective activity of the galactoside-specific mistletoe lectin in cortisone-treated BALB/c-mice.

Hydrocortisone-acetate (HA)-treatment of BALB/c-mice induced a profound suppression of the lymphatic immune system with statistically significant decreases of thymocyte proliferation and maturation rates as well as peripheral blood lymphocyte (PBL) counts. To check its putative immunoprotective/immunorestoring activity, the optimal immunomodulating dosage of commercially available mistletoe extract standardized for the galactoside-specific mistletoe lectin (ML-1) was regularly administered (1 ng ML-1 per kg body weight; subcutaneously). As compared to counts of thymic lymphatic subsets of HA-treated mice, a considerable up regulation of mature cells expressing helper/inducer (L3T4+) as well as cytotoxic/suppressor (Lyt-2+) phenotypes and immature cells expressing both antigens (L3T4+/Lyt-2+) could be found after ML-1 co-administration. Counts of BALB/c-mouse peripheral blood mononuclear cells also revealed statistically significant increases after ML-1 co-administration, as compared to HA-treated animals. Accordingly, ML-1 treatment may be supposed to restore the lymphatic system after immunosuppressive corticoid treatment and thus this treatment may be of great benefit to patients.