Investigations of cellular parameters to establish the response of a biomodulator: Galactoside-specific Lectin from Viscum album plant extract

Injections of non-toxic doses of purified galactoside-specific lectin from the Viscum album plant (VAA-I) caused significant changes in the cellular host defense system in animal models. To establish the immunomodulatory potency of VAA-I on human subjects, four randomized double blind crossover trials were performed on healthy volunteers. In the first and second trials using either older (storage over 8 months at 4 degrees C) or freshly (application immediately after production) isolated lectin enriched preparation from mistletoe extract by ultrafiltration with known VAA-I content, the effect of lectin on the number of CD3+, CD4+, CD8+, CD 16+/56+ cells, natural killer cytotoxicity and frequency of large granular lymphocytes was tested in peripheral blood of nine and eight individuals, respectively. In comparison to the significant increase in the number of peripheral lymphocytes observed in balb/c mice, human healthy individuals showed no significant difference between their responses after lectin enriched preparation and saline treatment. Due the considerable intrinsic fluctuation of these parameters in placebo control and the assumption that a change in immunomodulatory potency of VAA-I in lectin enriched preparation depends on aging, a third and fourth double blind trial, in this case using freshly isolated VAA-I from plant, were performed on six and eight healthy volunteers, respectively. In these studies an other more rapidly detectable parameter, the priming of polymorphonuclear (PMN) leukocytes, was monitored. Tn both studies, 5 h after lectin injection, significant enhancement in priming of circulating PMNs was found compared to the placebo response.