Abstract
An in vitro model for testing natural substances is developed in this study. The model used mononuclear cells (MNCs) from human umbilical cord blood (hUCB) for phenotypic expression induction platform. Natural substances, such as Ganoderma or grape seed proanthocyanidins extract, were added to the medium and then cultured for seven days. The stem cells/progenitors contained in the mononuclear cells were modulated by the active ingredients and changed in the course of differentiation and maturation. Flow cytometry was used for phenotypic analysis. Meanwhile, we utilized a cell-fluid based microchip on Agilent Bioanalyzer, and discovered an alternative assay method for phenotypic expression studies. Such a measurement could analyze the phenotypes of cells in a small population as few as 200 cells with good sensitivity and accuracy. We found that Ganoderma lucidum extract could enhance the NK cells composition in immune cell subpopulation when used to treat hUCB MNCs. After treatment, the enriched NK cells preserved similar cytotoxicity function. Enrichment of specific subsets of immune cells enabled us to explore further studies, such as investigating the optimal effector-to-target cells ratio in this study, or potential future systems biology experiments during differentiation courses. The model was also utilized to screen different sort of natural substances. We found that, for example, wheat grass extract up-regulated CD 56+ NK cell composition, whereas rutin and quercetin down-regulated instead. Different fractions of natural substances could be further testified quickly with this platform. Furthermore, we observed no significant change as the concentration of natural substance was below a critical concentration. The optimal oral consumption dosage of a specific natural health product could be predicted. Taken together, we demonstrated that this technique provides a good platform to study natural substances. The responses of stem cells/progenitors to natural substances, the alteration in phenotypic expression of immune cell subpopulation, and the modulation of human immunity could be further explicated using this technique.