Effect of Spirulina on the secretion of cytokines from peripheral blood mononuclear cells

The purpose of this study was to evaluate the immunomodulatory activity of Spirulina, a blue-green alga used as a food supplement. The effects of Spirulina on the secretion of three cytokines from unstimulated and stimulated human peripheral blood mononuclear cells (PBMC) were examined. In resting PBMC, Spirulina stimulated secretion of interleukin (IL)-1β, IL-4, and interferon (IFN)-γ to nearly 2.0, 3.3, and 13.6 times basal levels, respectively. Spirulina induced levels of IFN-γ (229 ± 104 pg/ml) that were comparable to those seen after phytohemagglutinin (PHA) stimulation (476 ± 121 pg/ml). However, it was much less mitogenic than PHA (13.1 ± 6.9 pg/ml) with respect to the induction of IL-4 secretion (0.34 ± 0.1 pg/ml). In PHA-stimulated cells, Spirulina enhanced secretion of IL-1β, IL-4, and IFN-γ by 2.9, 4.0., and 1.6 times, respectively. Although Spirulina stimulates several cytokines, it is clearly more effective in the generation of a Th1-type response. This in vitro study offers additional data for consideration of the potential therapeutic benefits of Spirulina.