The immunomodulating properties of
arglabin, a
sesquiterpene lactone isolated from Artemisia myriantha Wall. (Asteraceae) were investigated using the murine macrophage
tumor line J774.1.
Arglabin-stimulated macrophages displayed a strong cytotoxic activity and the lowest doses (1.25 micrograms/mL and 0.125 micrograms/mL) induced a significant stimulation of cell mitochondrial metabolism, which correlated with [3H]TdR uptake by J774.1 cells under the same experimental conditions. In addition, the secretion of
cytokines involved in host defence mechanisms--IL-1,
TNF-alpha, and IL-2--was investigated upon incubation of J774-1 cells with
arglabin.
Arglabin triggered the production of the three
cytokines from J774-1 cells. However, the pattern of
cytokine secretion differed to some extent, according to the methodology used for
cytokine measurement: either traditional bioassay or specific immunoassay (ELISA). Our data emphasize a possible proliferative effect of
arglabin in the traditional bioassays, at least for the highest concentrations used. The results were verified with specific ELISA immunoassays. Using either method, lower concentrations of
arglabin (ranging from 12.5 micrograms/mL to 0.125 micrograms/mL) were the most effective in inducing
IL-1,
TNF-alpha, or
IL-2 secretion. In addition, preliminary data on phagocytosis showed that
arglabin enhanced the uptake of fluorescent
latex beads by J774.1 cells.