Plant-derived
flavonoids are inhibitors of various intracellular processes, notably phosphorylation pathways, and potential inhibitors of cellular autoimmunity. In this study, the inhibiting effects of various
flavonoids on
antigen-specific proliferation and
interferon-gamma (IFN-gamma) production by human and murine autoreactive T cells were evaluated in vitro. T-cell responses were evaluated for the human
autoantigen alpha B-crystallin, a candidate
autoantigen in
multiple sclerosis, and for the murine encephalitogen proteolipid
protein peptide PLP (139-151). The
flavones apigenin and
luteolin were found to be strong inhibitors of both murine and human T-cell responses while fisitin, quercitin,
morin and
hesperitin, members of the subclasses of flavonoles and
flavanones, were ineffective.
Antigen-specific IFN-gamma production was reduced more effectively by
flavones than T-cell proliferation, suggesting that the intracellular pathway for IFN-gamma production in T cells is particularly sensitive to
flavone inhibition. These results indicate that
flavones but not flavanoles or
flavanones are effective inhibitors of the potentially pathogenic function of autoreactive T cells. The effects of
flavones were the same for human and murine autoreactive T cells, stressing the usefulness of animal models of autoimmunity for further studies on the effects of flavonones on
autoimmune diseases.