Condensed tannins from Botswanan forage plants are effective priming agents of γδ T cells in ruminants.

Abstract

The potential impact of extracts from forage plants on y8 T cell activity in ruminants was evaluated using an in vitro immunoassay. This study investigated whether plant extracts could prime y8 T cells via up-regulation of CD25 (interleukin-2 receptor alpha). Purified Sephadex LH-20 fractions, isolated from Viscum rotundifolium, Viscum verrucosum, Tap- inanthus oleifolius and Grewia flava, were screened against y8 T cells on kid, lamb and calf peripheral blood lymphocytes. Condensed tannins (CT) from G. flava significantly primed y8 T cells in kids up to 64.75% at 10 ug/mL, which was statistically significant relative to the negative control at 22.66% (p = 0.004). CT from T. oleifolius also induced priming of y8 T cellsin kids, while fractions from V. rotundifolium and V. verrucosum induced minimal priming of y8 T cells. In contrast, there was no significant priming of y8 T cells from lambs and calves for any of the tested fractions (p > 0.05). These findings suggest that CT from a selected range of Botswanan forage plants can stimulate the immune system in vivo in selected ruminant species and may participate in enhancing host innate immune responses.