Cytokine relative expression in bovine, caprine and ovine stimulated PBMC samples. Abbreviations. PBMC, peripheral blood mononuclear cells. Abbreviations for reference genes, see Table 1. PBMCs were cultured with medium (unstimulated condition) or stimulated with 5 μg/ml of Concanavalin A (stimulated condition) for 36 h. The relative expression ratio (Er) of cytokine genes in Concanavalin A-stimulated cells compared to unstimulated cells was calculated (amplification of three independent experiments in duplicate) in bovine (A), caprine (B) and ovine (C) samples using the relative expression software tool (REST) with the most stable combination of two reference genes identified with NormFinder software. REST Software uses randomization technique and error bars represents distribution of permutated expression data. Black boxes represent up-regulated cytokine expression and white boxes down-regulated cytokine expression.