CD80 expression on porcine peripheral blood mononuclear cell (PBMC) and podocytes. (a) Pig PBMCs were stimulated with lipopolysaccharide (LPS) (5 μg/ml) for 24 h. CTLA4-Ig (at 0.25–5 μg/ml) was added and incubated for 3 h before LPS stimulation. CD80 expression was evaluated with flow cytometry (a-1). The mean MFI value in each of the groups was shown in the bar graph (a-2). Pig PBMC expressed CD80 (red line in the histogram, and third bar from left in the bar graph). CTLA4 Ig markedly inhibited CD80 expression. (b) Although resting pig podocytes did not express CD80 (blue line in the histogram and the second bar in the bar graph), LPS (5 μg/ml) stimulation induced CD80 upregulation (b-1, 2, red in histogram, and third bar from left in the bar graph). Pretreatment of CTLA4-Ig completely suppressed CD80 expression (green line in the histogram, and the fourth bar in the bar graph).