Expression of surface molecules on NRS1 and 4-1BBL-transfected NRS1 cells. Parental NRS1 and 4-1BBL-transfected NRS1 (clone 5.13) cells were stained with either fluorescein isothiocyanate- or phycoerythrin-conjugated anti-4-1BBL, anti-CD80, anti-CD86, anti-CD54, anti-H-2Kk and anti-I-Ak, or an appropriate fluorochrome-conjugated immunoglobulin control. Samples were analysed by flow cytometry. Data are displayed as histograms (4-decade scale) with the immunoglobulin control as the lighter line.