Rat IgG anti-LMP1 (clones 8G3 and 1G6, Ascenion) were used at 1:10 dilution from tissue culture supernatants, followed with 8 μg/ml biotinylated mouse F(ab') anti-rat IgG (H+L) pre-adsorbed to mouse serum (Jackson ImmunoResearch) and 2 μg/ml streptavidin-alkaline phosphatase conjugate (Jackson ImmunoResearch).