Mouse anti biotin antibody clone bk

EBV was detected by RNA in situ hybridization (ISH) with a 30-bp biotinylated probe (5’-AGACACCGTCCTCACCACCCGGGACTTGTA-3’) complementary to EBV-encoded small RNA-1 (Eber1), the most abundant viral product in latently infected cells [24 (link)]. Signal amplification was achieved with a mouse anti-biotin antibody (clone BK, 1:20 dilution; DakoCytomation®, CA, USA) and biotinylated rabbit anti-immunoglobulin antibody (polyclonal, 1:100 dilution; DakoCytomation®, CA, USA). The reaction was detected with streptavidin-biotin peroxidase complex (DakoCytomation®, CA, USA) and diaminobenzidine chromogen (DakoCytomation®, CA, USA). The slides were counterstained with Harris’s hematoxylin. Cell analysis was performed by 2 independent investigators using light microscopy, at 40x or 20x magnification. A total of 10 representative microscopic fields were evaluated, and fields containing less than 5 cells were not considered. A gastric cancer sample positive for EBV was included as a positive control, and two slides treated without probe were used as negative controls. Samples where 5% or more of the epithelial cells contained brown/red staining were considered positive. Although lymphocytes were also found to be infected by EBV, we did not include infected lymphoid cells in our analysis.