Identification and localization of glycoprotein B expression in lymphoid tissues of chickens infected with turkey herpesvirus.

One-day-old chickens were inoculated with turkey herpesvirus (HVT). Using an indirect immunofluorescence assay with a monoclonal antibody against HVT glycoprotein B (gB), we determined the course of productive HVT infection in peripheral blood mononuclear cells (PBMCs), spleen, thymus, and bursa. PBMCs were examined from days 4 through 35 postinfection (PI). The spleen, thymus, and bursa were examined from 21 through 70 days PI. Although productive infection in PBMCs was detected at 4 to 12 days PI, it ended by 14 days PI. Splenic cells expressed gB at 21, 28, 35, and 70 days PI, whereas the thymus was positive for gB expression at 21 and 35 days PI. The bursa was never positive for gB expression. At 21, 28, 35, and 70 days PI, plaque formation after co-cultivation of PBMCs with chicken embryo fibroblasts indicated the presence of HVT in infected chickens by co-cultivation assays. On the basis of indirect immunofluorescence assay, gB expression in the spleen and thymus indicates a productive HVT infection in chickens.