Specificity of UL6, UL17, and UL25 monoclonal antibodies. Cells were infected with HSV-1 wt virus strain 17, wt virus strain KOS, UL17-stop virus, lacZ-UL6−, or KUL25NS or were mock infected (MI). At 20 h postinfection the cells were harvested and the proteins were separated by SDS-PAGE and blotted onto a nitrocellulose membrane. The blot was probed sequentially with monoclonal antibodies UL6 Mab175, UL17 Mab203, and UL25 Mab166 as well as VP23-specific rabbit antibodies.