DCs infected with herpes simplex virus type 1 adhere to fibronectin and down-regulate CYTIP expression. (A) Quantification of adherent cells shows that, as early as 4 hours after infection, HSV-1 strongly increases the fibronectin adherence of infected DCs. Mature DCs were mock-infected (white columns) or infected with UV-inactivated virus (gray columns) or HSV-1 (black columns) at a MOI of 1. At the indicated time points after infection, cells were allowed to adhere to fibronectin-coated 96-well plates. Adherence was quantified by measuring β-glucuronidase activity of adherent cells. (B) Fibronectin adhesion of HSV-1-infected DCs (MOI 1) is mediated by integrins and is specific for fibronectin. Four hours after infection, DCs were treated with 1mM Mn²⁺ or 5mM EDTA and were allowed to adhere to fibronectin-coated (black columns) or gelatin-coated (gray columns) 96-wells. Adherence was quantified by measuring β-glucuronidase activity. Mn²⁺ has no significant effect on the adhesion of infected DCs, whereas ethylenediaminetetraacetic acid completely blocks adhesion. Neither mock-infected nor HSV-1-infected DCs adhere to gelatin. Error bars represent ± SD. ***P < .001. ns indicates not significant. Experiments were repeated at least 3 times independently. Each single experiment was performed in quadruplicate.