Fig. 4.

CD9 exosomal marker protein is carried with the virus inoculum to target cells. Lysates of mock-infected or infected cells (10 pfu/cell) were analyzed for the presence of ICP0, U_S11, and CD9 protein. In each case, β-actin served as a loading control. (lane 1) Mock-infected Vero cells; (lane 2) Vero cells infected with stock made in HEp-2 cells; (lane 3) Vero cells infected with virus stock serially passaged in HEp-2 cells; (lane 4) Vero cells infected with virus stock made in Vero cells (first Vero cell passage); (lanes 5 and 6) Vero cells infected with virus serially passaged two and three times in Vero cells; (lane 7) mock-infected HEp-2 cells; and (lane 8) HEp-2 cells infected with virus stock made in Vero cells. The CD9 protein was visualized with ECL detection reagent, whereas the ICP0, U_S11, and β-actin proteins were visualized with the BCIP-NBT reagents, as described in the main text.