ANTIBODY-INDUCED AND CYTOSKELETON-MEDIATED REDISTRIBUTION AND SHEDDING OF VIRAL GLYCOPROTEINS, EXPRESSED ON PSEUDORABIES VIRUS-INFECTED CELLS

Fluorescein isothiocyanate-labeled porcine pseudorabies virus (PrV) po lyclonal antibodies were added to PrV-infected swine kidney cells in v itro at 37 degrees C. In approximately 47% of the infected cells, the addition induced passive patching and subsequent energy- and microtubu le-dependent capping of all viral envelope glycoproteins, expressed on the plasma membranes of the infected cells, Further contraction and e xtrusion of the capped viral glycoproteins occurred in approximately 3 0% of the capped cells 2 h after the addition of antibodies and was ac companied by a concentration of F-actin beneath the caps. At that time , about 18% of the extruded caps were shed spontaneously into the surr ounding medium, Mechanical force released 85% of the extruded caps, le aving viable cells with no microscopically detectable levels of viral glycoproteins on their plasma membranes, Experiments with PrV deletion mutants showed that viral glycoproteins gE and gI are important in tr iggering viral glycoprotein redistribution. Since the PrV gE-gI comple x exhibits Fc receptor activity which facilitates capping, the importa nce of gE and gI may be partially explained by antibody bipolar bridgi ng.