VZV Foundation - A Decade Of Leadership In The Fight Against VZV Infections

	Oral Presentation Abstracts: 63 [63] CHARACTERIZATION OF THE VIRAL HIGHWAYS OF VARICELLA ZOSTER VIRUS INFECTED CELLS *Jorge Padilla and Charles Grose Departments of Microbiology and Pediatrics, University of Iowa, Iowa City, IA. Varicella Zoster virus (VZV) infection induces the formation of membrane fusion with subsequent syncytia formation that includes hundreds of nuclei. The virus egresses onto the cell surface in an unusual pattern which has been called viral highways. These viral highways occur only on the surface of the syncytia. The goal of this project was to further characterize the protein structure of the viral particles within the viral highways. In order to compare the relative amounts of glycoproteins gE, gI, gB and gH expressed on these viral highways, glycoproteins were labeled indirectly by using monoclonal antibodies against the specific glycoproteins followed by a secondary antibody couple with ultra small gold particles (0.2 nm) and silver enhanced for better visualization; the patterns of staining were analyzed by using an ultra-high resolution scanning electron microscope (LEO530) at magnifications that range from 50,000X up to 400,000X. To determine the label density of each of the glycoproteins of interest, an average of 100 viral particles in at least 5 different experiments were examined per glycoprotein, and the mean gold-labeling density was assessed. VZV gE as well as VZV gI molecules were found in an unusual linear distribution on the surface of the cells in the late stages of infection. It was observed that VZV gE and gI were present mainly within the envelopes of emergent viral particles on the cell surface at an average of 20 gold beads per virion. In contrast, VZV gB molecules were found on viral particle surface at an average of 10 to 15. In the case of VZV gH molecules, labeling was detected only on the leading edge surface and not on the virions. The latter experiments were repeated with two different anti-gH antibodies. These results do not agree with calculations for the prototypical HSV-1 particle, which on basis of protein concentration calculations, was estimated to contain over 300 molecules of gB and 5200 of gH per envelope. Thus, these VZV studies suggested that the particle in the viral highway was enclosed by an aberrant envelope structure. Corresponding Author: J. Padilla Ph.D., University of Iowa, Steindler Bldg 1612, Iowa City, USA 52242, USA

[63]

CHARACTERIZATION OF THE VIRAL HIGHWAYS OF VARICELLA ZOSTER VIRUS INFECTED CELLS

*Jorge Padilla and Charles Grose
Departments of Microbiology and Pediatrics, University of Iowa, Iowa City, IA.

Varicella Zoster virus (VZV) infection induces the formation of membrane fusion with subsequent syncytia formation that includes hundreds of nuclei. The virus egresses onto the cell surface in an unusual pattern which has been called viral highways. These viral highways occur only on the surface of the syncytia. The goal of this project was to further characterize the protein structure of the viral particles within the viral highways.

In order to compare the relative amounts of glycoproteins gE, gI, gB and gH expressed on these viral highways, glycoproteins were labeled indirectly by using monoclonal antibodies against the specific glycoproteins followed by a secondary antibody couple with ultra small gold particles (0.2 nm) and silver enhanced for better visualization; the patterns of staining were analyzed by using an ultra-high resolution scanning electron microscope (LEO530) at magnifications that range from 50,000X up to 400,000X. To determine the label density of each of the glycoproteins of interest, an average of 100 viral particles in at least 5 different experiments were examined per glycoprotein, and the mean gold-labeling density was assessed.

VZV gE as well as VZV gI molecules were found in an unusual linear distribution on the surface of the cells in the late stages of infection. It was observed that VZV gE and gI were present mainly within the envelopes of emergent viral particles on the cell surface at an average of 20 gold beads per virion. In contrast, VZV gB molecules were found on viral particle surface at an average of 10 to 15. In the case of VZV gH molecules, labeling was detected only on the leading edge surface and not on the virions. The latter experiments were repeated with two different anti-gH antibodies. These results do not agree with calculations for the prototypical HSV-1 particle, which on basis of protein concentration calculations, was estimated to contain over 300 molecules of gB and 5200 of gH per envelope. Thus, these VZV studies suggested that the particle in the viral highway was enclosed by an aberrant envelope structure.

Corresponding Author: J. Padilla Ph.D., University of Iowa, Steindler Bldg 1612, Iowa City, USA 52242, USA