Role of apical and basolateral membranes in replication of human cytomegalovirus in polarized retinal pigment epithelial cells

Abstract

Human retinal pigment epithelial (RPE) cells, which are permissive for human cytomegalovirus (HCMV) replication, were used to evaluate virus infection from apical and basolateral membranes of polarized cells. Tests of HCMV infectivity showed that the apical membrane was 20-30-fold more susceptible to infection than the basolateral membrane; in contrast, both membranes were equally susceptible to infection by herpes simplex virus type 1 (HSV-1). Neutralizing monoclonal antibodies (MAbs) to HCMV glycoprotein B (gB) blocked penetration of virions into polarized RPE cells. This indicated that gB has a function in fusion of the virion envelope with the apical membrane of these cells, as it has with the cell membrane of unpolarized human fibroblasts. In contrast to HSV-l-infected RPE cells, the paracellular permeability of polarized RPE cells changed slowly following infection with HCMV. Confocal microscopy examination of HCMV-infected RPE cells revealed that the pattern of ZO-1 staining was altered at late times. Addition ofgB-specific neutralizing MAbs to the apical and basolateral membranes of HCMV-infected RPE cells failed to inhibit plaque development; this indicated that progeny virions infect adjacent cells before disassembly of tight junctions and are sequestered from neutralization during spread across lateral cell membranes. The finding that progeny HCMV virions cross lateral cell membranes, which differ substantially in protein composition from apical membranes, suggests that polarized RPE cells contain multiple receptors for HCMV.

Persistent Cytomegalovirus Infection in Amniotic Membranes of the Human Placenta

“…21 46e52, 71 Immediately evident was mislocalization of pp65, gB, and pp28, impaired transport of these proteins to MVBs, and failure to form a compact VAC that could reduce virus titers in infected AmEpCs. An innate immune response and prolonged IFN production that suppresses infection is usually transient because of expression of HCMV proteins that interfere with the response, which include pp65 delivery to the nucleus by incoming virions 72 and IE2 that functions as an IFN-b antagonist.…”

Virion Glycoprotein-Mediated Immune Evasion by Human Cytomegalovirus: a Sticky Virus Makes a Slick Getaway

“…Regardless of cell type or virus strain, antibody inhibition of cell-to-cell spread will depend on the ability of an antibody to access regions of CMV glycoproteins that are poised to engage with a bystander cell and initiate fusion. Virus spread in polarized ARPE-19 cells occurs across lateral membranes where glycoproteins are unaffected by neutralizing antibodies (186). Thus, consideration of in vivo mechanisms of viral spread as well as the requirements for antibody access and sufficient suppression of cell-to-cell spread should be considered in the design of vaccines and therapeutic antibodies ( Table 2).…”

Human Cytomegalovirus Transmission from the Uterus tothe Placenta Correlates with the Presence of Pathogenic Bacteria andMaternalImmunity

“…Since breast feeding (63), exposure to young children (46), and sexual contact (15) are major risk factors for infection, most adults are seropositive. Diverse organs and specialized cells, including polarized epithelial cells (67) and endothelial cells (13,34), are susceptible to CMV infection. Latent infection in granulocytemacrophage progenitors (26) reactivates upon cellular differentiation (18,60).…”