Ultrastructural and Immunofluorescence Studies of Early Events in Adenovirus-HeLa Cell Interactions

Abstract

SUMMARYScanning electron microscopy and immunofluorescence techniques show that the attachment of adenovirus type 5 to HeLa cells is followed by a temperature-dependent redistribution of virus particles on the cell surface. Metabolic inhibitors and cytochalasin B, a drug that impairs microfilament function, blocked this redistribution. Transmission electron microscopy studies demonstrated that inhibition of redistribution was paralleled by an inhibition of virus internalization. In further experiments virus and cells were incubated at 4 °C and then treated with adenovirus 'soluble' antigens to block unoccupied virus receptors. On warming these preparations to37 °C, the internalization of attached virions was found to be impaired. It is proposed that energy-dependent redistribution of attached adenovirus particles on the cell surface facilitates entry by bringing virions into contact with sufficient receptors to allow internalization.

Involvement of cellular adhesion sequences in the attachment of adenovirus to the HeLa cell surface

“…These two observations correlate with the fact that adhesion receptors are linked to the cytoskeleton, either directly, or indirectly, via actin filamentassociated talin (Burridge, 1987;Horwitz et al, 1986;Hynes, 1987;Ruoshlahti, 1988). They are also consistent with the results of a previous report showing that cytochalasin B, an inhibitor of microfilament functions, blocked Ad5 internalization (Patterson & Russell, 1983).…”

Radiation Enhances Adenoviral Gene Therapy in Pancreatic Cancer via Activation of Cytomegalovirus Promoter and Increased Adenovirus Uptake

“…Endocytosis of adenovirus mediated by clathrin-coated vesicles (44,45) requires the action of the large GTPase dynamin as a constrictase (46). It was recently reported that radiation induces adenovirus infection via dynamin 2 in colon cancer, brain cancer, and breast cancer (37,38).…”

Intravenous infusion of a replication-selective adenovirus (ONYX-015) in cancer patients: safety, feasibility and biological activity

“…45 Interaction with a second receptor, ␣ V -␤ 3,5 integrin, facilitates virus internalization into cells. 46 Internalization probably occurs by clathrin-mediated endocytosis, 47,48 an actin-dependent process, under the control of the PI3K pathway, 49 and may be therapeutically modulated by blocking of the Rho family of small GTP-binding proteins that serve as regulators of PI3K activation. 45,[50][51][52][53] Strategies to modulate the expression levels or function of these receptors in tumor tissues and/or normal organs are being developed and might eventually be tested in clinical trials.…”