Abstract
BackgroundThe binding of viral-specific antibodies to cell-surface antigens usually results in down modulation of the antigen through redistribution of antigens into patches that subsequently may be internalized by endocytosis or may form caps that can be expelled to the extracellular space. Here, by use of confocal-laser-scanning microscopy we investigated the kinetics of the modulation of respiratory syncytial virus (RSV) antigen by RSV-specific IgG. RSV-infected human epithelial cells (HEp-2) were incubated with anti-RSV polyclonal IgG and, at various incubation times, the RSV-cell-surface-antigen-antibody complexes (RSV Ag-Abs) and intracellular viral proteins were detected by indirect immunoflourescence.ResultsInteraction of anti-RSV polyclonal IgG with RSV HEp-2 infected cells induced relocalization and aggregation of viral glycoproteins in the plasma membrane formed patches that subsequently produced caps or were internalized through clathrin-mediated endocytosis participation. Moreover, the concentration of cell surface RSV Ag-Abs and intracellular viral proteins showed a time dependent cyclic variation and that anti-RSV IgG protected HEp-2 cells from viral-induced death.ConclusionThe results from this study indicate that interaction between RSV cell surface proteins and specific viral antibodies alter the expression of viral antigens expressed on the cells surface and intracellular viral proteins; furthermore, interfere with viral induced destruction of the cell.
Highlights
The binding of viral-specific antibodies to cell-surface antigens usually results in down modulation of the antigen through redistribution of antigens into patches that subsequently may be internalized by endocytosis or may form caps that can be expelled to the extracellular space
We present evidence that anti-respiratory syncytial virus (RSV) IgG induced redistribution of cell surface viral glycoproteins and that internalization of RSV Ag-Abs was partially inhibited by incubation in hypertonic medium, suggesting the participation of a clathrin-mediated mechanism
Anti-RSV IgG induced redistribution of viral glycoproteins on the surface of infected cells The interaction of RSV-specific IgG with cell surface RSV glycoproteins was determined by examining the binding of anti-RSV IgG to infected cells at 0, 10, 20, 30, 40, 50, or 60 minutes of incubation
Summary
The binding of viral-specific antibodies to cell-surface antigens usually results in down modulation of the antigen through redistribution of antigens into patches that subsequently may be internalized by endocytosis or may form caps that can be expelled to the extracellular space. Following exposure to specific antibodies, surface antigens are usually redistributed on the cell surface and are internalized or expelled into the extracellular medium [1,2]. These phenomena have been widely reported in virus systems [3,4,5], the best studied being an alpha herpes; in pseudorabies [6,7,8,9]. After the clathrin coated pits are introduced into the cell, the antibody-antigen complexes are degraded and the glycoproteins are directed back to the plasma membrane [8,9,10]
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