Virus-induced fusion of human erythrocyte ghosts. I. Effects of macromolecules on the final stages of the fusion reaction.
Human erythrocyte ghosts prepared by hypotonic hemolysis can be fused by Sendai virus, provided that certain macromolecules (bovine serum albumin, dextran and others) are sequestered in the ghosts. Since fusion of the ghosts is dependent on intactness of the F(fusion)-glycoprotein of the virion, and since the other requirements for this reaction are also similar to those for the Sendai virus-induced fusion of intact erythrocytes, this system can be used as a model for the Sendai virus-induced cell fusion reaction. Sequestered macromolecules seem to be required for rounding of locally fused ghosts. Under low osmotic swelling conditions, such as use of ghosts sealed without macromolecules or using bovine serum albumin-loaded ghosts sealed in the presence of external macromolecules, no apparently complete cell fusion (large spherical polyghost formation) could be observed. Even under these conditions, however, occurrence of local cell fusion could be demonstrated either by transfer of fluorescent-labeled albumin from one ghost to an other, or by observation of polyghost formation after osmotic swelling in the cold. Thus, final stages of the fusion reaction can be divided into local cell-cell fusion which could not be observed by phase-contrast microscopy, and rounding (i.e. formation of spherical polyghosts). For the observation of fusion of ghosts, the last step seems to be important.
D000418:Albumins / Q000494:pharmacology; D002459:Cell Fusion / Q000187:drug effects; D004910:Erythrocyte Membrane / Q000187:drug effects*; D004912:Erythrocytes / Q000187:drug effects*; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008954:Models, Biological; D010222:Parainfluenza Virus 1, Human
D000418:Albumins; D006023:Glycoproteins; D046911:Macromolecular Substances