Immunoelectron microscopic study on interactions of noninfectious sendai virus and murine cells

Abstract

The early interactions of LLC-MK2 cell-grown noninfectious Sendai virus and a murine cell line, P815 mastocytoma ascitic cells, were studied by electron microscopy, using the ferritin-conjugated antibody technique with anti-virus glycoprotein serum. For comparison, the interactions of egg-grown infectious Sendai virus with the same cells were also examined. When noninfectious virus was adsorbed to the cells in the cold, the cell membranes become partially invaginated at the site of contact of adsorbed virions, but ferritin-conjugated antibodies did not penetrate into the areas of envelope-cell membrane association. This pattern of virus attachment was similar to that of infectious virus attachment. Upon subsequent incubation at 37°C, most of the adsorbed noninfectious virions were taken into cytoplasmic vesicles and then degraded, although a few virions remained attached to the cell membrane. No evidence of fusion of envelopes of noninfectious virions was obtained. On the other hand, envelopes of infectious virions fused with the cell membrane, and the transferred viral antigens diffused on the cell surfaces and then decreased in number.

Ultrastructural changes during lysis of L929 target cells by class II-restricted influenza virus-specific murine cytotoxic T-lymphocyte clones

“…Transfected or untransfected L929 target cells were cultured to a subconfluent state in a dish (Falcon 3001), pulsed with 50 hemagglutinating units of virus for 30 min, washed, and incubated at 37°C for 4 h. Effectors were then added at a cell ratio of 10:1. At intervals, cell sheets were gently washed with phosphate-buffered saline, fixed with Karnofsky fixative and osmium tetraoxide, dehydrated, and embedded as described previously (without immunoreactions) (29). Cell sheets were detached with propylene oxide treatment to maintain the morphological polarity of cells in a sheet.…”