id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-290695-ubrqy2zf	Payne, H. R.	Analysis of cell fusion induced by bovine coronavirus infection	1988		.txt	text/plain	2078	109	50	Polykaryon formation in bovine fetal spleen (BFS) cells infected with bovine coronavirus L9 occurred only in media supplemented with trypsin. Cell fusion and polykaryon formation in cultures infected with bovine coronavirus (BCV) occur late in the virus replication cycle. We analyzed the trypsin-dependent cell fusion of BCV-infected BFS cells and found that the range of pH 7.5 to 8.0 was optimal for polykaryon formation. The cells were inoculated with BCV at a multiplicity of 2 PFU per cell, incubated in MEM containing trypsin (0.4 ug per ml; Sigma Chemical Company) treated with L-l-tosylamide-2-phenylethyl chloromethyl ketone, an inhibitor of chymotrypsin activity. The ability of anti-BCV IgG to affect polykaryon formation at 37 °C was tested by two procedures: (i) Infected cell monolayers were incubated for 6 h in trypsin-free MEM then exposed to MEM that contained antibody freshly diluted with trypsin containing medium. Trypsin treatments of BCV-infected BFS cells during the time of maximal fusion enhancement were effective only with media of pH levels 7.5 to 8.0.	./cache/cord-290695-ubrqy2zf.txt	./txt/cord-290695-ubrqy2zf.txt