id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-004766-gvom0f13	Traavik, T.	Improvement of arbovirus HA antigens by treatment with a colloidal silica gel and sonication	1977		.txt	text/plain	2232	167	62	A remarkable increase in HA titers for weakly haemagglutinating Norwegian arbovirus strains, Uukuniemi and Runde viruses, was achieved by including treatment with the colloidal silica gel Aerosil in the antigen preparation scheme. Good antigens also were obtained from virus grown in BHK 21/c 13 cell cultures and concentrated by polyethylene glycol 6000/NaCl. Rubella virus HA antigen and HB(s)Ag were adsorbed to the gel, and excluded from a preparation by treatment with Aerosil. For production of arbovirus haemagglutinating (HA) antigens, the classical sucrose-aeeton extraction method (SA) (3) with infected suckling mouse brains has been almost undisputed, although methods based on infected cell culture fluids (2, 12) and infected mouse aseites fluids (8) have also been reported. Infected brain suspensions and PEG treated cell culture concentrates were titrated by intraeerebral inoculation in suckling mice after Aerosil absorption, incubation with shaking in waterbath at 45 ° C and untreated. Simple method for preparation of haemagglutinating arbo-A virus antigens from brains of suckling mice	./cache/cord-004766-gvom0f13.txt	./txt/cord-004766-gvom0f13.txt