| 摘要 |
<p>Live Newcastle Disease virus vaccine is prepared by inoculating a non-avian tissue culture with a seed of an attenuated strain of Newcastle Disease virus, taken from avian tissue, cultivating the virus in the non-avian tissue culture and then harvesting the virus-containing fluid from the tissue culture before the appearance of a cytopathic effect in the tissue culture cells. The non-avian tissue culture used is preferably that obtained from the kidneys of monkeys, calves or pigs. The virus-containing fluid obtained may be mixed with a minor proportion by volume of bovine serum and/or skimmed milk and after adjusting, if necessary, the pH of the mixture so formed to approximately 7, protamine or clupeine sulphate is added and the resultant precipitate is harvested. This precipitate can be reconstituted to the desired concentration by admixture with a suitable diluent, e.g. physiologically-buffered saline solution.</p> |
