| 摘要 |
<p>1,274,820. Newcastle disease virus. TAKEDA YAKUHIN KOGYO K.K. 27 Nov., 1970 [29 Nov., 1969], No. 56463/70. Heading A5B. A method of producing an attenuated Newcastle disease vaccine comprises: (1) cultivating Newcastle disease virus either by at least 20 serial passages in a porcine tissue culture or for at least 2 months in porcine stable cell lines to produce porcine cells containing attenuated virus, (2) inoculating this on to the chorioallantoic membrane of a chick embryo and cultivating the chick embryo and (3) recovering the virus from the resulting complex of chorioallantoic membrane and porcine cells and subjecting it to at least 2 serial passages in the allantoic cavity of a chick embryo. The procine tissue culture may contain primary kidney cells. Step (1) may be carried out by persistent infection of porcine stable cell lines with the virus. The virus recovered in step (3) may be further cultivated in a culture containing chick embryo cells to produce the vaccine.</p> |
