[Newcastle disease virus in tissue cultures studied by an immunofluorescence method]

Studied was the opportunity to demonstrate the Newcastle Disease Virus in tissue cultures with the employment of an immunofluorescence method. The development was followed up of four strains--the vaccinal ones Hitchner B1, La Sota, and Komarov and the velogenic one, Texas GB, using chick fibroblasts. It was found that the velogenic strain cumulated earlier and more intensely than the vaccinal ones, where the virus was seen to explicitly locate perivascularly. The most dependable demonstration of the virus proved possible with the velogenic strain at the 4th hour, and with the vaccinal strains--from the 6 th to the 10 th hour following the infection of the cultures. The virus antigen cumulated progressively, and with the velogenic strain it was accompanied with the production of a cytopathic effect which destroyed the cells by the 20th hour; with the vaccinal strains the cells remained intact up to the 48th hour following infection.