A study on the characteristics of La Sota strain of Newcastle disease virus adapted to grow in a cell line from bovine embryo kidney (BS/BEK).

The lentogenic La Sota strain of Newcastle disease virus (NDV) was adapted to grow in the BS/BEK cell line of bovine embryo kidney origin with a infectious titre similar to that in chicken embryos. No modification in the biological properties was detected after serial passages in the cell line, as indicated by CPE and by size and shape of the plaques. By contrast, the intracerebral pathogenicity index test, determined in 1-day-old chicks, was lower than for La Sota grown in chicken embryos. However, the immunogenicity of the cell culture adapted virus did not show any variation as demonstrated by serological response and by protection following challenge with virulent NDV. Accordingly, it appears that La Sota grown in cell cultures has retained its biological and immunological characteristics and if these results are confirmed by field trials and long term protection tests, the use of the BS/BEK cell line could be an alternative to chicken embryos for the cultivation of NDV.