Attenuation of lentogenic Newcastle disease virus strain B-1 by cold adaptation

• Published in: Avian diseases Vol. 40; no. 3; p. 605
• Main Authors: Gelb, J. Jr. (University of Delaware, Newark, DE.), King, D.J, Wisner, W.A, Ruggeri, P.A
• Format: Journal Article
• Language: English
• Published: United States 01.07.1996
• Subjects: ADAPTACION; ADAPTATION; Animals; Antibodies, Monoclonal; ANTIGENE; ANTIGENOS; Chick Embryo - virology; Chickens - immunology; Chickens - virology; Cold Temperature; CONTROL DE ENFERMEDADES; CONTROLE DE MALADIES; ENFERMEDADES RESPIRATORIAS; FRIO; FROID; IMMUNOGENETIQUE; INDICE DE CRECIMIENTO; INMUNOGENETICA; LESION; LESIONES; MALADIE RESPIRATOIRE; Newcastle Disease - immunology; Newcastle Disease - prevention & control; Newcastle Disease - virology; Newcastle disease virus - immunology; Newcastle disease virus - pathogenicity; PATOGENICIDAD; POLLITO; POLLO; POULET; POUSSIN; POUVOIR PATHOGENE; TAUX DE CROISSANCE; VACCIN; Vaccines, Attenuated - immunology; VACUNA; Viral Vaccines - immunology; VIRUS DE LA ENFERMEDAD DE NEWCASTLE; VIRUS MALADIE DE NEWCASTLE
• ISSN: 0005-2086; 1938-4351
• DOI: 10.2307/1592271

The Hitchner B-1 strain of Newcastle disease virus was plaque-cloned and then serially passaged 36 times in specific-pathogen-free (SPF) chicken embryos incubated at two different temperatures. Virus passaged at a reduced temperature (29 C) was identified as cold-adapted (Ca) and virus passaged at the normal temperature (37 C) was designated non-cold-adapted (non-Ca). The Ca and non-Ca B-1 viruses were compared with the parent B-1 and a commercial B-1 vaccine. In vitro Ca B-1 characteristics included adaptation for more rapid growth at 29 C and the aquisition of temperature sensitivity indicated by substantially reduced growth at 41 C, properties not seen with non-Ca B-1. Embryo mean death times for the Ca virus (140 hr) were longer than for non-Ca B-1 (107 hr) and parent B-1 (121 hr) viruses. The Ca virus retained a rapid (2 hr) hemagglutination (HA) elusion rate but lost the property of binding the monoclonal antibody AVS-I typical of other B-1 strains. The pathogenicity of the Ca B-1 strain was compared to the non-Ca B-1, parent B-1 strain, and a commercial B-1 strain vaccine in 1-day-old broiler-type chickens. Pathogenicity was evaluated by assessing the severity of respiratory disease signs and the incidence of airsacculitis, perihepatitis, and pericarditis lesions in inoculated chicks. A respiratory disease index was calculated for each B-1 strain based on daily observation scores that determined the presence or absence of disease signs (coughing, rales, labored breathing, death) from 1 to 14 days following intratracheal inoculation with 10(6), 50% egg infective doses of virus per chick. The lower respiratory disease index obtained for the Ca B-1 strain (0.075) indicated it was less pathogenic than the commercial B-1 vaccine (0.296) and the non-Ca (0.478) and parent (0.521) B-1 strains. Ca B-1-infected chicks had only a 5% incidence of air sac lesions, compared to chicks given non-Ca (65%), Hitchner B-1 (65%), or a commercial B-1 vaccine (30%)