Adaptation Newcastle Disease Virusvaccinal Strainin Vero Cell Line and Evaluation of Vaccine Safety Immunogenecity in Chicken under Laboratory Condition
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Date
2018-06
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Abstract
Newcastle disease (ND) is a highly infectious disease causing considerable economic losses to poultry industry worldwide. Traditionally, substrates for production of ND vaccines have been embryonated eggs, a method which has the disadvantages of being labor-intensive, time consuming and requires large area for the incubation of eggs. The present study was conducted to develop Vero cell-adapted, NDV I-2 vaccine and evaluate its safety and immunogenicity in chicken under laboratory condition. For this study, healthy and confluent monolayer of vero cell were further sub-cultured to prepare semi confluent monolayers then infected with 0.25 ml of Newcastle disease virus I-2 vaccine strain. The passage 1(P1) virus was harvested and used for the next passage in this way virus was given 12 serial passages on Vero cell line, where characteristic cytopathic effects (CPEs) were observed starting from fourth passages. Typical syncytium (irregularly shaped cells), gaint cells, clustering of infected cells, death of cells (plaque) were noticed on passage 4 from 72hourspost-infection. The positive hemagglutination and hemagglutination inhibition test confirmed that all vero cell adapted NDVI-2 adapted virus was Newcastle disease virus.The infectivity titer of adapted virus increased from log10 3.2 to log107.2 tissue culture infected dose/ ml.From the vaccine strain NDVI-2, Vero cell adapted live vaccine was produced. The antibody titer of experimental vero cell adapted live vaccine was determined in chicken by comparing with conventional live commercial vaccine (NDV I-2). Before experimental vaccination of the chicks, the level of antibody titre was very low (1.8±0.6). Following experimental vaccination, antibodies production were gradually increase after day 7 of post vaccination and the mean antibodies of the two vaccines (groups) were increased across each week of the followed up. The peak antibody titer was observed in the both groups at day 21 of post vaccination. After vaccination the two group chickens had antibody titres of >4 log2 starting from day and remain within protective range at day 35 final sera collection.The vaccine stain of NDV was well adapted to Vero cell line after successive passages and appeared equally immunogenic.
Description
A Thesis Submitted to the College of Veterinary Medicine and Agriculture of Addis
Ababa University in Partial fulfillment of the Requirements for the degree of
Master of Science in Veterinary Microbiology
Keywords
Adaptation, Antibody Titer, Cytophatic Effect