VERO CELL ADAPTATION, IMMUNOGENICITY AND EFFICACY TEST OF INFECTIOUS BURSAL DISEASE VIRUS (LC-75) VACCINE STRAIN FOR VERO CELL BASED VACCINE DEVELOPMENT IN ETHIOPIA
No Thumbnail Available
Date
2018-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Infectious bursal disease (IBD) is an acute and contagious viral disease of young chicks caused by Infectious bursal disease virus (IBDV). The disease is seriously affecting the poultry production. Vaccination is the major controlling method of the disease. Vaccine production using chicken fibroblast primary cell is time consuming, laborious, and uneconomical. The present study was carried out to adapt the LC-75 designated vaccine strain of infectious bursal disease virus using Vero cell culture, to evaluate immunogenicity and efficacy of the adapted virus to develop Vero cell based vaccine. Accordingly, Vero-cells at passage 20 with confluent monolayer was infected with 0.5 ml of LC-75 vaccine strain virus by adsorption method and recorded as passage 1. This process has been done up to 10 successive passages by following the same methods of virus infection onto Vero cells. The virus showed good cytopathic effects starting from passage 3. The infectivity titre of adapted virus was conducted and the result showed a linear increment of the titre along the passage number. The positive results of reverse transcriptase polymerase chain reaction targeting the VP2 gene revealed amplification of the 645 base pair. The VP2 gene nucleotide sequence analysis derived from Vero cell adapted virus and chicken fibroblast cell based prepared vaccine showed the absence of any nucleotide variation. A 0.03ml of Vero cell adapted virus from passage 5 and passage 10 was inoculate into 14 day chicks through eye drop to evaluate the level of antibody produced. Detection of the antibody level was conducted by indirect enzyme linked immune sorbent assay technique. The statistical result revealed that the absence of any significant antibody titre difference between the three groups of experimental chicks. Efficacy test was conducted by challenging non-vaccinated chicks (control group), one group vaccinated with passage 5 and third group vaccinated with passage 10 using Vero cell adapted very virulent infectious bursal disease virus circulating in the country. The Vero cell adapted virus at passage 5 and passage 10 protected the chicken 100%; whereas 60% morbidity and 25% mortality was observed in the control group. Therefore, IBDV LC-75 vaccine strain is well adapted on Vero cell, and immunogenic and efficacious to protect against the circulating virus isolates. Thus, IBD vaccine production using Vero cells is recommended.
Description
A thesis submitted to the College of Veterinary Medicine and Agriculture of Addis Ababa University in partial fulfillment of the requirements of the degree of Masters of Science in Veterinary Microbiology
Keywords
IBD vaccine virus, chicken, ELISA, immunogenic