Establishment of a cell line for the production of vaccine against bovine leukaemia virus

Abstract

Bovine Leukaemia Virus (BLV) is a retrovirus that infect cattle, yak, water buffalo and zebu. The most common manifestation of the virus is an accumulation of infected B lymphocytes called persistent lymphocytosis (PL). This virus is present all over the world except in western Europe where a large campaign of testing and euthanasia of infected animals has been conducted. BLV economic impact is estimated at US$525 million due to a loss of milk production but also to a shorter animal lifespan. Preventive actions implemented to limit the spread of the virus often fail due to a lack of commitment to the programme. Therefore, a vaccine is urgently needed to facilitate herd management and disease control. A safe and effective vaccine based on an attenuated BLV strain (pBLV6073DX) has recently been developed. However, the current inoculation technique based on purified DNA does not allow for large-scale vaccination. In this context, the objective of this master thesis is to obtain a cell line expressing the vaccine strain in order to consider its larger-scale production. For this purpose, Vero cells were either transfected with the proviral insert or transduced with viral particles. After sorting with a flow cytometer and PCR-based clone selection, a cell line having stably integrated the vaccine sequence was isolated. Inoculation of sheep with this cell line effectively transmitted the vaccine strain, providing the proof-of-concept of the approach.