Page 20 - VHSA - Onderstepoort 100 Years - Part 3

OND
ERSTEPOORT 100
of Utrecht in the Netherlands, which enabled him to start a very ambitious project aimed at determining the complete nucleotide sequence of the E. ruminantium genome. By 2002
excellent progress had been made with the genome pro- ject, but the work was in- creasingly being hampered by the continual loss of key senior research personnel. In 2003 Basil Allsopp decided to accept a long-standing offer
of a position at the Veteri-
nary Faculty of the University
of Pretoria to strengthen their biotechnology programme, but
he maintained close collaboration with the OVI group, now led by M. (Mirinda) van Kleef.
In 2004 the genome project was successfully completed and the fully anno- tated sequence was published in the Proceedings of the National Academy of Sciences of the USA in January 2005. This was the first bacterial genome to be sequenced in South Africa, or indeed anywhere in Africa. The genetic information thus made available allowed a more ratio- nal selection of genes with potential for vaccine production. Several genes have been identified which code for proteins which
110 stimulate T-lymphocytes and interferon production and which are thus potentially good recombinant vaccine candidates. Vaccine trials of these genes are ongoing, but it is a long and expensive process.
With the reorganization of 1992/93, research in the Section of Biochemistry was consolidated into two programmes: ‘New Viral Vaccines and Diagnostics’ under the leadership of van Dijk, and ‘Pox-vectored Vaccines’ with Viljoen as manager. The first programme encompassed further development of PCR tests for orbiviruses, improved cloning procedures for double- stranded RNA and immunochemical studies including epitope mapping. The surface protein VP2 of AHSV was cloned, sequenced and expressed in baculovirus recombinants and proved to be immunogenic. Viljoen’s programme consisted mainly of studying the potential of lumpy skin disease virus (LSDV) and other poxviruses as carriers for recombinant sub-unit vaccines. This
work was done in close collaboration with experts at University of Cape Town, in- cluding Williamson, who continued for a number of years with contract research for the ARC-OVI. Transfer vectors for LSDV were developed and recombinants with Rift Valley fever virus (RVFV) and bovine ephemeral fever virus (BEFV) constructed. Attempts were also made to construct LSDV/BTV recombinants with less success. A reverse tran- scriptase-based PCR test (RT- PCR) for the non-structural NS2 protein of AHSV proved to be 100X more sensitive than previous group-specific tests for the virus. By 1995 PCR tests became important that it was decided to establish a dedicated PCR laboratory under the guidance of Viljoen, both to raise the standard of diagnostic work and to develop
and commercialize new tests.
Biotechnology and
Immunochemistry
By 1996 this programme had been so successful that it developed into an in- dependent section called Applied Biotech- nology. Within a year the laboratory had established seven routine PCR diagnostic tests with six more under development. A brucellosis kit with commercial potential had been developed as well as a new recombinant fowl pox/Newcastle disease vaccine. The remaining four years of the 20th century were spent in testing and further developing the vaccines and the diagnostic tests, contributing substantially to the diagnostic programme. Important contributions were made by D.B. (Dave) Wallace, M. (Marko) Romito, B. (Batty) Dungu-Kimbenga, L. Mare, C.W. (Christine) Vroon (neé Bremer), C.E. (Charlotte) Ellis and F.T. (Frank) Vreede.
In 1996 immunochemical research be- came an independent programme called ‘Immunological Approaches to Disease Control’ with Dion du Plessis as manager and head of a new Immunology Section. Du Plessis pioneered the introduction of phage display technology in South Africa which was used initially to identify genes of AHSV
Schematic representation of the circular Ehrlichia ruminantium genome
so
“By 1996 this programme had been so successful that it developed into an independent section called Applied Biotechnology. Within a year the laboratory had established seven routine PCR diagnostic tests with six more under development.”
PART 3
History of Individual Disciplines
1908-2008
Years