One of the major applications of biotechnology in the health industry is the development of a range of safe and effective new generation human and animal vaccines. In many cases the new vaccination strategies are based on the use of recombinant proteins or peptides to induce a protective immune response. This requires a strategy that will present peptides in their optimum configuration to the immune system. The development of vaccine presentation or delivery systems is therefore the basis of most recombinant vaccine strategies. Even though a large number of such systems have been developed, many still reflect serious shortcomings. These limitations are often with respect to the size, the solubility and the number of peptides that can be displayed at the same time.
One of the projects at the University of Pretoria, funded by the BioPAD Biotechnology Regional Innovation Centre, and coordinated by Prof Henk Huismans in the Department of Genetics, is focused on the development of a platform technology that aims to address some of these problems. Two unique peptide presentation systems are under investigation that can be used to present a variety of peptides and small proteins of different sizes to the immune system. These presentation strategies will then be used to develop recombinant vaccines against economically important diseases such as African horsesickness (AHS) and foot-and-mouth disease (FMD). The current live or inactivated vaccines still play a very important role in protection against these diseases but they do not always meet with the current safety requirements. The key products of this vaccine delivery platform are range of genetically engineered vectors, composed of either of two AHS virus proteins. The unique features of these proteins are that they spontaneously assemble into either crystalline or tubular particles that have been shown to have strong immunogenic properties and that can be produced in large amounts.
The genes for these AHS virus proteins have been modified so that different peptides can be presented as projections on the surface of these particles. These chimeric particles will be tested for their ability to induce neutralizing or protective antibodies in small animals. If promising results are obtained, it will initiate the future development of a variety of recombinant animal vaccines against diseases such as AHS, bluetongue, FMD, bovine ephemeral fever and Rift Valley fever. The use of the vaccination strategy is not confined to animal diseases and may have value in the development of vaccines against HIV or other human pathogens.