Protein aggregation complicates the development of baculovirus-expressed African horsesickness virus serotype 5 VP2 subunit vaccines.
This paper describes the expression of a cloned African horsesickness virus (AHSV) serotype 5 VP2-gene by a baculovirus recombinant that was generated by the BAC-TO-BAC system. Immunization of horses with crude cell lysates containing recombinant baculovirus-expressed AHSV5 VP2 did induce neutralizing antibodies, but afforded only partial protection against virulent virus challenge. Further analysis of partially protective crude cell lysates revealed that baculovirus-expressed AHSV5 VP2 was predominantly present in the form of insoluble aggregates. Only approximately 10% of VP2 was present in a soluble form. Immunization of guinea-pigs with aggregated and soluble forms of AHSV5 VP2 established that only soluble VP2 was capable of inducing neutralizing antibodies. This finding adds a new dimension to the development of AHSV VP2s as subunit vaccines. Further investigation is needed to limit formation of insoluble aggregates and optimize conditions for producing VP2 in a form capable of inducing protective immunity.
du Plessis
M
M
Biochemistry Division, Onderstepoort Veterinary Institute, South Africa.
Cloete
M
M
Aitchison
H
H
Van Dijk
A A
AA
D000356:African Horse Sickness Virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood; D016367:Baculoviridae / Q000235:genetics*; D003001:Cloning, Molecular / Q000379:methods; D005822:Genetic Vectors / Q000145:classification; D006168:Guinea Pigs; D006734:Horse Diseases / Q000276:immunology / Q000517:prevention & control; D006736:Horses; D011994:Recombinant Proteins / Q000032:analysis; D014611:Vaccination / Q000379:methods / Q000662:veterinary; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
D000914:Antibodies, Viral; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic