Expression of the Multimeric and Highly Immunogenic Brucella spp. Lumazine Synthase Fused to Bovine Rotavirus VP8d as a Scaffold for Antigen Production in Tobacco Chloroplasts

ALFANO EF, LENTZ EM, BELLIDO D, DUS SANTOS MJ, GOLDBAUM FA, WIGDOROVITZ A, BRAVO-ALMONACID FF

Frontiers in Plant Science

Frontiers Editorial Office

Lugar: Lausanne; Año: 2015 vol. 6

Lumazine synthasefrom Brucella spp. (BLS) is a highly immunogenic decameric protein which can accommodateforeign polypeptides or protein domains fused to its N-termini, markedly increasingtheir immunogenicity. The inner core domain (VP8d) of VP8 spike protein from bovinerotavirus is responsible for viral adhesion to sialic acid residues and infection.It also displays neutralizing epitopes, making it a good candidate for vaccination.In this work, the BLS scaffold was assessed for the first time in plants for recombinantvaccine development by N-terminally fusing BLS to VP8d and expressing the resultingfusion (BLSVP8d) in tobacco chloroplasts. Transplastomic plants were obtained andcharacterized by Southern, northern and western blot. BLSVP8d was highly expressed,representing 40% of total soluble protein (4.85 mg/g fresh tissue). BLSVP8d remainedsoluble and stable during all stages of plant development and even in lyophilizedleaves stored at room temperature. Soluble protein extracts from fresh and lyophilizedleaves were able to induce specific neutralizing IgY antibodies in a laying henmodel. This work presents BLS as an interesting platform for highly immunogenicinjectable, or even oral, subunit vaccines. Lyophilization of transplastomic leavesexpressing stable antigenic fusions to BLS would further reduce costs and simplifydownstream processing, purification and storage, allowing for more practical vaccines.