Chimaeric virus-like particles derived from consensus genome sequences of human rotavirus strains co-circulating in Africa
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Date
2014Author
Jere, Khuzwayo C.
Van Dijk, Alberdina A.
O'Neill, Hester G.
Potgieter, A. Christiaan
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Rotavirus virus-like particles (RV-VLPs) are potential alternative non-live vaccine candidates due to their high
immunogenicity. They mimic the natural conformation of native viral proteins but cannot replicate because they do not
contain genomic material which makes them safe. To date, most RV-VLPs have been derived from cell culture adapted
strains or common G1 and G3 rotaviruses that have been circulating in communities for some time. In this study, chimaeric
RV-VLPs were generated from the consensus sequences of African rotaviruses (G2, G8, G9 or G12 strains associated with
either P[4], P[6] or P[8] genotypes) characterised directly from human stool samples without prior adaptation of the wild
type strains to cell culture. Codon-optimised sequences for insect cell expression of genome segments 2 (VP2), 4 (VP4), 6
(VP6) and 9 (VP7) were cloned into a modified pFASTBAC vector, which allowed simultaneous expression of up to four
genes using the Bac-to-Bac Baculovirus Expression System (BEVS; Invitrogen). Several combinations of the genome
segments originating from different field strains were cloned to produce double-layered RV-VLPs (dRV-VLP; VP2/6), triplelayered
RV-VLPs (tRV-VLP; VP2/6/7 or VP2/6/7/4) and chimaeric tRV-VLPs. The RV-VLPs were produced by infecting
Spodoptera frugiperda 9 and Trichoplusia ni cells with recombinant baculoviruses using multi-cistronic, dual co-infection and
stepwise-infection expression strategies. The size and morphology of the RV-VLPs, as determined by transmission electron
microscopy, revealed successful production of RV-VLPs. The novel approach of producing tRV-VLPs, by using the consensus
insect cell codon-optimised nucleotide sequence derived from dsRNA extracted directly from clinical specimens, should
speed-up vaccine research and development by by-passing the need to adapt rotaviruses to cell culture. Other problems
associated with cell culture adaptation, such as possible changes in epitopes, can also be circumvented. Thus, it is now
possible to generate tRV-VLPs for evaluation as non-live vaccine candidates for any human or animal field rotavirus strain
URI
http://hdl.handle.net/10394/18918https://doi.org/10.1371/journal.pone.0105167
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0105167