Establishment of a reverse genetics system for rotavirus vaccine
strain LLR and developing vaccine candidates carrying VP7 gene cloned
from human strains circulating in China
Abstract
Human rotavirus A (RVA) causes acute gastroenteritis in infants and
young children. The LLR RVA vaccine, which licensed in 2000 and widely
used in China, significantly reduced rotavirus disease burden in China.
With the exchanges of RV circulating strains and the emergence of new
genotypes, the LLR vaccine against RVGE needed to be upgraded. In this
study, we aimed to establish an RG system for the RVA vaccine strain LLR
(G10P[15]). Transfection with plasmids expressing 11 genomic RNA
segments of LLR along with the pCMV/868CP helper plasmid, resulted in
rescue of the infectious virus with an artificially introduced genetic
marker on its genome, indicating that an RG system for the LLR strain
was successfully established. Furthermore, the plasmid‐based reverse
genetics system was used to generate lamb RVA reassortants with VP4 and
VP7 genes derived from human RVA strains in China, which were not
previously adapted to cell culture. We were able to rescue the six VP7
(G1, G2, G3, G4, G8, and G9) mono‐reassortants, but no VP4 (P[4] or
P[8]) mono‐reassortant was rescued. The six VP7 reassortants covered
all G-genotypes currently circulating in China and stably replicated in
MA104 cells, which should be exploited as the next generation rotavirus
vaccines candidates in China. Furthermore, the LLR RG system in this
study will be a useful vaccine vector for intestinal pathogens such as
norovirus and Vibrio cholerae.